Planet Lisp

Quicklisp newsOctober 2021 Quicklisp dist update now available

· 34 hours ago

 New projects

  • alexandria-plus — A conservative set of extensions to Alexandria utilities — Microsoft Public License
  • autoexport — A small library to automatically export definitions — BSD-3-Clause
  • — Wrapper for the Cephes Mathematical Library — Microsoft Public License
  • cl-apertium-stream-parser — Apertium stream parser written in Common Lisp — Apache-2.0
  • cl-bus — A(n almost) referentially transparent interface for streams — BSD-3
  • cl-cram — A simple, Progress bar for Common Lisp — MIT
  • cl-earley-parser — Natural language parser using Jay Earleys well-known algorithm — MIT
  • cl-etcd — Run etcd as an asynchronous inferior process. — AGPL3
  • cl-gcrypt — Common Lisp bindings for libgcrypt — LGPLv2.1
  • cl-termbox — Bindings for termbox library, a minimalistic library for building text-mode applications without curses — MIT license
  • cl-with — WITH- group with- macros, allocate objects and rebind slots — BSD 3-clause
  • cl-yxorp — A reverse proxy server that supports WebSocket, HTTP, HTTPS, HTTP to HTTPS redirecting, port and host forwarding configuration using a real programming language, HTTP header and body manipulation (also using a real programming language). — AGPL3
  • claxy — Simple proxy middleware for clack — Apache License, version 2.0
  • clerk — A cron-like scheduler with sane DSL — MIT
  • clingon — Command-line options parser system for Common Lisp — BSD 2-Clause
  • clutter — Cluttering classes and slots with annotations/decorators/attributes metadata — LGPL
  • commondoc-markdown — Converter from Markdown to CommonDoc. — Unlicense
  • compiler-macro-notes — Provides a macro and some conditions for use within macros and compiler-macros. — MIT
  • ctype — An implementation of the Common Lisp type system. — BSD
  • docs-builder — A meta documentation builder for Common Lisp projects. — Unlicense
  • funds — portable, purely functional data structures in Common Lisp — Apache 2.0
  • geodesic — Library for geodesic calculations. — ISC
  • hashtrie — An implementation of the Hash Trie datastructure, based on Clojure's — Eclipse 2.0
  • mcase — Control frow macros with case comprehensiveness checking. — Public domain
  • mnas-path — Describe mnas-path here — GNU GENERAL PUBLIC LICENSE Version 3, 29 June 2007 or later
  • parsnip — Parser combinator library — BSD 3-Clause
  • promise — A small, independent promise library for asynchronous frameworks — zlib
  • quick-patch — Easily override quicklisp projects without using git submodules — Mozilla Public License 2.0
  • strict-function — Utility of function definition — MIT
  • vivid-colors — colored object printer — MIT
  • vivid-diff — Colored object diff viewer. — MIT

Updated projects: 3d-matrices, also-alsa, april, architecture.builder-protocol, bdef, beast, bike, bnf, bp, chameleon, check-bnf, chirp, ci-utils, cl+ssl, cl-ana, cl-ansi-term, cl-ansi-text, cl-async, cl-bloggy, cl-collider, cl-colors2, cl-cron, cl-data-structures, cl-dbi, cl-digraph, cl-environments, cl-form-types, cl-forms, cl-gearman, cl-gserver, cl-info, cl-kraken, cl-liballegro-nuklear, cl-libsvm, cl-marshal, cl-megolm, cl-mixed, cl-opencl, cl-opencl-utils, cl-patterns, cl-pdf, cl-permutation, cl-png, cl-readline, cl-schedule, cl-sdl2-mixer, cl-ses4, cl-telebot, cl-utils, cl-wave-file-writer, cl-webdriver-client, cl-webkit, cletris, clj-re, clog, closer-mop, cluffer, clunit2, clx, cmd, colored, common-lisp-jupyter, concrete-syntax-tree, consfigurator, core-reader, croatoan, cytoscape-clj, dartsclhashtree, data-frame, defmain, dfio, djula, dns-client, doc, doplus, easy-routes, eclector, esrap, fare-scripts, fof, fresnel, functional-trees, gadgets, gendl, generic-cl, glacier, gtirb-capstone, gute, harmony, hash-table-ext, helambdap, hunchenissr, imago, ironclad, jingoh, kekule-clj, lack, lambda-fiddle, lass, legit, lisp-namespace, lisp-stat, literate-lisp, log4cl, log4cl-extras, lsx, maiden, markup, math, matrix-case, mcclim, messagebox, mgl-pax, micmac, millet, mito, mnas-graph, mnas-hash-table, mnas-package, mnas-string, mutility, null-package, numerical-utilities, nyxt, omglib, osicat, parachute, petalisp, physical-quantities, plot, portal, postmodern, pp-toml, prompt-for, qlot, query-repl, quilc, read-as-string, resignal-bind, rove, rpcq, salza2, sel, serapeum, sha1, shasht, shop3, sketch, slite, smart-buffer, spinneret, staple, static-dispatch, stealth-mixin, structure-ext, swank-protocol, sycamore, tfeb-lisp-hax, tfeb-lisp-tools, tooter, trace-db, trestrul, trivia, trivial-with-current-source-form, uax-15, uncursed, vellum, vellum-postmodern, vgplot, vk, whirlog, with-c-syntax, zippy.

Removed projects: adw-charting, cl-batis, cl-bunny, cl-dbi-connection-pool, cl-reddit, cl-server-manager, corona, gordon, hemlock, hunchenissr-routes, prepl, s-protobuf, submarine, torta, trivial-swank, weblocks-examples, weblocks-prototype-js, weblocks-tree-widget, weblocks-utils.

To get this update, use (ql:update-dist "quicklisp").

There are a lot of removed projects this month. These projects no longer build with recent SBCLs, and all bug reports have gone ignored for many months. If one of these projects is important to you, consider contributing to its maintenance and help it work again.

Incidentally, this is the eleventh anniversary of the first Quicklisp dist release back in October 2010.

TurtleWareSelective waste collection

· 36 hours ago

When an object in Common Lisp is not reachable it is garbage collected. Some implementations provide the functionality to set finalizers for these objects. A finalizer is a function that is run when the object is not reachable.

Whether the finalizer is run before the object is deallocated or after is a nuance differing between implementations.

On ABCL, CMU CL, LispWorks, Mezzano, SBCL and Scieener CL the finalizer does not accept any arguments and it can't capture the finalized object (because otherwise it will be always reachable); effectively it may be already deallocated. As the least common denominator it is the approach taken in the portability library trivial-garbage.

(let* ((file (open "my-file"))
       (object (make-instance 'pseudo-stream :file file)))
  (flet ((finalize () (close file)))
    (trivial-garbage:set-finalizer object (lambda () (close file))))

On contrary ACL, CCL, clasp, clisp, corman and ECL the finalizer accepts one argument - the finalized object. This relieves the programmer from the concern of what should be captured but puts the burden on the programmer to ensure that there are no circular dependencies between finalized objects.

(let ((object (make-instance 'pseudo-stream :file (open "my-file"))))
  (flet ((finalize (stream) (close (slot-value stream 'file))))
    (another-garbage:set-finalizer object #'finalize)))

The first approach may for instance store weak pointers to objects with registered finalizers and when a weak pointer is broken then the finalizer is called.

The second approach requires more synchronization with GC and for some strategies makes it possible to absolve objects from being collected - i.e by stipulating that finalizers are executed in a topological order one per the garbage collection cycle.

In this post I want to discuss a certain problem related to finalizers I've encountered in an existing codebase. Consider the following code:

(defclass pseudo-stream ()
  ((resource :initarg :resource :accessor resource)))

(defun open-pseudo-stream (uri)
  (make-instance 'pseudo-stream :resource (make-resource uri)))

(defun close-pseudo-stream (object)
  (destroy-resource (resource object))))

(defvar *pseudo-streams* (make-hash-table))

(defun reload-pseudo-streams ()
  (loop for uri in *uris*
        do (setf (gethash uri *pseudo-streams*)
                 (open-pseudo-stream uri))))

The function reopen-pseudo-streams may be executed i.e to invalidate caches. Its main problem is that it leaks resources by not closing the pseudo stream before opening a new one. If the resource consumes a file descriptor then we'll eventually run out of them.

A naive solution is to close a stream after assigning a new one:

(defun reload-pseudo-streams/incorrect ()
  (loop for uri in *uris*
        for old = (gethash uri *pseudo-streams*)
        do (setf (gethash uri *pseudo-streams*)
                 (open-pseudo-stream uri))
           (close-pseudo-stream old)))

This solution is not good enough because it is prone to race conditions. In the example below we witness that the old stream (that is closed) may still be referenced after a new one is put in the hash table.

(defun nom-the-stream (uri)
    (let ((stream (gethash uri *pseudo-streams*)))
      (some-long-computation-1 stream)
      ;; reload-pseudo-streams/incorrect called, the stream is closed
      (some-long-computation-2 stream) ;; <-- aaaa

This is a moment when you should consider abandoning the function reload-pseudo-streams/incorrect and using a finalizer. The new version of the function open-pseudo-stream destroys the resource only when the stream is no longer reachable, so the function nom-the-stream can safely nom.

When the finalizer accepts the object as an argument then it is enough to register the function close-pseudo-stream. Otherwise, since we can't close over the stream, we close over the resource and open-code destroying it.

(defun open-pseudo-stream (uri)
  (let* ((resource (make-resource uri))
         (stream (make-instance 'pseudo-stream :resource resource)))

    #+trivial-garbage ;; closes over the resource (not the stream)
    (flet ((finalizer () (destroy-resource resource)))
      (set-finalizer stream #'finalizer))

    #+another-garbage ;; doesn't close over anything
    (set-finalizer stream #'close-pseudo-stream)


Story closed, the problem is fixed. It is late friday afternoon, so we eagerly push the commit to the production system and leave home with a warm feeling of fulfilled duty. Two hours later all hell breaks loose and the system fails. The problem is the following function:

(defun run-client (stream)
  (assert (pseudo-stream-open-p stream))
  (loop for message = (read-message stream)
        do (process-message message)
        until (eql message :server-closed-connection)
        finally (close-pseudo-stream stream)))

The resource is released twice! The first time when the function run-client closes the stream and the second time when the stream is finalized. A fix for this issue depends on the finalization strategy:

#+trivial-garbage ;; just remove the reference
(defun close-pseudo-stream (stream)
  (setf (resource stream) nil))

#+another-garbage ;; remove the reference and destroy the resource
(defun close-pseudo-stream (stream)
  (when-let ((resource (resource steram)))
    (setf (resource stream) nil)
    (destroy-resource resource)))

With this closing the stream doesn't interfere with the finalization. Hurray! Hopefully nobody noticed, it was late friday afternoon after all. This little incident tought us to never push the code before testing it.

We build the application from scratch, test it a little and... it doesn't work. After some investigation we find the culpirt - the function creates a new stream with the same resource and closes it.

(defun invoke-like-a-good-citizen-with-pseudo-stream (original-stream fn)
  (let* ((resource (resource original-stream))
         (new-stream (make-instance 'pseudo-stream :resource resource)))
    (unwind-protect (funcall fn new-stream)
      (close-pseudo-stream new-stream))))

Thanks to our previous provisions closing the stream doesn't collide with finalization however the resource is destroyed for each finalized stream because it is shared between distinct instances.

When the finalizer accepts the collected object as an argument then the solution is easy because all we need is to finalize the resource instead of the pseudo stream (and honestly we should do it from the start!):

(defun open-pseudo-stream (uri)
  (let* ((resource (make-resource uri))
         (stream (make-instance 'pseudo-stream :resource resource)))
    (set-finalizer resource #'destroy-resource)

(defun close-pseudo-stream (stream)
  (setf (resource stream) nil))

When the finalizer doesnt't accept the object we need to do the trick and finalize a shared pointer instead of a verbatim resource. This has a downside that we need to always unwrap it when used.

(defun open-pseudo-stream (uri)
  (let* ((resource (make-resource uri))
         (wrapped (list resource))
         (stream (make-instance 'pseudo-stream :resource wrapped)))
    (flet ((finalize () (destroy-resource resource)))
      (set-finalizer wrapped #'finalize)

(defun close-pseudo-stream (stream)
  (setf (resource stream) nil))

When writing this post I've got too enthusiastic and dramatized a little about the production systems but it is a fact, that I've proposed a fix similar to the first finalization attempt in this post and when it got merged it broke the production system. That didn't last long though because the older build was deployed almost immedietely. Cheers!

Eitaro FukamachiDay 1: Roswell, as a Common Lisp implementation manager

· 3 days ago

This is my first public article in English. I've been sending out newsletters about what I've been doing only to sponsors, but there have been requests to publish my know-how on my blog, so I'm writing this way.

However, my English skills are still developing, so I can't suddenly deliver a lot of information at once. So instead, I'm going to start writing fragments of knowledge in the form of technical notes, little by little. The articles may not be in order. But I suppose each one would help somehow as a tip for your Common Lisp development.

When I thought of what I should start from, "Roswell" seemed appropriate, because most of the topics I want to tell depends on it.

It's been six years since Roswell was born. Although its usage has been expanding, I still feel that Roswell is underestimated, especially among the English community.

Not because of you. I think a lot of the reason for this is that the author is Japanese, like me, and has neglected to send out information in English.

If you are not familiar with Roswell or have tried it before but didn't get as much use out of it as you wanted, I hope this article will make you interested.

