Posts Tagged ‘scheme’

Andy Wingo: recent developments in Guile

2010-04-19

I watched a talk by Andy Wingo recently: recent developments in Guile. GNU Guile is a Scheme implementation, and a library providing an extension language for applications. Guile is actively developed, and promises some exciting stuff in upcoming releases, which is why I took these notes and publish them here–read on.

Andy starts by noting that Guile is different things to different people:

  • A GNU language, with bindings for many components of the GNU system and under LGPL 3.
  • A Scheme implementation, supporting R5RS and part of R6RS, plus other goodies: modules (not the R6RS ones), hygienic macros, the CLOS-like object system Goops with transparent integration with GLib’s gobject, Posix interface, and Unicode support.
  • An extension language for applications, like the Gimp.
  • A part of the GNU system (that we are making, even if we don’t know yet how it will look like).

Andy sees Guile’s perception among developers as its main challenge currently. It’s seen as being slow, although it’s generally faster than Python. But there are also opportunities for its perception: its multilingual vision and support–its next release will support ECMAScript besides Scheme, and Emacs Lisp is coming–, and the GNU brand.

Some technical notes

It uses the Boehm-Weiser garbage collector now, which is fast and reliable.

There are ten committers and monthly releases. This is after the project emerged from a long drought in 2000-2007.

Guile has a VM, and a native compiler is coming. Also: JavaScript support, ELisp coming!

It has really good Emacs integration now with Geiser.

There was also a small remark about licensing. Readline and Guile are not quite license-compatible, which makes using the REPL a pain. This sparked a longish discussion–kinda what you expect from a GNU developers meeting :-)

Spreading the Emacs nature

And now, the meat of the talk: spreading the Emacs nature, to emacsify the GNU system. Yes, that sounds like it!

The upcoming Guile 2.0 (or maybe 2.1?) will have full ELisp support, at the moment about equally fast than Emacs’ own, but it will be much faster. It will also have native compilation for even more performance.

Besides performance, it will have much more to offer:

  • native threads,
  • a clear FFI,
  • modules,
  • other languages, as described above,
  • the Goops object system,
  • lots of library bindings – Emacs-Gnome integration would easily be possible, for instance.

Andy’s plan is to replace Emacs’ Lisp engine with Guile. The rest stays unchanged, existing ELisp code will run as-is. Then no form of coercion should be necessary to get people to start writing their Emacs code in Guile languages. The timeframe is 18-30 months from now–looks like a developer release is not too far off!

SICP in Emacs

2009-12-04

Most people reading this will know that Structure and Interpretation of Computer Programs (SICP) by Abelson and Sussman is one of the most well known and recommended books when it comes to core Computer Science, algorithms, and functional programming. Suffice it to say, if you want to explore these areas and enhance your programming on a level beyond knowing the latest framework, check out this book. It’s freely available online, as well as recordings of lectures the authors gave.

Now, in case that’s not nerdy enough for you, I found a version in texinfo yesterday. Complete with all graphics converted to ASCII art. Yes, kinda scary, but it rocks: have your Emacs display an info buffer with the book and a Scheme or CL REPL to play with the book’s code and work on the exercises. Just move around the book and evaluate the code snippets there. Neat!

I guess that means I have to resume my project of working through the exercises. I’m not even sure where my first couple solutions are…


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