Distributed concurrency in Factor

Chris Double writes about distributed concurrency in Factor. This is built on top of his existing Erlang-like concurrency library, and uses serialization to pass messages between nodes. Cool stuff.

Scheme-based real time music programming environment for OS X

Impromptu looks interesting. I just wonder why it wasn't implemented in Scheme, since they already use it for scripting.

Object serialization

Long-time Factor contributor Chris Double has dusted off an incomplete serialization library and polished it up. You can find the code in contrib/serialize/. Now Factor can serialize objects to binary and back again, preserving object identity, shared structure and circularity. He mentioned he will be using this to extend the concurrency library to support distributed message passing. That is just too cool.

New stack-based language

Robbert van Dalen is working on a new stack-based language called The whole enchilada.

Generic editor hook

For a while now Factor had a jedit word in the core which would jump to a word definition in a running jEdit instance. Well since then, emacs and vim integration has appeared in contrib/, so I thought it is time to make this hook generic. Now there is a new edit word which calls a quotation stored in the edit-hook global variable with a file name and line number on the stack. The jEdit code has been moved to contrib/jedit/. Loading either the jedit, vim or emacs module sets the edit hook. There is also a new feature: the :edit word starts your editor at the location of the most recent parser error.

New commands in the UI listener

Soon, there will be a CLIM-like unified command framework and keyboard help. For now, I'll just have to write a blog entry about the new keyboard commands:

Command	Shortcut
Stack effect of entered quotation	C+i
Single-step entered quotation	C+w
Completions for word at caret (used vocabs)	TAB
Completions for word at caret (all vocabs)	A+a
Reload word at caret	A+r
jEdit word at caret	A+j
See word at caret	A+s
See word at caret	A+s
Use first vocab containing word name at caret	A+u

The single stepper has some shortcuts too:

Step	s
Step in	i
Step out	o
Continue	a
Step back	b

"Step back" feature in single stepper

The new graphical single stepper in Factor 0.84 can now travel back in time and "step back" through a quotation. This only restores the stack contents, it does not undo side effects. Still, even though the time travel is far from perfect, it is still useful, especially for beginners learning the language and figuring out how stuff works. They can step over some words, then rewind and step in to look at things in more detail.