What's Roswell

Roswell has the following features:

  • Install Common Lisp implementations of specific versions and switch between them as needed
  • Install libraries from GitHub
  • Common Lisp scripting (aka. Roswell script)
  • Enthusiastic CI support

It would be too much work to explain everything in a single article, so I will explain from the first one today: installation of Common Lisp implementations.

Installation of Common Lisp implementations

To install implementations with Roswell, use its "install" subcommand.

$ ros help install

To install a new Lisp implementaion:
   ros install impl [options]
or a system from the GitHub:
   ros install fukamachi/prove/v2.0.0 [repository... ]
or an asdf system from quicklisp:
   ros install quicklisp-system [system... ]
or a local script:
   ros install ./some/path/to/script.ros [path... ]
or a local system:
   ros install ./some/path/to/system.asd [path... ]

For more details on impl specific options, type:
   ros help install impl

Candidates impls for installation are:

For instance, SBCL, currently the most popular implementation, can be installed with sbcl-bin or sbcl.

# Install the latest SBCL binary
$ ros install sbcl-bin

# Install the SBCL 2.1.7 binary
$ ros install sbcl-bin/2.1.7

# Build and install the latest SBCL from the source
$ ros install sbcl

Since Roswell author builds and hosts its own SBCL binaries, it can install more versions of binaries than the official binary support. So in most cases, you can just run ros install sbcl-bin/<version> to install a specific version of SBCL.

After installing a new Lisp, it will automatically be in the active one. To switch implementations/versions, ros use command is available.

# Switch to SBCL 2.1.7 binary version
$ ros use sbcl-bin/2.1.7

# Switch to ECL of the latest installed version
$ ros use ecl

To see what implementations/versions are installed, ros list installed is available.

$ ros list installed
Installed implementations:

Installed versions of ecl:

Installed versions of sbcl-bin:

Installed versions of sbcl-head:

To check the active implementation, run ros run -- --version.

# Print the active implementation and its version
$ ros run -- --version
SBCL 2.1.7

Run REPL with Roswell

To start a REPL, execute ros run.

# Start the REPL of the active Lisp
$ ros run

# Start the REPL of a specific implementation/version
$ ros -L sbcl-bin/2.1.7 run

"sbcl" command needed?

For those of you who have been installing SBCL from a package manager, the lack of the sbcl command may be disconcerting. Some people are relying on the "sbcl" command in your editor settings. As a workaround to install the "sbcl" command, such as the following command would help.

$ printf '#!/bin/sh\nexec ros -L sbcl-bin run -- "$@"\n' | \
    sudo tee /usr/local/bin/sbcl \
  && sudo chmod +x /usr/local/bin/sbcl

Though once you get used to it, I'm sure you'll naturally start using ros run.


I introduced the following subcommand/options in this article.

  • Subcommand
    • install <impl>
      • Install a new Lisp implementation
    • use <impl>
      • Switch another installed Lisp implementation
    • run
      • Start a REPL
  • Options
    • -L
      • Specify the Lisp implementation to run a command

(Rough) Troubleshooting

If you have a problem like "Roswell worked fine at first but won't work after I updated SBCL," simply delete ~/.roswell .

Roswell writes all related files under the directory, like configurations, Lisp implementations, and Quicklisp libraries, etc. When the directory doesn't exist, Roswell creates and initializes it implicitly. So it's okay to delete ~/.roswell.

TurtleWareA curious case of HANDLER-CASE

· 3 days ago

Common Lisp is known among Common Lisp programmers for its excellent condition system. There are two operators for handling conditions: handler-case and handler-bind:

(handler-case (do-something)
  (error (condition)
    (format *debug-io* "The error ~s has happened!" condition)))

(handler-bind ((error
                 (lambda (condition)
                   (format *debug-io* "The error ~s has happened!" condition))))

Their syntax is different as well as semantics. The most important semantic difference is that handler-bind doesn't unwind the dynamic state (i.e the stack) and doesn't return on its own. On the other hand handler-case first unwinds the dynamic state, then executes the handler and finally returns.

What does it mean? When do-something signals an error, then:

  • handler-case prints "The error ... has happened!" and returns nil
  • handler-bind prints "The error ... has happened!" and does nothing

By "doing nothing" I mean that it does not handle the condition and the control flow invokes the next visible handler (i.e invokes a debugger). To prevent that it is enough to return from a block:

(block escape
  (handler-bind ((error
                   (lambda (condition)
                     (format *debug-io* "The error ~s has happened!" condition)
                     (return-from escape))))

With this it looks at a glance that both handler-case and handler-bind behave in a similar manner. That brings us to the essential part of this post: handler-case is not suitable for printing the backtrace! Try the following:

(defun do-something ()
  (error "Hello world!"))

(defun try-handler-case ()
  (handler-case (do-something)
    (error (condition)
      (trivial-backtrace:print-backtrace condition))))

(defun try-handler-bind ()
  (handler-bind ((error
                   (lambda (condition)
                     (trivial-backtrace:print-backtrace condition)
                     (return-from try-handler-bind))))

When we invoke try-handler-case then the top of the backtrace is

2: ((FLET "FUN1" :IN TRY-HANDLER-CASE) #<SIMPLE-ERROR "Hello world!" {1002D77DD3}>)

While when we invoke try-handler-bind then the backtrace contains the function do-something:

2: ((FLET "H0" :IN TRY-HANDLER-BIND) #<SIMPLE-ERROR "Hello world!" {1002D9CE23}>)
3: (SB-KERNEL::%SIGNAL #<SIMPLE-ERROR "Hello world!" {1002D9CE23}>)
4: (ERROR "Hello world!")

Printing the backtrace of where the error was signaled is certainly more useful than printing the backtrace of where it was handled.

This post doesn't exhibit all practical differences between both operators. I hope that it will be useful for some of you. Cheers!

Max-Gerd RetzlaffuLisp on M5Stack (ESP32):<br /> controlling relays connected to I2C via a PCF8574

· 3 days ago

relay module connected to I2C via a PCF8574; click for a larger version (180 kB).

Looking at the data sheet of the PCF8574 I found that it will be trivially simple to use it to control a relay board without any lower level Arduino library: Just write a second byte in addtion to the address to the I2C bus directly with uLisp's WITH-I2C.

Each bit of the byte describes the state of one of the eight outputs, or rather its inverted state as the PCF8574 has open-drain outputs and thus setting an output to LOW opens a connection to ground (with up to 25 mA), while HIGH disables the relay. (The data sheets actually say they are push-pull outputs but as high-level output the maximum current is just 1 mA which is not much and for this purpuse certainly not enough.)

The whole job can basically done with one or two lines. Here is switching on the forth relay (that is number 3 with zero-based counting):

(with-i2c (str #x20)
  (write-byte (logand #xff (lognot (ash 1 3))) str))

Here is my whole initial library:

Read the whole article.

TurtleWareHow do you DO when you do DO?

· 7 days ago

In this short post I'll explain my understanding of the following quote describing the iteration construct do:

The Common Lisp do macro can be thought of as syntactic sugar for tail recursion, where the initial values for variables are the argument values on the first function call, and the step values are argument values for subsequent function calls.

-- Peter Norvig and Kent Pitman, Tutorial on Good Lisp Programming Style

Writing a recursive function usually involves three important parts:

  1. The initial values - arguments the programmer passes to the function
  2. The base case - a case when function may return without recurring
  3. The step values - arguments the function passes to itself when recurring

An example of a recursive function is this (inefficient) definition:

(defun fib (n)
    ((= n 0) 0)
    ((= n 1) 1)
    (t (+ (fib (- n 1))
          (fib (- n 2))))))

The initial value here is n, base cases are (= n 0) and (= n 1) and the step values are (- n 1) and (n 2).

To make a function tail-recursive there is one more important requirement: the subsequent function call must be in a tail position, that is it must be the last function called. The definition above is not tail-recursive, because we first need to call the function and then add results. A proper tail-recursive version requires little gimnastic:

(defun fib* (n)
  (labels ((fib-inner (n-2 n-1 step)
             (if (= step n)
                 (+ n-2 n-1)
                 (fib-inner n-1
                            (+ n-2 n-1)
                            (1+ step)))))
      ((= n 0) 0)
      ((= n 1) 1)
      (t (fib-inner 0 1 2)))))

The initial values are 0, 1 and 2, the base case is (= step n) and the step values are n-1, (+ n-2 n-1) and (1+ step). The function fib-inner is in tail position because there is no more computation after its invocation.

A quick remainder how do works:

(do ((a 1 (foo a))
     (b 3 (bar b)))
    ((= a b) 42)
  (side-effect! a b))

First assign to a and b the initial values 1 and 3, then check for the base case (= a b) and if true return 42, otherwise execute the body (side-effect! a b) and finally update a and b by assigning to them the step values (foo a) and (foo b). Then repeat from checking the base case. The last step could be equaled to an implicit tail-call of a function. Let's put it now in terms of the function we've defined earlier:

(defun fib** (n)
    ((= n 0) 0)
    ((= n 1) 1)
    (t (do ((n-2 0 n-1)
            (n-1 1 (+ n-2 n-1))
            (step 2 (1+ step)))
           ((= step n)
            (+ n-2 n-1))))))

This do form is a direct translation of the function fib-inner defined earlier.

I hope that you've enjoyed this short explanation. If you did then please let me know on IRC - my handle is jackdaniel @

Joe MarshallUpdate October 2021

· 7 days ago

Here's a few things I've been playing with lately.

jrm-code-project/utilities has a few utilities that I commonly use. Included are utilities/lisp/promise and utilities/lisp/stream which provide S&ICP-style streams (lazy lists). utilities/lisp/utilities is a miscellaneous grab bag of functions and macros.

jrm-code-project/homographic is a toolkit for linear fractional transforms (homographic functions). In addition to basic LFT functionality, it provides examples of exact real arithmetic using streams of LFTs.

jrm-code-project/LambdaCalculus has some code for exploring lambda calculus.

jrm-code-project/CLRLisp is an experimental Lisp based on the .NET Common Language Runtime. The idea is that instead of trying to adapt a standard Lisp implementation to run on the .NET CLR, we just add a bare-bones eval and apply that use the CLR reflection layer and see what sort of Lisp naturally emerges. At this point, it only just shows signs of life: there are lambda expressions and function calls, but no definitions, conditionals, etc. You can eval lists: (System.Console.WriteLine "Hello World."), but I haven't written a reader and printer, so it is impractical for coding.

Thomas FitzsimmonsMezzano on Librebooted ThinkPads

· 9 days ago

I decided to try running Mezzano on real hardware. I figured my Librebooted ThinkPads would be good targets, since, thanks to Coreboot and the Linux kernel, I have reference source code for all the hardware.

On boot, these machines load Libreboot from SPI flash; included in this Libreboot image is GRUB, as a Coreboot payload.

Mezzano, on the other hand, uses the KBoot bootloader. I considered chainloading KBoot from GRUB, but I wondered if I could have GRUB load the Mezzano image directly, primarily to save a video mode switch.

I didn’t want to have to reflash the Libreboot payload on each modification (writing to SPI flash is slow and annoying to recover from if something goes wrong), so I tried building a GRUB module “out-of-tree” and loading it in the existing GRUB. Eventually I got this working, at which point I could load the module from a USB drive, allowing fast development iteration. (I realize out-of-tree modules are non-ideal so if there’s interest I may try to contribute this work to GRUB.)

The resulting GRUB module, mezzano.mod, is largely the KBoot Mezzano loader code, ported to use GRUB facilities for memory allocation, disk access, etc. It’s feature-complete, so I released it to Sourcehut. (I’ve only tested it on Libreboot GRUB, not GRUB loaded by other firmware implementations.)

Here’s a demo of loading Mezzano on two similar ThinkPads:

GRUB Mezzano module demo

For ease of use, mezzano.mod supports directly loading the mezzano.image file generated by MBuild — instead of requiring that mezzano.image be dd‘d to a disk. It does so by skipping the KBoot partitions to find the Mezzano disk image. The T500 in the video is booted this way. Alternatively, mezzano.mod can load the Mezzano disk image from a device, as is done for the W500 in the video. Both methods look for the Mezzano image magic — first at byte 0 and, failing that, just after the KBoot partitions.

I added the set-i8042-bits argument because Coreboot does not set these legacy bits, yet Mezzano’s PS/2 keyboard and mouse drivers expect them; at this point Mezzano does not have a full ACPI device tree implementation.

Vsevolod DyomkinWatching a Model Train

· 10 days ago

Last week, I did a quick hack that quite delighted me: I added a way to visually watch the progress of training my MGL-based neural networks inside Emacs. And then people on twitter asked me to show the code. So, it will be here, but first I wanted to rant a bit about one of my pet peeves.


In the age of Jupyter and TensorBoard, adding a way to see an image that records the value of a loss function blinking on the screen — "huh, big deal" you would say. But I believe this example showcases a difference between low-tech and high-tech approaches. Just recently I chatted with one of my friends who is entering software engineering at a rather late age (30+), and we talked of how frontend development became even more complicated than backend one (while, arguably, the complexity of tasks solved on the frontend is significantly lower). And that discussion just confirmed to me that the tendency to overcomplicate things is always there, with our pop-culture industry, surely, following it. But I always tried to stay on the simple side, on the side of low-tech solutions. And that's, by the way, one of the reasons I chose to stick with Lisp: with it, you would hardly be forced into some nonsense framework hell, or playing catch-up with the constant changes of your environment, or following crazy "best practices". Lisp is low-tech just like the Unix command-line or vanilla Python or JS. Contrary to the high-tech Rust, Haskell or Java. Everything text-based is also low-tech: text-based data formats, text-based visualization, text-based interfaces.

