programming musings

The latest conjure48 version at my repository is able to build s42, and run the test suites—doc generation is almost there too.

If you have the s42 source tree, you can try it with the following incantations [1]:

  $ ln -s conjure/examples/s42/build.scm .
  $ ln -s conjure/examples/s42/build.exec .
  $ scheme48
  > ,exec ,load "build.exec"
  > (build-system "s42" "test")

That will run the testsuite. Other goals that can be used instead of ‘test’ are ‘runners’, ‘s42.image’ or ‘doc’. If you take a look at the build script and find it ugly, please keep in mind that this is still alpha code, and that s42 is a rather complex system when it comes to building. This simpler build file for a test C project is closer to what we envision. From here, we’ll be polishing the syntax and interfaces to attain our DSL-for-non-schemers goal.

If you are in Vienna tomorrow, don’t miss rotty’s talk on scheme, s48 and s42 for Debienna, where Conjure will make its world wide debut :-).

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[1] There are some tricky issues that you may stumble upon to get there. Please, do not hesitate to contact us at #conjure in Freenode.

Tags: conjure, make, scheme

Conjure48′s development is evolving at a slow but steady pace. We are already able, for instance, to compile C/C++ code, including dynamic libraries, both in GNU/Linux and Mac OS X. And a build script for s42 (getting rid of Scons in the process) is on the way.

Our latest addition is rotty’s logging package, which is not Conjure-specific and very interesting, in and by itself. Actually, this new logging facility is part of Spells, thus being portable to several Scheme implementations. Please, follow the link above for rotty’s detailed report.

As an aside, and just in case you’re wondering how on earth Spells, s42 and Conjure relate to each other, here’s a quick summary of the stuff we’re trying to release:

• Spells is a portable set of Scheme libraries, compatible with several Scheme implementations: Scheme48, PLT Scheme, Guile and Gauche are our current targets. Spells includes lots of utilities, from regular expressions to an implementation of T’s object system, a document generation system or a unit testing framework. Of course, we’re not generating all that stuff from scratch, but frequently adapting existing libraries to Spells’ portability framework. You can get a feeling of Spells breadth in this draft API documentation.
• s42 is a collection of scheme48 libraries and extensions. To boot, it includes all Spells modules, and then much more (for instance, spenet, and implementation of rotty’s network API proposal).
• s42 serves as the basis to s48-worlds, a framework aimed at supporting distributed s48 package repositories (a little bit like PLT’s PLaneT).
• Conjure uses Spells for portability, and is the build system for s42. In other Schemes, it will run as a standalone make replacement, without any dependency on s42.

As you can imagine, there’s lots of room for new developers by here, whatever your Scheme of choice is. If you want to join the fun, drop any of us a mail, or look for us at #conjure or #scheme in Freenode.

Tags: conjure, make, s42, scheme

My current scheming is centered around Conjure, a make(1) replacement written in Scheme.

If you are familiar with Scons, a good approximation is to think about Conjure as Scons, but using Scheme instead of Python. The key point in these systems is that the language is not just an implementation detail (as, say, C is in make), but soars up to surface in that build scripts are actually Scheme (or Python) programs.

I don’t think i need to go into the details of why having at your disposal a full-fledged high-level language has advantages. But of course, more power implies more risks, and end users my be confused with, or not willing to learn, your favourite programming language. This, in my opinion, is a problem much easily surmountable in Scheme than Python (and that’s one of the reasons i keep working on Conjure, Scons notwithstanding). How so? Syntactic abstraction, of course. Besides having a far simpler syntax, Scheme (and Lisp in general) is the perfect vehicle to implementing domain-specific languages (see, for instance this nice article by V.S. Lugosky).

Thus, one of the goals of Conjure is to provide a declarative DSL tailored to defining software construction tasks and their interrelationships, usable as such even without any knowledge of Scheme. But then, DSL or not, a Conjure build file is still a Scheme program, and power users can extend and twist the system as much as they want.

The initial draft of the Conjure User’s Manual has an introductory section where i indulge in a boring discussion of these issues, if you’re so perversely inclined. The rest of the manual, by the way, is hopelessly inaccurate and out of sync with the current implementation, which you can browse in my darcs repository.

As you will see, nowadays Conjure is embedded in a wider plan for world domination which includes Spells, s48-worlds and s42. Those projects have been impulsed by my talented and indefatigable friend and conniver Rotty, who finally assimilated me into the s48 underground.

The Conjure homepage provides more details and links. Please, don’t be put off if you’re not a scheme48 aficionado: eventually, Conjure will run on as many Scheme implementations as possible. This is why it is based on Spells (which had its beginnings as a Conjure library, but thanks to Rotty has grown up into a project (very) worth in and by itself), a portability framework. Think of the current conjure48 as a proof-of-concept implementation that will settle the basis for the portable Conjure.

Tags: conjure, lisp, make, scheme