I've been thinking about the minimal feature set a beginner-friendly
ruby development/learning environment should have. I feel the
following are essential:

1. An editor pane

2. A drracket-style repl, that can reset itself and reload all the
definitions from the editor pane

3. The ability to run the program from within the IDE

4. Built-in docs (possibly via launching a browser window, though I
note that drracket took a definite hit in how friendly it felt when it
went that route)

* How close can we come to this with the current tools out there?

1. The editor pane is of course what every IDE is built around

2a. It's not too hard to embed a repl in a text pane. I experimented
with it a bit a couple of years ago
[https://github.com/martindemello/guirb/] and jruby has jirb_swing.

2b. Given that an IRB session is accessible as an object, it shouldn't
be too hard to have it reread definitions from the editor pane. There
are already projects that go one better and attach an irb session to a
running program as a debug tool

4. Right clicking on a word and bringing up its help in an ri pane
should be doable, especially if your editor is written in ruby.

3. This is possibly hard to do portably, as it requires the ability to
run the program as a separate process, and either launch a terminal or
embed a terminal emulator. dragonconsole
[http://code.google.com/p/dragonconsole/] looks like a promising
cross-platform terminal emulator (it would require a java-based ide,
of course), or there could just be per-platform code to
fork/CreateProcess a terminal.

* Would this be a useful thing to have?

I think so - at the very least on windows, opening up a terminal
window to run stuff is not a natural thing to do, and I'm sure there
are lots of linux and mac users who would prefer a nice integrated
environment within which to learn ruby.

* Should it be written in ruby?

It would definitely be a nice-to-have, and would make things like irb
and ri integration a lot easier to do. Possible starting points:

- redcar (java/jruby based. Could potentially have its functionality
extended with existing widgets written in any jvm-based language)
- arcadia (ruby/tk. Not sure how easy it is to extend with existing
tcl/tk widgets)

The other point of view is that it might be better a to take a mature
ide with a large userbase and a powerful plugin system, and write
ruby-specific plugins for it. One huge plus is that it would bring
along version control integration for free.

Possible candidates there:

- eclipse or netbeans:
pro: very powerful
con: they have their own learning curve. not sure how easy it would be
to present a pared-down, ruby-specific interface.

promising lightweight, cross-platform ides with plugin systems include:
- jedit: plugins written in java. there is already a ruby development
plugin and a console plugin
- code::blocks: plugins written in c++ and squirrel (lua-inspired
dynamic oop scripting language)
- geany: plugins written in c or c++, seems like it currently has less
of a rich plugin ecosystem than the other two

Thoughts? Ideas?

martin