So, what is low-tech, after all? I saw the term popularized by Kris De Decker from the Low-Tech Magazine, which focuses on using simple (perhaps, outdated by some standards) technologies for solving serious engineering problems. Most people, and the software industry is no exception, are after high-tech, right? Progress of technology enables solving more and more complex tasks. And, indeed, that happens. Sometimes, not always. Sometimes, the whole thing crumbles, but that's a different story. Yet, even when it happens, there's a catch, a negative side-effect: the barrier of entry rises. If 5 or 10 years ago it was enough to know HTML, CSS, and JavaScript to be a competent frontend developer, now you have to learn a dozen more things: convoluted frameworks, complicated deploy toolchains, etc., etc. Surely, sometimes it's inevitable, but it really delights me when you can avoid all the bloat and use simple tools to achieve the same result. OK, maybe not completely the same, maybe not a perfect one. But good enough. The venerable 80% solution that requires 20% effort.

Low-tech is not low-quality, it's low-barrier of entry.

And I would argue that, in the long run, better progress in our field will be made if we strive towards lowering the bar to more people in, than if we continue raising it (ensuring our "job security" this way). Which doesn't mean that the technologies should be primitive (like BASIC). On the contrary, the most ingenious solutions are also the simplest ones. So, I'm going to continue this argument in the future posts I'd like to write about interactive programming. And now, back to our hacks.

Getting to Terms with MGL

In my recent experiments I returned to MGL — an advanced, although pretty opinionated, machine learning library by the prolific Gabor Melis — for playing around with neural networks. Last time, a few years ago I stumbled when I tried to use it to reproduce a very advanced (by that time's standards) recurrent neural network and failed. Yet, before that, I was very happy using it (or rather, it's underlying MGL-MAT library) for running in Lisp (in production) some of the neural networks that were developed by my colleagues. I know it's usually the other way around: Lisp for prototyping, some high-tech monstrosity for production, but we managed to turn the tides for some time :D

So, this time, I decided to approach MGL step by step, starting from simple building blocks. First, I took on training a simple feed-forward net with a number of word inputs converted to vectors using word2vec-like approach.

This is the network I created. Jumping slightly ahead, I've experimented with several variations of the architecture, starting from a single hidden layer MLP, and this one worked the best so far. As you see, it has 2 hidden layers (l1/l1-l and l2/l2-l) and performs 2-class classification. It also uses dropout after each of the layers as a standard means of regularization in the training process.

(defun make-nlp-mlp (&key (n-hidden 100))
  (mgl:build-fnn (:class 'nlp-mlp)
    (in (->input :size *input-len*))
    (l1-l (->activation in :size n-hidden))
    (l1 (->relu l1-l))
    (d1 (->dropout l1 :dropout 0.5))
    (l2-l (->activation d1 :size (floor n-hidden 2)))
    (l2 (->relu l2-l))
    (d2 (->dropout l2 :dropout 0.5))
    (out-l (->activation d2 :size 2))
    (out (->softmax-xe-loss out-l))))

MGL model definition is somewhat different from the approach one might be used to with Keras or TF: you don't imperatively add layers to the network, but, instead, you define all the layers at once in a declarative fashion. A typical Lisp style it is. Yet, what still remains not totally clear to me yet, is the best way to assemble layers when the architecture is not a straightforward one-direction or recurrent, but combines several parts in nonstandard ways. That's where I stumbled previously. I plan to get to that over time, but if someone has good examples already, I'd be glad to take a look at those. Unfortunately, despite the proven high-quality of MGL, there's very little open-source code that uses it.

Now, to make a model train (and watch it), we have to pass it to mgl:minimize alongside with a learner:

(defun train-nlp-fnn (&key data (batch-size 100) (epochs 1000) (n-hidden 100)
                       (random-state *random-state*))
  (let ((*random-state* random-state)
        (*agg-loss* ())
        (opt (make 'mgl:segmented-gd-optimizer
                   :termination (* epochs batch-size)
                   :segmenter (constantly
                                (make 'mgl:adam-optimizer
                                      :n-instances-in-batch batch-size))))
        (fnn (make-nlp-mlp :n-hidden n-hidden)))
    (mgl:map-segments (lambda (layer)
                         (mgl:nodes layer)
                         :stddev (/ 2 (reduce '+ (mgl:mat-dimensions (mgl:nodes layer))))))
     `((:fn mgl:reset-optimization-monitors :period ,batch-size :last-eval 0)
       (:fn draw-test-error :period ,batch-size)))
    (mgl:minimize opt (make 'mgl:bp-learner
                            :bpn fnn
                            :monitors (mgl:make-cost-monitors
                                       fnn :attributes `(:event "train")))
                  :dataset (sample-data data (* epochs batch-size)))

This code is rather complex, so let me try to explain each part.

  • We use (let ((*random-state* random-state) to ensure that we can reproduce training in exactly the same way if needed.
  • mgl:segmented-gd-optimizer is a class that allows us to specify a different optimization algorithm for each segment (layer) of the network. Here we use the same standard mgl:adam-optimizer with vanilla parameters for each segment (constantly).
  • The following mgl:map-segments call is performing the Xavier initialization of the input layers. It is crucial to properly initialize the layers of the network before training or, at least, ensure that they are not all set to zeroes.
  • The next part is, finally, responsible for WATCHING THE MODEL TRAIN. mgl:monitor-optimization-periodically is a hook to make MGL invoke some callbacks that will help you peek into the optimization process (and, perhaps, do other needful things). That's where we insert our draw-test-error function that will run each batch. There's also an out-of-the-box cost-monitor attached directly to the mgl:bp-learner, which is collecting the data for us and also printing it on the screen. I guess, we could build the draw-test-error monitor in a similar way, but I opted for my favorite Lisp magic wand — a special variable *agg-loss*.
  • And last but not least, we need to provide the dataset to the model: (sample-adata data (* epochs batch-size)). The simple approach that I use here is to pre-sample the necessary number of examples beforehand. However, streaming sampling may be also possible with a different dataset-generating function.

Now, let's take a look at the function that is drawing the graph:

(defun draw-test-error (opt learner)
  ;; here, we print out the architecture and parameters of
  ;; our model and learning algorithm
  (when (zerop (mgl:n-instances opt))
    (describe opt)
    (describe (mgl:bpn learner)))
  ;; here, we rely on the fact that there's
  ;; just a single cost monitor defined
  (let ((mon (first (mgl:monitors learner))))
;; using some of RUTILS syntax sugar here to make the code terser
    (push (pair (+ (? mon 'counter 'denominator)
                   (if-it (first *agg-loss*)
                          (lt it)
                (? mon 'counter 'numerator))

(defun redraw-loss-graph (&key (file "/tmp/loss.png") (smoothing 10))
  (adw-charting:with-chart (:line 800 600)
    (adw-charting:add-series "Loss" *agg-loss*)
     (fmt "Smoothed^~a Loss" smoothing)
     (loop :for i :from 0
           :for off := (* smoothing (1+ i))
           :while (< off (length *agg-loss*))
           :collect (pair (? *agg-loss* (- off (floor smoothing 2)) 0)
                          (/ (reduce ^(+ % (rt %%))
                                     (subseq *agg-loss* (- off smoothing) off)
                                     :initial-value 0)
    (adw-charting:set-axis :y "Loss" :draw-gridlines-p t)
    (adw-charting:set-axis :x "Iteration #")
    (adw-charting:save-file file)))

Using this approach, I could also draw the change of the validation loss on the same graph. And I'll do that in the next version.

ADW-CHARTING is my goto-library when I need to draw a quick-and-dirty chart. As you see, it is very straightforward to use and doesn't require a lot of explanation. I've looked into a couple other charting libraries and liked their demo screenshots (probably, more than the style of ADW-CHARTING), but there were some blockers that prevented me from switching to them. Maybe, next time, I'll have more inclination.  

To complete the picture we now need to display our learning progress not just with text running in the console (produced by the standard cost-monitor), but also by updating the graph. This is where Emacs' nature of a swiss-army knife for any interactive workflow came into play. Surely, there was already an existing auto-revert-mode that updates the contents of a Emacs buffer on any change or periodically. For my purposes, I've added this lines to my Emacs config:

(setq auto-revert-use-notify nil)
(setq auto-revert-interval 6)  ; refresh every seconds

Obviously, this can be abstracted away into a function which could be invoked by pressing some key or upon other conditions occurring.

Nicolas HafnerPatch update, holidays, and the GIC - October Kandria Update

· 18 days ago

A shorter monthly update for once, as this included two weeks of holidays, in which we were both morally, legally, and bound by higher powers unbeknown to us forbidden from working on Kandria. Regardless, progress was made, and news are here to be shared, so an update was written!

Kandria Patch Update

A patch update is live that fixes the issues that were reported to us through the automated crash system. You can get the update from the usual link on the mailing list. I'm happy to say that there were not a lot of these to fix!

Of course, if you haven't yet had time to check out the new demo release, we hope you'll do so soon! We're always very excited to hear people's thoughts on what we have so far.


We don't have too much to show for this update, as we had a nice two weeks of holiday. I, for my part, spent some days down in Italy, which was really nice. Great weather for the most part, and it was great to have a proper change of scenery and schedule for once!

Because I'm me and can't help it, I did do some work as well during my holidays. I made some good progress on a project I've had in the slow cooker for years now, which will ultimately also be useful for Kandria, to support its modding system. But, more importantly to me, I finally got back into drawing more regularly again and made some pieces I'm actually quite happy with.

Wow! If what I wrote sounded any more confident, I'd have to mistake it for a toilet paper advertisement!

Game Industry Conference

Later this month is the Game Industry Conference, in which we'll be taking part. Once again, sponsored thanks to Pro Helvetia! I submitted a talk for the conference and actually got accepted for it as well, so I'll be presenting there in person. I don't know the exact date of my talk yet, but I'll be sure to announce it ahead of time on Twitter as soon as I do know.

If you're in Poland or are attending the conference yourself, let me know! I'd be happy to meet up!


This was a shorter month for me as I was on holiday for weeks. However, I've been researching key streamers and influencers that I'd previously highlighted for us, since they'd covered games similar to Kandria, and sending out emails to promote the new demo. Nick got some great feedback from Chris Zukowski on how to format these, which involved finding a hook in an influencer's content that I could latch onto, to show I'd actually engaged with their content. Nick also fed back on the horizontal slice quest designs I've been doing, which map out the rest of the narrative to the end of the game. This has been great to get some new eyes and steers on, and will help tighten up the content and manage the scope.

Fred & Mikel

These two have already started into content for the new areas. We're currently hashing out the look and feel, for which the second region is already getting close to final. We don't have any screenshots or music to show you yet though, you'll have to be a bit more patient for that.


As always, let's look at the roadmap from last month.

  • Fix reported crashes and bugs

  • Add telemetry to allow detecting problematic gameplay behaviour

  • Add more stats tracking for later achievements and ranking

  • Allow changing press actions to toggle actions in the input mapper

  • Add unlockable items and a fishing encyclopedia

  • Implement RPG mechanics for levelling and upgrades

  • Explore platforming items and mechanics

  • Practise platforming level design

  • Draft out region 2 main quest line levels and story

  • Draft out region 3 main quest line levels and story

  • Complete the horizontal slice

Oops! None of the items we had on there last time changed yet. But, some other important things were added and fixed already. Anyway, we'll start to get to the other things this month.

Until that's ready, I sincerely hope you give the new demo a try if you haven't yet. Let us know what you think if you do or have already!

Eric TimmonsNew Project: cl-tar

· 28 days ago

I have just published the first release of a new project: cl-tar. This was supposed to be my summer side-project, but it ran long as they often do :).

The goal of this project is to provide a Common Lisp interface to tar archives. It has its foundations in Nathan Froyd's archive library, but has been significantly extended and improved.


There are actually two subprojects under the cl-tar umbrella. The first is cl-tar-file, which provides the ASDF system and package tar-file. This project provides low-level access to physical entries in tar files. As a consequence, two tar files that extract to the same set of files on your filesystem may have two very different sets of entries of tar-file's point of view, depending on the tar format used (PAX vs ustar vs GNU vs v7).

The cl-tar-file project is technically a fork of archive. Except, all non-portable bits have been removed (such as code to create symlinks), better support for the various archive variants has been added, better blocking support added (tar readers/writers are supposed to read/write in some multiple of 512 bytes), cpio support removed, and a test suite added, along with other miscellaneous fixes and improvements.


The second sub project is cl-tar itself, which provides three ASDF systems and packages: tar, tar-simple-extract, and tar-extract.

The tar system provides a thin wrapper over the tar-file system that operates on logical entries in tar files. That is, a regular file is represented as a single entry, no matter how many entries it is composed of in the actual bits that get written to the tar file. This system is useful for analyzing a tar file or creating one using data that is not gotten directly from the file system.

The tar-simple-extract system provides a completely portable interface to extract a tar archive to your file system. The downside of portability is that there is information loss. For example, file owners, permissions, and modification times cannot be set. Additionally, symbolic links cannot be extracted as symbolic links (but they can be dereferenced).

