3 Aug
2014
3 Aug
'14
2:48 a.m.
From: "A. P. Garcia"
<a.phillip.garcia(a)gmail.com>
Being so small, I expected the editor to lack a
scripting language.
Well, there is a companion 'compiler' which converts extension source into
the intermediate form (byte-code) which is interpreted by the editor. But
it's even smaller (67KB!) and as fast as the editor itself.
I was pleasantly surprised that it does have one, and
that it's a c
derivative ... "Extensible and modifiable" doesn't always mean the same
thing to everyone, and well, you're a kernel hacker.
Take a quick look at a source file, e.g. one of mine:
http://ana-3.lcs.mit.edu/~jnc/tech/cmd.e
and you'll see i) what it's like (except for a few new editing-specific
keywords, such as 'on <key>' in function definitions, it's pretty
much C),
and ii) it will give you a sense of the kind of things one writes in it, and
how easy it is to do so.
The underlying run-time basically just provides buffer, display, etc
primitives, and pretty much all the actual editor commands are written in the
'extension' languge, even simple things like 'forward character' (^F),
etc.
The complete manual is available online, the run-time system is described
here:
http://www.lugaru.com/man/Primitives.and.EEL.Subroutines.html
Epsilon comes (as of a few versions back, I haven't bothered to upgrade) with
about 22K lines of source, which is the bulk of the actual editor; that turns
into about 190KB of intermediate code.
Noel