deuce-terminal is a terminal-based interface to the Deuce editor
written in Dylan.
It provides a minimal UI toolkit for working with the terminal which is layered on top of libtickit and libtermkey. It then provides an implementation of the Deuce interfaces required to hook it up to this new user interface library.
Deuce is a descendant of ZWEI, which was itself a descendant of early emacs and was written by Scott McKay at Harlequin.
Scott wrote a bit about what makes Deuce different in a newsgroup posting:
gnuemacs is quite different from the Eine/Zwei family of
editors, in that it uses the "bigline" structure to model the
contents of its buffers. Hemlock and the LW editor also
use this representation. Buffer pointers (BPs) are then simply
integers that point into the bigline. This can be a very space-
efficient structure, but the downside is that it is very hard to
have any sort of polymorphic "line" object. This makes it
much tougher to do things like graphics; a friend from Lucid
told me that Jamie Zawinski, a formidable hacker, spent about
a year a year wrestling with gnuemacs before he could make
it general enough to do the sorts of things he got Xemacs to do.
Zwei models buffers as linked lists of line objects, and BPs
are a pair {line,index}. This makes it easier to do some
clever stuff in Zwei, but IIRC lines in Zwei are structures,
not classes, so it turned out that we had to wrestle quite a
bit with Zwei to get display of multiple fonts and graphics
to work (on the order of many weeks).
The editor for FunO's Dylan product -- Deuce -- is the
next generation of Zwei in many ways. It has first class
polymorphic lines, first class BPs, and introduces the idea
first class "source containers" and "source sections". A
buffer is then dynamically composed of "section nodes".
This extra generality costs in space (it takes about 2 bytes of
storage for every byte in a source file, whereas gnuemacs
and the LW editor takes about 1 byte), and it costs a little
in performance, but in return it's much easier to build some
cool features:
- Multiple fonts and colors fall right out (it took me about
1 day to get this working, and most of the work for fonts
was because FunO Dylan doesn't have built-in support for
"rich characters", so I had to roll my own).
- Graphics display falls right out (e.g., the display of a buffer
can show lines that separate sections, and there is a column
of icons that show where breakpoints are set, where there
are compiler warnings, etc. Doing both these things took
less than 1 day, but a comparable feature in Zwei took a
week. I wonder how long it took to do the icons in Lucid's
C/C++ environment, whose name I can't recall.)
- "Composite buffers" (buffers built by generating functions
such as "callers of 'foo'" or "subclasses of 'window') fall right
out of this design, and again, it took less than a day to do this.
It took a very talented hacker more than a month to build a
comparable (but non-extensible) version in Zwei for an in-house
VC system, and it never really worked right.
Of course, the Deuce design was driven by knowing about the
sorts of things that gnuemacs and Zwei didn't get right (*). It's so
much easier to stand on other people shoulders...
(*) By "didn't get right" I really mean that gnuemacs and Zwei had
design goals different from Deuce, and in fact, they both had initial
design goals that were different from where they ended up.
Be sure that you have cloned this repository recursively or have
initialized and updated the submodules. (Without doing this, the
tickit binding library won't be found.)
The sources for Deuce itself are part of the standard Open Dylan distribution.
For now, customized versions of libtermkey and libtickit have
been included within deuce-terminal, so you won't have to install
these on your own.
Once that is done, building deuce-terminal should be as easy
as running make. The resulting binary will be _build/bin/dt.