The tar-extract system provides a more lossless extraction capability. The downside of being lossless is that it is more demanding (osicat must support your implementation and OS) and it raises security concerns.

A common security concern is that a malicious tar file can extract a symlink that points to an arbitrary location in your filesystem and then trick you into overwriting files at the location by extracting later files through that symlink. This system tries its best to mitigate that (but makes no guarantees), so long as you use its default settings. If you find a bug that allows an archive to extract to an arbitrary location in your filesystem, I'd appreciate it if you report it!

Also note that tar-extract currently requires a copy of osicat that has the commits associated with this PR applied.

next steps

First, close the loop on the osicat PR. It started off as a straightforward PR that just added new functions. However, when I tested on Windows, I realized I couldn't load osicat. So I added a commit that fixed that. There may be some feedback and changes requested on how I actually acomplished that.

Second, integrate tar-extract into CLPM. CLPM currently shells out to a tar executable to extract archives. I'd like to use this pure CL solution instead. Plus, using it with CLPM will act as a stress test by exposing it to many tar files.

Third, add it to Quicklisp. tar-extract won't compile without the osicat changes, so those definitely need to be merged first. Additionally, I want to have at least some experience with real world tar files before making this project widely available.

Fourth, add support for creating archives from the filesystem.

Fifth, add the ability to compile to an executable so you could use this in place of GNU or BSD tar :).

If the fourth and fifth steps excite you, I'd love to have your help making them a reality! They're not on my critical path for anything at the moment, so it'll likely be a while before I can get to them.

Eric TimmonsCLPM 0.4.0 released

· 38 days ago

I have tagged CLPM 0.4.0 and posted the build artifacts at This release brings quite the laundry list of bug fixes and enhancements, including the much awaited Mac M1 support. The full changelog summary is below the break.

Additionally, the burgeoning CLPM community now has more spaces to interact. If you're interested in learning about or getting help on CLPM, I encourage you to join #clpm on We have a Matrix room as well (, but the Libera room is currently more active and preferred.

If you are already using CLPM, I encourage you to subscribe to the clpm-announce mail list. This is a low traffic list where new releases will be announced.

  • Changed layout of release tarballs.
  • Published tarballs now contain a static executable (#11).
  • No longer using the deploy library to build releases (#15 #11).
  • Updated build script to more easily build static or dynamic executables (#11).
  • Fixed bug in computing the source-registry.d file for the clpm client (#16)
  • Starting to build up a test suite (#3)
  • Added automated testing on Gitlab CI.
  • Added clpm-client:*activate-asdf-integration* to control default integration with ASDF upon context activation.
  • The default directories for CLPM cache, config, and data have changed on Windows. They are now %LOCALAPPDATA%\clpm\cache\, %LOCALAPPDATA%\clpm\config\, and %LOCALAPPDATA%\clpm\data\.
  • Added new config option (:grovel :lisp :command). This string is split via shlex into a list of arguments that can be used to start the child lisp process.
  • Deprecated (:grovel :lisp :path) in favor of (:grovel :lisp :command).
  • Added new value for (:grovel :lisp :implementation) - :custom. When :custom is used, no arguments are taken from the lisp-invocation library, the user must specify a command that completely starts the child lisp in a clean state.
  • Better support for using MSYS2's git on Windows.
  • Support for Mac M1 (#20).
  • Fixed bug causing groveling to take an inordinately long time for systems with :defsystem-depends-on or direct calls to asdf:load-system in their system definition files (!9).
  • Fixed bug causing unused git and asd directives to linger in clpmfile.lock (#32).
  • Add support for bare git repos in clpmfile (not from Github or Gitlab) (#22).
  • Add clpmfile :api-version "0.4". Remains backwards compatible with 0.3. (#22).
  • Fix bug saving project metadata on Windows.
  • Fix client's UIOP dependency to better suit ECL's bundled fork of ASDF.
  • Fix issue READing strings in client from a lisp that is not SBCL (#13).
  • Parse inherited CL_SOURCE_REGISTRY config in client using ASDF (#14).

Nicolas Hafner0.2.2 Demo Release, Gamescom & more - September Kandria Update

· 46 days ago

Big news this month: there's a new free demo release (!!), news on the Pro Helvetia grant and on Gamescom, and a lot of stuff to look at that we worked on!

0.2.2 Demo Release

There's a new demo release for Kandria that you can now get for free! If you're on our mailing list, you should have gotten a download link already. There's a lot of changes for this version since the last release in April, but let me highlight a few of the big ones:

  • Major revisions to all the dialogue and quest logic to make it flow better

  • A proper tutorial sequence to introduce the controls and the game's world

  • UI for everything, including a map, main menu, quest log, etc

  • A new fishing minigame to relax and take in the world

  • Major changes to the combat to improve the flow and feel

  • Lots and lots of bugfixes and tweaks based on user feedback. Thank you!

  • Custom sound effects for everything

  • Custom music, including horizontal mixing of music tracks!

The game is now not only on Steam, but also on, if you prefer to follow updates on that platform!

Again, to get the new demo, sign up here:

Pro Helvetia Grant

The Pro Helvetia Interactive Media Grant deadline was on the 1st, and we've submitted our stuff for it! I'm quite happy with the game design pitch doc that we put together, but since there's probably quite a few very capable studios applying for the grant, who knows whether we'll have any luck with it.

I'm definitely keeping my fingers crossed for it, as getting the grant would not only be very important for us financially, but also be a huge boost in confidence, to have support like that. It would also make negotiations with publishers easier, as another organisation has then already given their vote of confidence. Getting the first foot in the door like that is always the hardest!

Anyway, it'll probably take a few months before we know anything, so there's no point in worrying about the result of it now, we'll just keep on trucking in the meantime.

Gamescom, Devcom, IndieArenaBooth

So, Gamescom was this month, which took up a week with meetings and such. We've contacted a bunch of publishers and met with a few that expressed interest in Kandria as well, which is cool. I'm not expecting anything of course, competition in this area is extremely fierce, but it's nice that we're at least getting warm receptions and actual interest.

They'll look at the new demo release now and hopefully get back to us on what they think of the game in the next few weeks. We'll be sure to let you know if we hear anything about that!

Aside from that, Kandria and Eternia both were part of the Steam listing for Gamescom, which gave us a nice spike on our wishlist numbers:

We definitely need a bunch more spikes like that though, so I'm keeping my eyes open for other festival opportunities like that!


This month was a "UI month" and as such there's a lot of changes for that. Overall I'm really glad we had time for this finally, as it really improved the overall polish of the game by a lot.

There's now a main menu and load screen:

A handy shop UI:

An in-game map showing you where you and NPCs are, as well as where you've gone:

Finally a way to change key mappings to your liking:

And all sorts of other improvements to things like the item menu, options menus, etc.


Since this was the last month before the Pro Helvetia submission and new demo, I've spent a lot of time playtesting the questline, reporting and fixing bugs, and just polishing the content as much as possible - such as adding descriptions for all items and fish, and a first-pass economy for when you buy/sell with Sahil. I also proofed Nick's pitch doc and did a little market research for this on similar games. Since we want to make a bit of a fuss over this new demo, I've also researched into reddit and prepped a couple of stories, which we could post to announce the release.

Since Gamescom also happened this month, I filtered the list of attending publishers and researched them, trying to find those who'd be most suitable for our game. Nick was then able to use this to prioritise meetings.

Finally, I've started to look beyond the demo to the horizontal slice, which we're planning to tackle next. We'd already done some work outlining the remaining acts of the story (the current demo is essentially act 1 of 5), writing some backstory and lore for the other factions and regions (which Fred has been concepting); but now we need to bring these acts to life with actual mainline quest content. I'm still in the middle of this, but I've already made a good start at planning out the main quests for acts 2 and 3. Next I'll be getting feedback on these from the team, but already it's nice to be pushing back the fog of war, and defining the rest of the story in more concrete terms.


Fred's been working on the horizontal slice content already, doing concept work for the second and third areas:

We're trying to keep all the areas very visually distinct, and I think that's working out quite well so far! I'm really excited to see it in-game.


Mikel's got all the necessary tracks for the demo finished in record time, and in the past week has been going over all of them to revise them and make them fit even better to the game's feel. Here's some of the tracks:

These tracks have many variants still to adapt to the mood of the game at the moment, so there's a lot more work behind this than might first be apparent!


Cai's been hard at work implementing all the needed sound effects that I'd been slacking on so far. We now have sounds for almost every interaction in the game, and it has contributed a ton to make the game feel more alive. We even have stuff like distinguished footsteps based on the terrain you're walking on.

There's still a few revisions left to be done, but otherwise this first batch of sounds got done really well. We'll probably wait a bit more until we do another batch, as we have to focus on actually making some more content, first.


And with that, let's look at the roadmap from last month with the updates from this month added on top:

  • Implement a main menu, map, and other UI elements

  • Implement a load screen and fix UI issues

  • Create and integrate new sound effects for 90% of the interactions in the game

  • Start work on the horizontal slice

  • Complete and revise all the music tracks for the current regions

  • Update marketing materials like the capsule image

  • Start work on modding integration

  • Implement RPG mechanics for levelling and upgrades

  • Explore platforming items and mechanics

  • Practise platforming level design

  • Draft out region 2 main quest line levels and story

  • Draft out region 3 main quest line levels and story

  • Complete the horizontal slice

But, before we get to all that we got a well deserved two weeks of holidays ahead of us. Once we're all back though, I'm sure we'll get that horizontal slice knocked out in no time!

In the meantime, I sincerely hope you give the new demo a try, and let us know what you think if you do!

Eric TimmonsToward a New CL Project Index

· 46 days ago

Quicklisp has had a profound impact on the CL community. It's transformed the way CL devs share libraries, made it easier and encouraged devs to re-use existing code instead of implementing everything in house, and is widely used. While Quicklisp took the CL community a huge step forward, I nevertheless think we can and should do better.

To that end, I've been working on two interlinked projects, CLPM and the Common Lisp Project Index (CLPI). I've posted about CLPM in various places before and awareness of it is already growing in the CL community. Therefore, this post will focus on CLPI and why I think it is important. My ultimate goal is to find like-minded people to collaborate with on bringing CLPI (or something similar) to reality.

I've been meaning to make a post like this for a while, but life kept putting it on the back burner. However, I've recently found more CLPM users in the wild, which always gets my energy levels up for this type of work. Plus, discussions I've seen in various Lisp forums (including this tweet that was brought to my attention) have made me think that the time may finally be ripe to start discussing this topic more broadly.

Before continuing, I want to make clear that I have the utmost respect for Xach, Quicklisp, and the services he provides to the community. This post does critique what is probably Xach's most well known work, but it is by no means an attack against either QL or him and I will not tolerate any comments or discussion that cross that line.

What is a Project Index?

First, let's clarify at a high level what I mean by a project index. Basically, a package index is a listing of projects and ASDF systems. For every project, it contains information on what releases are available (how to actually get the code), along with what systems are included in each release and what the dependencies of those systems are.

A project index lets you quickly answer questions like "what is the latest version of cffi?", "what are the dependencies of the latest version of cffi?", or "where can I download the latest version of ironclad?" without needing to load any code.

Quicklisp Issues

Now let's look at what I consider to be flaws of the Quicklisp project index model.

  1. Conflation of project manager and project index. When I mention Quicklisp, what do you think of first? Perhaps the quicklisp-client that gets loaded into your image and provides ql:quickload? Or is it the distinfo.txt, systems.txt, and releases.txt files that contain all the projects known to Quicklisp?
    The problem is that it's both! I think that there needs to be a clear separation between the project index (distinfo.txt and friends) and the consumers of the project index (quicklisp-client). Such a separation both makes it clearer to what is being referred in casual conversation, and makes it easier to build competing consumers or servers of the project index.

  2. The project index format is not documented. I believe this is a consequence of the previous issue. To the best of my knowledge, the only documentation of the QL project index format is the quicklisp client code that interacts with it. This makes it harder to implement both competing clients (I had to do quite a bit of code diving to get CLPM to understand the QL project index) and competing servers (there exist several forks of the quickdist project, yet none of them seem to create the dist versions file that CLPM needs).

  3. Not a lot of data is provided. The QL project index does not contain critical information, such as license, ASDF system version number, location of the canonical VCS repo, or author names.

  4. Not easily extensible. The only way to include more information in a QL project index is to add more files. Information cannot be added to releases.txt nor systems.txt without breaking the QL client. Additionally, if the current aesthetics are to be maintained, each line in a file must represent one entry that consists of tokens to be interpreted as strings, integers, or a list of strings (but only one list per entry).

  5. Enforces a particular style of development. A QL project index is rolling: it always grabs the latest version of projects. This forces projects to always use the latest and "greatest" (scare quotes intended) versions of their dependencies or risk being cut from the index. Additionally, it makes it difficult for developers to continue supporting old versions of their code that they would like to maintain; if version 1.0.0 of system A is released, then version 2.0.0, followed by 1.1.0, version 1.1.0 will never show up in a QL project index.

  6. Takes control of releases away from developers. Not only does the QL project index preclude releasing bug fixes to older, stable code, it also takes away the choice of when to perform a release. A developer cannot say "oh crap, I just realized 1.0.0 had a huge bug, I need to get 1.0.1 out today!", instantly publish 1.0.1, and then have others immediately use it. Instead, they have to wait until the next time the QL project index maintainer decides to poll them and see if a new version is available. For the primary QL index, this process can take about a month.

  7. The index is not space efficient. There is a lot of duplicated information in a QL project index. If a project had new releases in QL version M and N, then the information for the release in version M is replicated identically for releases M through N-1. This is an issue if you want to make a consumer that can show when things changed, can install any version of a project, or just wants to efficiently sync index data over the internet.


A side note on Ultralisp. Ultralisp largely seeks to address issue 6. However, as far as I can tell, it still polls, so developers cannot push new versions to it on demand (please correct me if I'm wrong here!). However, even if it does allow pushes, it still falls victim to the all the other issues except 1. Additionally, Ultralisp is very affected by issue 7 given its update frequency.


To address these concerns, I've been slowly developing the Common Lisp Project Index (CLPI) specification. Additionally, I currently have two instances of the index running. One mirrors the data available in the primary QL index, the other is for internal use with my coworkers. Last, CLPM can efficiently consume an index that follows the CLPI spec.

I'm not claiming that CLPI is perfect, but I think it is a significant step forward from QL project indices. Plus, I have some experience running it so I also know that it works (albeit for relatively small audiences). The QL mirror is located at

Now, let's take a brief dive into each of the issues I raised with the QL project index and see how CLPI addresses them.

Conflation of project manager and project index

There is no project manager named CLPI. I do not ever plan on creating one. In any case, Common Lisp Project Index would be a weird name for a project manager.

The project index format is not documented

The current specification of the format of CLPI indices is located at

The current object model used by CLPI is located at

Not a lot of data is provided

CLPI allows a project's canonical VCS to be provided. Each system can have the author, license, description, and version specified. System dependencies can include ASDF's (:version ...) and (:feature ...) specifiers.

Not easily extensible

Every file must contain one or more forms that are suitable for READing. Additionally, all the non trivial files consist of plists. This makes it trivial to both write a parser for each file and to extend files with extra information without breaking consumers (so long as the extra information does not change the semantics on which older versions are relying).

Enforces a particular style of development

Every release of every project is made available. Additionally, with the preservation of (:version ...) specifiers from ASDF's dependency lists, developers can easily provide version constraints and project managers can also take those constraints into account.

Takes control of releases away from developers

The proof of concept CLPI server I have developed for my internal use allows a developer to push releases on demand. I am using this in conjunction with Gitlab CI to push releases when tags are created on our git repos.

The index is not space efficient

CLPI borrows a lot of ideas from Rubygems' compact_index. While it is not required as part of the spec, CLPI instances can signal that they intend to only append to the files served to consumers. This lets consumers easily use HTTP headers to download only the new parts of each file that they have yet to see.

Additionally, instead of a monolithic file like releases.txt that contains release information, CLPI splits this info into project specific files. For example, you can get all the known releases for fiveam by downloading To do the same thing with a QL index, you'd have to download releases.txt for every dist version (currently 117 in the primary QL index). For comparison, the CLPI file is currently 2183 bytes, while a single releases.txt file (from the 2021-08-07 dist) is 506134 bytes, or over 200 times bigger. Additionally, the CLPI version also tells you the dependencies. To get that from QL, you also need to download systems.txt (the 2021-08-07 version is 374391 bytes).

Next Steps

Does CLPI excite you? Do you want it to become reality? Awesome, I'd love to collaborate with you to bring CLPI or something similar to the CL community at large! Please reach out to me here, on #commonlisp or #clpm on (I'm etimmons), on Matrix at (I'm, or via email at

There's a lot to do and I really want to make this a community effort.

  • I'd love it people could provide feedback on both the object model and the index format!

  • I'd love to work with people excited to help take my proof of concept CLPI server and make it production ready (or just make a new one from scratch)! This would include implementing a database backend, support for multiple users, and a permissions system.

  • I'd love to work with others interested in standing up a CLPI server for the whole community to craft a set of community guidelines and policies that address concerns such as when and how projects can be pulled (remember NPM's leftpad incident??), project ownership, etc!

  • I'd love to have feedback from all the people out there that are unsatisfied by both the QL client and CLPM! If you're making your own project manager, is there anything we can do with the CLPI spec to make your life easier? Do you have something like CLPI that we can learn from/build off?

  • But perhaps most of all, I'd love to hear if developers would be interested in publishing their code to a community CLPI server! This is one place where QL's model shines. Xach does all the work, so it is nearly effortless for individual developers to get their latest releases into the QL index. Under the CLPI model, someone (ideally the developer, but potentially a proxy maintainer) would have to perform an action on every release to get it into the CLPI instance.

It's likely that I'll continue putzing along with CLPI, even if I don't get any help. But it'll likely never get to the point of being usable by the community at large without input from others. And even if I somehow managed to get a CLPI server that is usable by the whole community, I wouldn't host it without a team willing to help maintain it, both policy- and tech-wise. I run enough projects with a bus factor of one as it is.

Eric TimmonsCLPM 0.4.0-rc.1 Available

· 47 days ago

I have just tagged CLPM 0.4.0-rc.1 and posted the build artifacts at Assuming there are no show stoppers discovered, I plan to release v0.4.0 next weekend.

This release will bring quite the laundry list of bug fixes and enhancements, including the much awaited Mac M1 support. The complete list (at this point in time) is included below.

But first, I want to inform you that I plan on getting v0.5.0 out the door ASAP. And that 0.5 will likely include some breaking changes to clpmfiles. For more information, see this issue. The breaking change is necessary to fix issue 39 and will in general lead to CLPM being cleaner and faster.

Additionally, the two other big ticket features I plan to add are groups inside clpmfiles (e.g. you can have dependencies that are only installed for dev/testing purposes) and support for versioning ASDF/UIOP in bundles. The latter change is going to be difficult due to both ASDF being a dependency of clpm-client and the special relationship the UIOP and ASDF enjoy. However, I have most of a plan and think it will be feasible without placing too much of a burden on the end user.

I would have liked to include all of these changes in v0.4, but I've been sitting on v0.4 for a long time, have been telling enough people variants of "use the latest v0.4 alpha, it's good to go except M1 support!", and I told people to use v0.4 along with my demo paper (page 21) at ELS '21. So I'd feel pretty bad about breaking clpmfiles at the moment.

If you like CLPM, have feedback, or just want to chat about it, please join us on Matrix (preferred) or #clpm on

The current changelog entry for v0.4.0 is:

  • Changed layout of release tarballs.
  • Published tarballs now contain a static executable (#11).
  • No longer using the deploy library to build releases (#15 #11).
  • Updated build script to more easily build static or dynamic executables (#11).
  • Fixed bug in computing the source-registry.d file for the clpm client (#16)
  • Starting to build up a test suite (#3)
  • Added automated testing on Gitlab CI.
  • Added clpm-client:*activate-asdf-integration* to control default integration with ASDF upon context activation.
  • The default directories for CLPM cache, config, and data have changed on Windows. They are now %LOCALAPPDATA%\clpm\cache\, %LOCALAPPDATA%\clpm\config\, and %LOCALAPPDATA%\clpm\data\.
  • Added new config option (:grovel :lisp :command). This string is split via shlex into a list of arguments that can be used to start the child lisp process.
  • Deprecated (:grovel :lisp :path) in favor of (:grovel :lisp :command).
  • Added new value for (:grovel :lisp :implementation) - :custom. When :custom is used, no arguments are taken from the lisp-invocation library, the user must specify a command that completely starts the child lisp in a clean state.
  • Better support for using MSYS2's git on Windows.
  • Support for Mac M1 (#20).
  • Fixed bug causing groveling to take an inordinately long time for systems with :defsystem-depends-on or direct calls to asdf:load-system in their system definition files (!9).
  • Fixed bug causing unused git and asd directives to linger in clpmfile.lock (#32).
  • Add support for bare git repos in clpmfile (not from Github or Gitlab) (#22).
  • Add clpmfile :api-version "0.4". Remains backwards compatible with 0.3. (#22).
  • Fix bug saving project metadata on Windows.
  • Fix client's UIOP dependency to better suit ECL's bundled fork of ASDF.
  • Fix issue READing strings in client from a lisp that is not SBCL (#13).
  • Parse inherited CL_SOURCE_REGISTRY config in client using ASDF (#14).

Joe MarshallTail recursion and fold-left

· 52 days ago

fold-left has this basic recursion:

(fold-left f init ())      = init
(fold-left f init (a . d)) = (fold-left f (f init a) d)
A straightforward implementation of this is
(defun fold-left (f init list)
  (if (null list)
      (fold-left f (funcall f init (car list)) (cdr list))))
The straightforward implementation uses a slightly more space than necessary. The call to f occurs in a subproblem position, so there the stack frame for fold-left is preserved on each call and the result of the call is returned to that stack frame.

But the result of fold-left is the result of the last call to f, so we don't need to retain the stack frame for fold-left on the last call. We can end the iteration on a tail call to f on the final element by unrolling the loop once:

(defun fold-left (f init list)
  (if (null list)
      (fold-left-1 f init (car list) (cdr list))))

(defun fold-left-1 (f init head tail)
  (if (null tail)
      (funcall f init head)
      (fold-left-1 f (funcall f init head) (car tail) (cdr tail))))

There aren't many problems where this would make a difference (a challenge to readers is to come up with a program that runs fine with the unrolled loop but causes a stack overflow with the straightforward implementation), but depending on how extreme your position on tail recursion is, this might be worthwhile.

Joe MarshallA Floating-point Problem

· 55 days ago

Here's a 2x2 matrix:

[64919121   -159018721]
[41869520.5 -102558961]
We can multiply it by a 2 element vector like this:
(defun mxv (a b
            c d


  (funcall receiver
           (+ (* a x) (* b y))
           (+ (* c x) (* d y))))

* (mxv 64919121     -159018721
       41869520.5d0 -102558961


(35738642 2.30496005d7)
Given a matrix and a result, we want to find the 2 element vector that produces that result. To do this, we compute the inverse of the matrix:
(defun m-inverse (a b
                  c d

  (let ((det (- (* a d) (* b c))))
    (funcall receiver
             (/ d det) (/ (- b) det)
             (/ (- c) det) (/ a det))))
and multiply the inverse matrix by the result:
(defun solve (a b
              c d


  (m-inverse a b
             c d
             (lambda (ia ib
                      ic id)
               (mxv ia ib
                    ic id

So we can try this on our matrix
* (solve 64919121     -159018721
         41869520.5d0 -102558961


(1.02558961d8 4.18695205d7)
and we get the wrong answer.

What's the right answer?

* (solve 64919121         -159018721
         (+ 41869520 1/2) -102558961


(205117922 83739041)
If we use double precision floating point, we get the wrong answer by a considerable margin.

I'm used to floating point calculations being off a little in the least significant digits, and I've seen how the errors can accumulate in an iterative calculation, but here we've lost all the significant digits in a straightforward non-iterative calculation. Here's what happened: The determinant of our matrix is computed by subtracting the product of the two diagonals. One diagonal is (* 64919121 -102558961) = -6658037598793281, where the other diagonal is (* (+ 41869520 1/2) -159018721) = -6658037598793280.5 This second diagonal product cannot be represented in double precision floating point, so it is rounded down to -6658037598793280. This is where the error is introduced. An error of .5 in a quantity of -6658037598793281 is small indeed, but we amplify this error when we subtract out the other diagonal. We still have an absolute error of .5, but now it occurs within a quantity of 1, which makes it relatively huge. This is called “catastrophic cancellation” because the subtraction “cancelled” all the significant digits (the “catastrophe” is presumably the amplification of the error).

I don't care for the term “catastrophic cancellation” because it places the blame on the operation of subtraction. But the subtraction did nothing wrong. The difference betweeen -6658037598793280 and -6658037598793281 is 1 and that is the result we got. It was the rounding in the prior step that introduced an incorrect value into the calculation. The subtraction just exposed this and made it obvious.

One could be cynical and reject floating point operations as being too unreliable. When we used exact rationals, we got the exactly correct result. But rational numbers are much slower than floating point and they have a tendancy to occupy larger and larger amounts of memory as the computation continues. Floating point is fast and efficient, but you have to be careful when you use it.

Joe MarshallFold right

· 64 days ago

fold-left takes arguments like this:

(fold-left function init list)
and computes
* (fold-left (lambda (l r) `(f ,l ,r)) 'init '(a b c))
(F (F (F INIT A) B) C)
Notice how init is the leftmost of all the arguments to the function, and each argument appears left to right as it is folded in.

Now look at the usual way fold-right is defined:

(fold-right function init list)
It computes
* (fold-right (lambda (l r) `(f ,l ,r)) 'init '(a b c))
(F A (F B (F C INIT)))
although init appears first and to the left of '(a b c) in the arguments to fold-right, it is actually used as the rightmost argument to the last application.

It seems to me that the arguments to fold-right should be in this order:

; (fold-right function list final)
* (fold-right (lambda (l r) `(f ,l ,r)) '(a b c) 'final)
(F A (F B (F C FINAL)))
The argument lists to fold-left and fold-right would no longer match, but I think switching things around so that the anti-symmetry of the arguments matches the anti-symmetry of the folding makes things clearer.

Quicklisp newsAugust 2021 Quicklisp dist update now available

· 75 days ago

 New projects

  • cache-while — A Common Lisp macro for defining temporary caches that invalidate based on expressions evaluating to different values. — LLGPL
  • cl-coinpayments — Helpers for working with the api. — MIT
  • cl-drawille — cl-drawille: Drawing in terminal with Unicode Braille characters. — MIT
  • cl-sha1 — SHA1 Digest and HMAC for LispWorks. — Apache 2.0
  • cl-webdriver-client — cl-webdriver-client is a binding library to the Selenium 4.0 — MIT
  • clj-con — Implements Clojure-styled concurrency operations such as `future` and `promise`. — MIT
  • clj-re — Implements Clojure-styled regexp operations such as `re-matches` and `re-find`. — MIT
  • depot — Protocol for transparent collections of files. — zlib
  • fof — Enable rapid file search, inspection and manipulation — GPL3+
  • hash-table-ext — Tiny extensions for common lisp hash-tables. — MIT
  • hunchenissr-routes — Better routes to be used with Hunchenissr. — LLGPL
  • omglib — A Common Lisp library to build fully dynamic web interfaces — GPL3
  • query-repl — REPL for user query. — MIT
  • slite — SLIME based Test-runner for FiveAM tests (and possibly others in the future) — Apache License, Version 2.0
  • with-c-syntax — with-c-syntax is a fun package which introduces the C language syntax into Common Lisp. — WTFPL

Updated projects: 3d-vectors, alexandria, also-alsa, april, architecture.builder-protocol, bdef, caveman, check-bnf, chipz, chirp, cl+ssl, cl-ana, cl-collider, cl-cuda, cl-debug-print, cl-environments, cl-form-types, cl-gamepad, cl-gserver, cl-i18n, cl-kraken, cl-las, cl-liballegro, cl-migratum, cl-mixed, cl-opencl, cl-opencl-utils, cl-patterns, cl-ses4, cl-sse, cl-utils, cl-webkit, clack, clem, clog, closer-mop, cmd, colored, command-line-arguments, common-doc, common-html, common-lisp-jupyter, consfigurator, core-reader, croatoan, cserial-port, cytoscape-clj, dartscluuid, data-frame, dexador, dfio, drakma, drakma-async, file-attributes, flexi-streams, gendl, generic-cl, harmony, imago, introspect-environment, jingoh, kekule-clj, lack, lisp-binary, lisp-stat, lispbuilder, lyrics, markup, mcclim, mito, mnas-package, mnas-string, mutility, neural-classifier, null-package, nyxt, overlord, parachute, petalisp, portable-condition-system, postmodern, prompt-for, qlot, quickutil, quilc, read-as-string, rove, sanity-clause, screamer, sel, serapeum, shasht, shop3, sketch, sly, snappy, snooze, special-functions, speechless, static-dispatch, stumpwm, tailrec, ten, tfeb-lisp-hax, tfeb-lisp-tools, trestrul, trivial-ed-functions, trivial-inspector-hook, ufo, uiop, uncursed, vellum, vellum-csv, vgplot, vk, websocket-driver, whirlog, zacl.

Removed projects: lucerne

To get this update, use (ql:update-dist "quicklisp"). Enjoy!

Nicolas HafnerGDC, fighting, and more - August Kandria Update

· 82 days ago

A big ole update for Kandria this month!


One of the main events this month was GDC. This was my first time attending, and I'm really glad that I was offered the chance to with the great support by Pro Helvetia and SwissNex. Thank you very much again for all of your support this year!

The highlight of the event for me were the daily video networking sessions, where you were led onto a virtual floor with a bunch of tables. Each table could seat up to six people and you'd chat over audio and video. It was really cool to hang out and chat with fellow attendees about... well, pretty much whatever!

What wasn't so cool about those sessions, was that they only lasted for an hour, at the end of which you were unceremoniously booted out, without even the ability to see who you were at the table with, nor the accompanying text chat. I do not understand at all why that platform was not just up throughout the entirety of the conference. It's not like there were ever that many people there to begin with, I never saw the total number rise above 120.

With regards to the booth that we had at the Swiss country pavilion, that unfortunately turned out to be almost pointless. Everyone I talked to at the virtual meet wasn't even aware that booths existed at all, let alone the ones in the country pavilions. Being buried under ten links almost guaranteed that we wouldn't be found except by the most vigilant. It isn't surprising then that we didn't get any contact requests through the booth's message box.

I'm really confused as to why they had practically zero visibility for the showfloors and booths. It seems to me that those are a rather large part of a usual conference, so advertising them so poorly is strange. I can't even imagine what SwissNex had to pay to get our booths set up, and I feel sorry for what they got for that.

I hope that next year the presentation is going to be better, as for the amount of money involved in the tickets and everything, I have to say I'm quite disappointed with the GDC organisers. We'll see how Gamescom goes next month, I suppose.

Combat developments

This month was meant to be devoted to combat revisions. I did get a number of those done, so movement is now a lot more satisfying and you can actually juggle enemies in the air:

However, due to the mass of feedback amounted by the playtesting, GDC interruptions, and my general reluctance to work on it there hasn't been as much progress as I would like. I'll definitely have to revisit this again later down the road. In the very least though I feel like we have the features required in the engine now to make the system work well, it's "just" down to tweaking the parameters.

To give you some perspective on why tweaking of these parameters is a pain though, let me show you a screenshot of our in-house animation editor:

For each frame (the player has around 700 frames of animation at this point), you can set a mass of different properties that change combat behaviour and movement. Tweaking them one by one, performing the attack, going back to tweak it again, and repeating that is an extremely arduous process.

I tried my best to keep at it throughout the month, but the tedium of it made it quite difficult. I hope I can instead gradually improve it with time.

UI look and feel

I've taken some time to change the look and feel of the UI in the game. Most notably the button prompts now look a lot better than they used to. The fishing minigame shows that best:

The textbox also got a revision and it's now capable of doing text effects:

Aside from those tweaks there were a myriad of changes from the further blind playtest sessions as well.

Eternia update

A new update for Eternia: Pet Whisperer was rolled out. This update took two days to put together and includes important stability fixes for MacOS and Windows users. On MacOS the behaviour on Retina displays is improved and audio output on devices with samplerates above 44.1kHz has been fixed. General performance has also been improved. On Windows spurious crashes caused by antivirus software should now no longer occur.

Eternia will also likely be on sale during the upcoming Gamescom Steam sale, so keep an eye out for that!


This month has been about press and polish. With GDC happening, I helped prioritise the press list and reach out to the most relevant people; we didn't get a huge response, which isn't unexpected (press are inundated at the best of times, never mind during GDC) - but it's been encouraging to get some replies; and most importantly, it's getting the game on peoples' radars.

I've also been working through tons of feedback Nick has gathered from blind playtests of the game, using it to make the quests easier to understand and more accessible: finessing spawn locations, clarifying objectives more in dialogue, etc. I ran a few tests myself, and it's amazing how things you thought were obvious sometimes don't translate to the player. A highlight was watching my brother return to the surface after the first quest: he didn't know the rest of the settlement was over to the right, and instead went left, all the way back to the tutorial area; since Catherine was following him at the time, it re-triggered all her tutorial dialogue! Noooooooooo! (But in a good way :) )

Nick also made some cool new features like random spawners that can add a myriad of world-building items to the levels (and which later you'll be able to sell to Sahil); I spent time organising and placing these. Also, text effects and colouring! I went a bit bananas with this at first, using the swirly rainbow effect right off the bat in the tutorial, when Catherine gets excited; to be fair it's probably the only point in the game I could've justified using it. But I've since toned things back, as although the game has quirk, we need to watch the tone and make sure we don't go too cartoony. I've also established a basic visual language for using these effects and colours (hint: sparingly).


Fred has been working on new sets of animations and some concept work. Some of the new animations are for expanded combat moves, so there's now a heavy and light charge attack:


Mikel finished a couple more tracks, well on ... track to make the September release date with all the music for the current areas included! These tracks are for the camp area, and as such convey a more chill atmosphere:

Aside from the music there's also been more audio changes, by way of a new team member:


I'm Cai, I'm a Sound Designer for video games. I've been in the industry for 2 years! I focus on making impactful, meaningful sounds that help to immerse the player in the world we create! Kandria is a really exciting project to be involved with! The story and atmosphere of the game are both compelling and exciting so I'm thrilled to have the opportunity to contribute to this through the sound!

Cai has been hard at work remaking the existing sounds and adding new ones. One of the bigger changes in that respect is the addition of atmospheric sound layers that now underlay each music track. The atmospherics and music both change independently depending on the area the player is currently in.

It still needs some tuning, though. We need to make sure the loudness levels of each track work properly in conjunction with the atmospherics, and that the transitions between areas work smoothly without calling too much attention to themselves.


Let's look at the roadmap from last month with the updates from this month:

  • Polish the ProHelvetia submission material

  • Polish and revise the combat design

  • Finish the desert music tracks

  • Further blind playtesting and bugfixing

  • Revise the general UI look and feel

  • Implement a main menu, map, and other UI elements (partially done)

  • Create and integrate new sound effects for 90% of the interactions in the game

  • Explore platforming items and mechanics

  • Practise platforming level design

  • Start work on the horizontal slice

I'm quite confident I can get all the UI stuff done in time, so we should be well set for the Pro Helvetia submission!

Until the submission is done, be sure to check our mailing list for weekly updates, and the discord community for fan discussions!

Michał HerdaCommon Lisp Recipes, 2nd Edition

· 84 days ago

Let's talk a little about the second edition of Edi Weitz's Common Lisp Recipes! What would you like to see added or changed in it? What problems have you possibly faced that could be described in a new recipe?

Please let me know via mail, Fediverse, IRC (phoe at Libera Chat), or, if you absolutely have to, Twitter.

McCLIMProgress report #12

· 101 days ago

Dear Community,

A lot of time passed since the last blog entry. I'm sorry for neglecting this. In this post, I'll try to summarize the past two and a half year.

Finances and bounties

Some of you might have noticed that the bounty program has been suspended. The BountySource platform lost our trust around a year ago when they have changed their ToS to include:

If no Solution is accepted within two years after a Bounty is posted, then the Bounty will be withdrawn, and the amount posted for the Bounty will be retained by Bountysource.

They've quickly retracted from that change, but the trust was already lost. Soon after, I've suspended the account and all donations with this platform were suspended. BountySource refunded all our pending bounties.

All paid bounties were summarized in previous posts. Between 2016-08-16 and 2020-06-16 (46 months of donations) we have collected in total $18700. The Bounty Source comission was 10% collected upon withdrawal - all amounts mentioned below are presented for before the comission was claimed.

During that time $3200 was paid to bounty hunters who solved various issues in McCLIM. The bounty program was a limited success - solutions that were contributed were important, however harder problems with bounties were not solved. That said, a few developers who contribute today to McCLIM joined in the meantime and that might be partially thanks to the bounty program.

When the fundraiser was announced, I've declared I would withdraw $600 monthly from the project account. In the meantime I've had a profitable contract and for two years I stopped withdrawing money. During the remaining three years I've withdrawn $15500 ($440/month) from the account.

As of now we don't have funds and there is no official way to donate money to the project (however, this may change in the near future). I hope that this summary is sufficient regarding the fundraiser. If you have further questions, please don't hesitate to contact me, and I'll do my best to answer them.

I'd like to thank all people who donated to the project. Your financial support made it possible for me to work on the project more than I would be able without it. The fact that people care about McCLIM enough to contribute to it money gives me the motivation and faith that working on the codebase is an important effort that benefits the Common Lisp community.


The last update was in 2018-12-31. A lot of changes accumulated in the meantime.

  • Bordered output bug fixes and improvements -- Daniel Kochmański
  • Gadget UX improvements (many of them) -- Jan Moringen
  • Text styles fixes and refactor -- Daniel Kochmański
  • Freetype text renderer improvements -- Elias Mårtenson
  • Extended input stream abstraction rewrite -- Daniel Kochmański
  • Implementation of presentation methods for dialog-views -- admich
  • Encapsulating stream missing methods implementation -- admich
  • indenting-output-stream fixes -- Jan Moringen
  • drawing-tests demo rewrite -- José Ronquillo Rivera
  • Line wrap on the word boundaries -- Daniel Kochmański
  • New margin implementation (extended text formatting) -- Daniel Kochmański
  • Presentation types and presentation translators refactor -- Daniel Kochmański
  • Input completion and accept methods bug fixes and reports -- Howard Shrobe
  • Clipboard implementation (and the selection translators) -- Daniel Kochmański
  • CLIM-Fig demo improvements and bug fixes -- Christoph Keßler
  • The pointer implementation (fix the specification conformance) -- admich
  • Drei kill ring improvements -- Christoph Keßler
  • McCLIM manual improvements -- Jan Moringen
  • Frame icon and pretty name change extensions -- Jan Moringen
  • Cleanups and extensive testing -- Nisar Ahmad
  • pointer-tracking rewrite -- Daniel Kochmański
  • drag-and-drop translators rewrite -- Daniel Kochmański
  • Complete rewrite of the inspector Clouseau -- Jan Moringen
  • Rewrite of the function distribute-event -- Daniel Kochmański and Jan Moringen
  • Adding new tests and organizing them in modules -- Jan Moringen
  • Various fixes to the delayed repaint mechanism -- Jan Moringen
  • CLX backend performance and stability fixes -- Christoph Keßler
  • PS/PDF/Raster backends cleanups and improvements -- Jan Moringen
  • Drei regression fixes and stability improvements -- Nisar Ahmad
  • Geometry module refactor and improvements -- Daniel Kochmański
  • Separating McCLIM code into multiple modules -- Daniel Kochmański and Jan Moringen
  • Frames and frame managers improvements -- Jan Moringen and Daniel Kochmański
  • Frame reinitialization -- Jan Moringen
  • PDF/PS backends functionality improvements -- admich
  • Menu code cleanup -- Jan Moringen
  • Pane geometry and graph formatting fixes -- Nisar Ahmad
  • Numerous CLX cleanups and bug fixes -- Daniel Kochmański and Jan Moringen
  • Render backend stability, performance and functionality fixes -- Jan Moringen
  • Presentation types more strict interpretation -- Daniel Kochmański
  • External Continuous Integration support -- Jan Moringen
  • Continuous Integration support -- Nisar Ahmad
  • Improved macros for recording and table formatting -- Jan Moringen
  • Better option parsing for define-application-frame -- Jan Moringen
  • Separation between the event queue and the stream input buffer -- Daniel Kochmański
  • Examples cleanup -- Jan Moringen
  • Graph formatting cleanup -- Daniel Kochmański
  • Stream panes defined in define-application-frames refactor -- admich
  • Menu bar rewrite (keyboard navigation, click to activate) -- Daniel Kochmański
  • Thread-safe execute-frame-command function -- Daniel Kochmański
  • Mirroring code simplification for clx-derived backends -- Daniel Kochmański
  • Arbitrary native transformations for sheets (i.e. zooming) -- Daniel Kochmański
  • extended-streams event matching improvements -- Jan Moringen
  • Render backend performance improvements -- death
  • drei fixes for various issues -- death
  • drei various cleanups -- Jan Moringen
  • clim-debugger improvements -- Jan Moringen
  • Manual spelling fixes and proofreading -- contrapunctus

This is not an exhaustive list of changes. For more details, please consult the repository history. Many changes I've introduced during this iteration were a subject of a careful (and time-consuming) peer review from Jan Moringen which resulted in a better code quality. Continuous integration provided by Nisar Ahmad definitely made my life simpler. I'd like to thank all contributors for their time and energy spent on improving McCLIM.

Pending work

If you are working on some exciting improvement for McCLIM which is not ready, you may make a "draft" pull request in the McCLIM repository. Currently, there are three such branches:

  • the SLIME-based backend for CLIM by Luke Gorrie

  • the dot-based graph layout extension by Eric Timmons

  • the xrender backend by Daniel Kochmański

Other than that, I've recently implemented the polygon triangulation algorithm that is meant to be used in the xrender backend (but could be reused i.e. for opengl). Currently, I'm refining the new rendering for clx (xrender). After that, I want to introduce a portable double buffering and a new repaint queue. Having these things in place after extensive testing, I want to roll out a new release of McCLIM.

Sincerely yours,
Daniel Kochmański

Nicolas HafnerTesting events - July Kandria Update

· 110 days ago

Another month filled with a lot of different stuff! We have a lot of conferences coming up, there was a bunch to do for marketing, the game has seen a lot of visual and gameplay tweaks, and we've started doing a lot of direct playtesting. Finally, the music has also made a lot of progress and the first few tracks are now done!

GDC, Gamescom, and GIC

Thanks to the very generous support from Prohelvetia we're part of the Swiss Games delegation to GDC, Gamescom, and GIC. GDC is coming up this month, and we have our own virtual booth set up for that. Given that both GDC and Gamescom are virtual this year, I honestly don't really know what to expect from them, it's going to be quite different. At least GIC is in person (Poznan, Poland) so I'm really looking forward to that!

So far we've invested quite a bit of time into looking at journalists to reach out to during GDC, and who knows, perhaps we'll also be contacted by publishers or something during the event. In any case, it's going to be an exciting week, for sure.

Gamescom/Devcom are coming up in August, right before the submission deadline for the Prohelvetia grant, so that's going to be a tight squeeze, too. September is gonna be a calmer month, as we've settled for a two weeks holiday for the team during that month. Then in October it's going to be GIC for a week.


Also thanks to Prohelvetia we now have direct mentoring from Chris Zukowski with a monthly meeting for the next six months. His first advice was to focus a lot more on top of the funnel marketing (like imgur, reddit, festivals, influencers), and cut down on all the middle stuff we've been doing (like discord, mailing list, blogs, streams).

I actually quite like doing the weekly and monthly updates though, so I'm going to keep doing those. The Sunday streams have also proven quite productive for me, so I'll use them for that purpose too, rather than for any marketing intent. I am going to cut down drastically on Twitter though, as that does not seem to really bring us much of anything at all, and I'm going to stay away from Discord more in general (not just the Kandria one.).

After some brief experiments with imgur (and once even making it into most viral) I haven't returned to that yet though, as I've found it to be quite exhausting to figure out what to even post and how to post it.

We'll definitely have to try reaching out to influencers and journalists, but we're going to hold off on that until the september demo update is done, as a more polished demo should help a lot to make us look more presentable and respectable. We should also try out Reddit, but we haven't done the necessary research yet into how exactly to post on there without getting downvoted into oblivion.

The second advice Chris had for us was to do more....


We've started inviting people to do blind playtesting. The blind here meaning that they never played the game before, which gives us quite valuable insight into parts of the game that are confusing or annoying. We've done four sessions so far, and even with them being carried out over Discord, the feedback has been very useful.

I've also been inviting people for local playtesting, as being able to observe people in person is a lot better than doing it over the net. We haven't done any of that yet, but there's several appointments scheduled already. If you're near Zürich and would be up for a playtest session, please book a date!

And if you, like most, aren't close to Zürich, but would still like to help us out with testing, let me know anyway and we can arrange something over the net!


We finally finished a tutorial area for the game, giving it a proper starting point, and introducing people to the controls. It doesn't explain all of them in detail though, as I think we should instead keep the more intricate controls to challenges throughout the game, rather than trying to teach everything at once.

Designing the levels to teach the various control parts is going to be challenging, but I think ultimately it is going to be worth it, especially as it allows us to keep the tutorial in the beginning very short.

The only actual tutorial part still missing is a combat primer, for which we haven't worked out a good way of teaching it yet. I'm sure we'll find a way, though.


I took a holiday for part of this month, though otherwise it's been full steam ahead on the marketing research. I've added more reference games and potential contacts to our press & influencer document; while doing this I've taken into account the advice we got from Chris Zukowski, about not looking too closely at games with distinct differences to Kandria (e.g. Celeste has no combat; Dead Cells is a roguelike). I've also done more research on Steam short descriptions, and worked with Nick to redraft ours. It needs a few more edits, but it's nearly there.

I haven't totally forgotten the game though! With the new tutorial prologue in place, I added dialogue. This is now your first meeting with Catherine, after she reactivates you deep underground; but I've deliberately kept things short and sweet, as she guides you back up to the surface. The player has enough to think about at this stage without getting overwhelmed with dialogue; only once the tutorial segues into the settlement introduction from before, does the dialogue really begin.


Mikel's been very busy and completed 6 different versions of the region 1 track:

Which the game can use to do vertical mixing:


Let's look at the roadmap from last month with the updates from this month:

  • Build and add the tutorial sequence to the beginning of the game

  • Finish the region 1 music tracks

  • Add a fishing minigame

  • Improve the UI for the game and editor

  • Implement several editor improvements

  • Compile data on journalists, influencers, and communities

  • Implement a UI animation system

  • Implement a cutscene system

  • Polish the ProHelvetia submission material (partially done)

  • Polish and revise the combat design (partially done)

  • Implement a main menu, map, and other UI elements

  • Reach out to journalists, streamers, and other communities

  • Explore platforming items and mechanics

  • Practise platforming level design

  • Start work on the horizontal slice

The first three are scheduled to be done by September 1st, and so far it looks quite doable. The events are going to jumble things up a bit, but I hope that we still have enough time scheduled around to get it all done in time.

Until then be sure to check our mailing list for weekly updates, and the discord community for fan discussions!

Quicklisp newsJune 2021 Quicklisp dist update now available

· 112 days ago

 New projects

  • cl-megolm — A copy of the python functionality provided as bindings for Olm. — MIT
  • cl-openapi-parser — OpenAPI 3.0.1 and 3.1.0 parser/validator — MIT
  • cl-opencl-utils — OpenCL utility library built on cl-opencl — GPLv3
  • cl-sse — Use sse-server + a web service to serve SSE events to a browser. — MIT
  • trivial-ed-functions — A simple compatibility layer for *ed-functions* — MIT
  • trivial-inspector-hook — A simple compatibility layer CDR6 — MIT
  • webapi — CLOS-based wrapper builder for Web APIs — BSD 2-Clause
  • whirlog — a minimal versioned log structured relational DB — MIT

Updated projects: also-alsa, april, atomics, bdef, binding-arrows, bp, chirp, cl+ssl, cl-ana, cl-collider, cl-conllu, cl-cxx-jit, cl-data-structures, cl-environments, cl-form-types, cl-gamepad, cl-gserver, cl-heredoc, cl-incognia, cl-ipfs-api2, cl-kraken, cl-maxminddb, cl-mixed, cl-mock, cl-murmurhash, cl-naive-store, cl-ntp-client, cl-opencl, cl-patterns, cl-schedule, cl-smt-lib, cl-string-generator, cl-torrents, cl-utils, cl-webkit, clack-pretend, closer-mop, cluffer, clunit2, clx, cmd, common-lisp-jupyter, conium, consfigurator, core-reader, croatoan, defmain, deploy, dexador, djula, doc, easy-routes, eclector, fiveam-asdf, fresnel, functional-trees, gendl, generic-cl, gute, harmony, herodotus, hunchentoot-multi-acceptor, hyperluminal-mem, iolib, lack, lichat-protocol, lichat-tcp-client, lispqr, markup, mcclim, md5, mito, mnas-package, mnas-string, modularize-interfaces, multiposter, neural-classifier, numerical-utilities, nyxt, origin, osmpbf, overlord, plot, plump, portal, postmodern, py4cl2, qlot, quilc, quri, qvm, re, replic, sc-extensions, sel, serapeum, shasht, shop3, sly, smart-buffer, special-functions, spinneret, st-json, static-dispatch, static-vectors, stumpwm, sxql, tailrec, tfeb-lisp-hax, tooter, trivia, trivial-with-current-source-form, trucler, vellum, vk, wasm-encoder, woo, zippy.

Removed projects: with-c-syntax.

To get this update, use (ql:update-dist "quicklisp"). Enjoy!

Nicolas HafnerUpdates Galore - June Kandria Update

· 137 days ago

There's a lot of different news to talk about this month, so strap in!

The New Trailer

The most important thing to come out of this month is the new trailer! Check it out if you haven't yet:

I'm overall really happy with how it came together, and we all had a part in the end result. I'd also like to give a special commendation to Elissa Park who did the amazing voice over for the trailer. It was a pleasure to work together!

It's also been great to finally get some custom music by Mikel into an official part of the game. He's also been working on the first music tracks that'll be in the game, and I've been working on a music system to support horizontal mixing with the tracks. I'm very excited to get all that together into the game and see how it all feels! I hope that by next month's update we'll have a short preview of that for you.

0.1.1 Release

Meanwhile we also pushed out an update to the vertical slice release that makes use of the new linear quest system we put together. It should overall also be a lot more stable and includes many fixes for issues people reported to us. Thanks!

As always, if you want to have a look at the demo yourself, you can do so free of charge.

I think this will be the last patch we put out until September. I can't afford to backport fixes even if more bug reports come in, as the overhead of managing that is just too high. I can't just push out new versions that follow internal development either, as those are frequently in flight and have more regressions that we typically stamp out over time, but would in the meantime provide a more buggy experience. started working on fishing just recently!

Dev Streams

I'm heavily considering doing regular weekly development streams, both to see if we can attract some more interest for the project, and to be more open about the process in general. I feel like we're already very open about everything with our weekly updates, but having an immediate insight into how the game is made is another thing entirely. I think it would be really cool to show that side of development off more often!

In order to coordinate what time would suit the most people, please fill out this Doodle form. The exact dates don't matter, just watch for the day of the week and the time. Don't worry about the name it asks for either, it won't be public!

I'll probably close the poll in a weeks, so make sure to submit an answer soon if you're interested. Streams will happen both on and, with both being reachable through the official stream page at . See you there!

Palestinian Aid Bundle

Some good folks have put together a bundle on gathering money for Palestinian aid. I'm very happy to say that our game, Eternia: Pet Whisperer is a part of this bundle!

If you want to support this cause and get a huge collection of amazing games in the process, head on over to!


This month I had a varied mix of tasks: working on the script for the new trailer; updating the quests in the vertical slice demo to work closer to our original vision; researching press and influencer contacts as we plan more of Kandria's marketing.

The trailer came out great, and I'm really happy with the voice acting that Nick produced with Elissa Park. It was a great idea Nick had to use the character of Fi as the narrator here (originally we were going to use Catherine) - her serious outlook, and reflection on the events of the story, was just what we needed to fit the epic music from Mikel, and the epic gameplay and exploration that Nick captured on screen. The whole thing just screams epic.

The quests were vastly improved too. The first quest now uses Nick's new sequencing system, so that triggers fire automatically (and more robustly) when the player arrives at the correct location, and when combat encounters are completed. The logic is also much quicker to write, so linear quests will be much faster to produce in the future. The mushroom quest also had a big refactor; now you can organically collect mushrooms out in the world, rather than going to specific enabled points. You can even sell what you find to the trader, including those poisonous black knights. It really makes the world feel more interactive. There's been general tweaks to the other quests from playtesting, and I'll continue to refine them from my own playing and players' feedback up until the Pro Helvetia submission later in the year. I'm also planning to add a couple more sidequest diversions based on the new fishing (!) minigame being added at the moment; we think a combat-focused sidequest will work well too.

Finally on the marketing side, it's been rewarding to collect tons of potential press and influencer contacts we could approach in the future. I've basically been taking games that are strong influences and have similarities to Kandria - from hugely popular games like Celeste and Dead Cells, to lesser known ones like Kunai and Armed with Wings - then cataloguing key journalists and influencers who've streamed, made videos, or written about them. This will hopefully highlight some of the right people we can contact to help spread the word about the game.


Let's look at the roadmap from last month with the updates from this month:

  • Make the combat more flashy

  • Finish a new trailer

  • Revise the quest system's handling of linear quest lines

  • Design and outline the factions for the rest of the game

  • Develop the soundscape for Kandria and start working on the tracks for region 1

  • Add a music system that can do layering and timed transitions

  • Build and add the tutorial sequence to the beginning of the game

  • Finish the region 1 music tracks

  • Reach out to journalists, streamers, and other communities

  • Polish the ProHelvetia submission material

  • Polish and revise the combat design

  • Explore platforming items and mechanics

  • Practise platforming level design

  • Start work on the horizontal slice

As always there's some smaller tasks that aren't in the overall roadmap. We seem to be doing pretty well keeping on track with what needs done, which is really good! It's all too easy to misjudge the time required to complete things, especially in games.

In any case, time is flying fast, and there's a lot to do. In the meantime be sure to check our mailing list for weekly updates, and the discord community for fan discussions!

Eric TimmonsASDF 3.3.5 Release Candidate

· 140 days ago

ASDF has been tagged. This is a release candidate for 3.3.5. As the announcement says, please give it a spin on your setup and report any regressions. Bugs can be reported to the Gitlab issue tracker (preferred) or to the asdf-devel mailing list.


The full(ish) Changelog can be found here.

In addition to assorted bug fixes, there are several new features. Both user facing:

  • Support for package local nicknames in uiop:define-package.
  • SBCL should now be able to find function definitions nested in the with-upgradability macro.
  • package-inferred-system source files can use extensions other than .lisp.

And developer facing:

  • Building out a fairly extensive CI pipeline.


This is planned to be the last release in the 3.3 series. We are excited to get this out the door because we already have several focal points for the 3.4 series in mind, including:

  • Support for more expressive version strings and version constraints. issue draft MR.
  • A new package defining form that is explicitly designed to better tie in with package-inferred-system. issue draft MR.

Please join in the conversation if any of these features excite you, you have features you'd like to see added, or you have bugs that need to be squashed.

Michał HerdaCurrent Common Lisp IRC situation

· 142 days ago

Because of the upheaval at Freenode, I've migrated to Libera Chat along with a bunch of other Lisp programmers. We have used that as a chance to make some small changes to the channel structure:

  • #commonlisp is the on-topic Common Lisp channel (formerly #lisp),
  • #lisp is the somewhat on-topic discussion about all Lisp dialects (formerly ##lisp),
  • the rest of the channel names should work the same.

The first two lines of the above were mentioned because #lisp on Freenode used to have a non-trivial volume of people asking questions about Scheme or Emacs Lisp due to the too-generic channel name. Naming the Common Lisp channel #commonlisp resolves this issue, at the cost of sacrificing a lucrative and attractive five-character channel name.

Quicklisp newsMay 2021 Quicklisp dist update now available

· 143 days ago

 New projects: 

  • adopt-subcommands — Extend the Adopt command line processing library to handle nested subcommands. — MIT
  • cl-cerf — Lisp wrapper to libcerf — Public Domain
  • cl-cxx-jit — Common Lisp Cxx Interoperation — MIT
  • cl-form-types — Library for determining types of Common Lisp forms. — MIT
  • cl-incognia — Incognia API Common Lisp Client — MIT
  • cl-info — A helper to an answer a question about OS, Lisp and Everything. — BSD
  • cl-mimeparse — Library for parsing MIME types, in the spirit of, with a Common Lisp flavor. — MIT
  • cl-opencl — CFFI for OpenCL and Lisp wrapper API — Public Domain
  • cl-schedule — cl-schedule is a cron-like scheduling library in common-lisp. It subsumes and replaces traditional cron managers thanks to richer expressiveness of Lisp. — MIT
  • cl-vorbis — Bindings to stb_vorbis, a simple and free OGG/Vorbis decoding library — zlib
  • claw-olm — Thin wrapper over OLM — MIT
  • context-lite — A CLOS extension to support specializing methods on special/dynamic variables. — MIT
  • defmain — A wrapper around net.didierverna.clon which makes command line arguments parsing easier. — BSD
  • defrest — defrest: expose functions as REST webservices for ajax or other stuff — BSD
  • doc — Documentation generator, based on MGL-PAX. Allows to put documentation inside lisp files and cross-reference between different entities. — MIT
  • ec2-price-finder — Quickly find the cheapest EC2 instance that you need across regions — BSD-3-Clause
  • file-notify — Access to file change and access notification. — zlib
  • fresnel — Bidirectional translation with lenses — MIT
  • log4cl-extras — A bunch of addons to LOG4CL: JSON appender, context fields, cross-finger appender, etc. — BSD
  • mnas-package — Система @b(mnas-package) предназначена для подготовки документации, извлекаемой из asdf-систем. @begin(section) @title(Мотивация) Система @b(Codex) является достаточно удобной для выполнения документирования систем, написанных с использованием @b(Common Lisp). Она позволяет получить на выходе документацию приемлемого вида. К недостатку сустемы @b(Codex) можно отнести то, что формирование шаблона документации не выполняется автоматически. Указание на включение разделов документации, относящихся к отдельным сущностям к которым можно отнести: @begin(list) @item(системы;) @item(пакеты;) @item(классы;) @item(функции, setf-функции;) @item(обобщенные функции,методы, setf-методы;) @item(макросы;) @item(и т.д., и т.п.) @end(list) приходится формировать вручную. Этот проект пытается устранить данный недостаток системы @b(Codex) за счет определения функций и методов позволяющих: @begin(list) @item(формировать код, предназначенный для передачи в систему @b(Codex);) @item(формировать представление отдельных частей системы в виде графов.) @end(list) @end(section) — GNU GENERAL PUBLIC LICENSE Version 3, 29 June 2007 or later
  • mnas-string — Система @b(mnas-string) предназначена для: @begin(list) @item(парсинга вещественного числа;) @item(разделения строки на подстроки;) @item(замены всех вхождений подстроки в строке;) @item(замены множественного вхождения паттерна единичным;) @item(подготовки строки в качестве аргумента для like запроса SQL;) @item(обрамления строки префиксом и постфиксом;) @item(вывода представления даты и времени в поток или строку;) @item(траслитерации строки.) @end(list) — GNU GENERAL PUBLIC LICENSE Version 3, 29 June 2007 or later
  • osmpbf — Library to read OpenStreetMap PBF-encoded files. — MIT
  • plot — Plots for Common Lisp — MS-PL
  • scheduler — Extensible task scheduler. — BSD-2-Clause
  • speechless — A dialogue system language implementation. — zlib
  • stumpwm-sndioctl — Interface to OpenBSD's sndioctl for StumpWM. — ISC
  • vellum — Data Frames for Common Lisp — BSD simplified
  • vellum-clim — Simplistic vellum data frames viewer made with mcclim. — BSD simplified
  • vellum-csv — CSV support for Vellum Data Frames — BSD simplified
  • vellum-postmodern — Postgres support for Vellum Data Frames (via postmodern). — BSD simplified
  • vk — Common Lisp bindings for the Vulkan API. — MIT
  • wasm-encoder — Library for serializing WebAssembly modules to binary .wasm files — MIT

Updated projects: adopt, agutil, also-alsa, anypool, april, architecture.builder-protocol, async-process, audio-tag, bdef, bnf, burgled-batteries.syntax, caveman, chirp, cl+ssl, cl-ana, cl-argparse, cl-async, cl-collider, cl-covid19, cl-cuda, cl-data-frame, cl-data-structures, cl-environments, cl-forms, cl-gamepad, cl-glfw3, cl-gserver, cl-kraken, cl-liballegro, cl-liballegro-nuklear, cl-markless, cl-mixed, cl-naive-store, cl-num-utils, cl-patterns, cl-pdf, cl-prevalence, cl-rfc4251, cl-sendgrid, cl-slice, cl-smt-lib, cl-ssh-keys, cl-steamworks, cl-str, cl-tiled, cl-typesetting, cl-utils, cl-webkit, clack, clack-pretend, clath, clavier, clog, closer-mop, cmd, coleslaw, common-lisp-jupyter, configuration.options, consfigurator, croatoan, cytoscape-clj, damn-fast-priority-queue, data-frame, dataloader, defconfig, definitions, deploy, dfio, diff-match-patch, dissect, djula, dns-client, doplus, dufy, duologue, easy-routes, eclector, erudite, file-attributes, flare, fmt, functional-trees, gendl, generic-cl, golden-utils, gute, harmony, herodotus, hu.dwim.presentation, hunchenissr, hunchensocket, hunchentoot-errors, iterate, kekule-clj, lack, language-codes, lichat-protocol, lisp-stat, literate-lisp, magicffi, maiden, math, mcclim, messagebox, mnas-graph, mnas-hash-table, multiposter, mutility, named-readtables, nibbles, nodgui, numcl, numerical-utilities, nyaml, nyxt, overlord, parseq, pathname-utils, plump-sexp, plump-tex, portable-threads, postmodern, pzmq, qlot, qt-libs, rpcq, sb-cga, sc-extensions, screamer, sel, serapeum, shadow, shop3, specialized-function, spinneret, split-sequence, static-dispatch, static-vectors, stumpwm, sxql, ten, tfeb-lisp-hax, trivial-indent, trivial-timer, trivial-with-current-source-form, trucler, uax-15, vgplot, wild-package-inferred-system, with-c-syntax.

To get this update, use (ql:update-dist "quicklisp"). Enjoy!

Pavel Korolev:claw honing - Beta milestone and alien-works

· 145 days ago

Long time no see my C++ autowrapping rants. But several bindings later, :claw has reached the stage where it is ready to leave a garage and see the outside world. Since my last post, some approaches were revised, though the autowrapping process is still not fully cemented yet. I wouldn't expect :claw to be out of beta for at least a year. That doesn't mean it is unusable, but rather I cannot guarantee a stable interface and a trivial procedure for setting it up.

In other big news, :alien-works system got all required foreign libraries wrapped and integrated, including some complex and peculiar C++ ones (Skia 👀). Next step is to write a game, based on :alien-works framework, to see how much lispification of autowrapped systems is possible without loosing any performance and what is required for a solid game delivery.

TurtleWareA small hack for the class redefinition

· 151 days ago

Consider the following class:

(defclass boring-class ()
  ((a :initarg :a :initform 'a :accessor a)
   (b :initarg :b :initform 'b :accessor b)
   (c :initarg :c :initform 'c :accessor c))
  (:default-initargs :c 'the-c))

(defmethod print-object ((instance boring-class) stream)
  (print-unreadable-object (instance stream :type nil :identity nil)
    (format stream "~a, ~a, ~a" (a instance) (b instance) (c instance))))

Now create an instance of it:

(defvar *boring-instance* (make-instance 'boring-class :b 'the-b))
(print *boring-instance*) ;;; #<A, THE-B, THE-C>

Redefining the class with different initial values has no effect on the instance local slots because they are not changed:

(defclass boring-class ()
  ((a :initarg :a :initform 'the-a :accessor a)
   (b :initarg :b :initform 'b :accessor b)
   (c :initarg :c :initform 'c :accessor c))
  (:default-initargs :c 'the-c))
(print *boring-instance*) ;;; #<A, THE-B, THE-C>

However if we define a new slot (casually - change its name) the CLOS machinery will update the instance:

(defclass boring-class ()
  ((X :initarg :a :initform 'new-a :accessor a)
   (Y :initarg :b :initform 'b :accessor b)
   (Z :initarg :c :initform 'new-c :accessor c))
  (:default-initargs :b 'new-b))
(print *boring-instance*) ;;; #<NEW-A, NEW-B, NEW-C>

In other words to trigger the slot update after each class redefinition we have to always provide a different name for the slot.

(defclass boring-class ()
  ((#.(gensym) :initarg :a :initform (random 42) :accessor a)
   (#.(gensym) :initarg :b :initform (random 42) :accessor b)
   (#.(gensym) :initarg :c :initform (random 42) :accessor c)))

(print *boring-instance*) ;;; #<15, 13, 18>
;; recompile defclass
(print *boring-instance*) ;;; #<3, 4, 38>
;; recompile defclass
(print *boring-instance*) ;;; #<32, 12, 10>

This is not the cleverest trick because we may have a better control over slots for example by defining the method for the function reinitialize-instance however I've found the use of gensyms surprising and funny. Cheers!

P.S. As pointed out by Michał Herda, using uninterned symbols will give us the same behavior and will preserve the symbol name of the slot name.

(defclass boring-class ()
  ((#:a :initarg :a :initform (random 42) :accessor a)
   (#:b :initarg :b :initform (random 42) :accessor b)
   (#:c :initarg :c :initform (random 42) :accessor c)))

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Last updated: 2021-10-21 01:47