[TxMt] Interactive Shell for irb

Hans-Jörg Bibiko bibiko at eva.mpg.de
Sat Dec 22 13:08:55 UTC 2007

> On 21.12.2007, at 20:18, Thomas Aylott - subtleGradient wrote:
>> On Dec 21, 2007, at 8:39 AM, Hans-Jörg Bibiko wrote:
>>> after fixing to run R inside of TM as interactive shell I tried  
>>> to run irb and it also works. But one 'only' has to change the  
>>> communication between irb and TM slightly. Is someone interested  
>>> to do that? ;)
>> DO WHAT?!!!!1! :O
>> Please don't tease us here. You can run IRB interactively from  
>> within TextMate? How?
>> What do we need to do to make that work?
> Give me a moment. I will try to modify a bit in order to show  
> something basic.

Hi, here comes at least a screencast of an IRBdaemon. To be honest,  
I've never used all of irb's possibilities but the basics seem to work.

http://www.bibiko.de/irbdaemon.mov (600kB)

My general approach – in very short terms:

If I have an application which runs in a normal Terminal without any  
graphical environment (including such as Midnight Commander, vi,  
etc.) **AND** I can find a definable return pattern coming from that  
application then I can do the following.

Example for R but it's also applicable in modified form to irb, etc.

If I run R in a Terminal I will have a prompt '> ', I can type a  
command '2+3',
press RETURN, and R writes into that Terminal '[1] 5\n> '.
Now I run R in a pseudo terminal (meaning a terminal which is hidden  
for the user) using Ruby's lib 'pty' (a spawned process).
The output of that pseudo terminal will be written into ~/Rdaemon/ 
r_out (together with stderr).
Then I created in beforehand a named pipe on ~/Rdaemon/r_in. Into  
that pipe I send all commands coming from TM or elsewhere.

Here the daemon as simplified version:

cmd = "R 2&> ~/Rdaemon/r_out"
PTY.spawn(cmd) { |r,w,pid|
	# write r into the nirvana
	Thread.new {r.read}
	fin = File.open('~/Rdaemon/r_in', "r+")
	while TRUE
		#wait for a new task and send it to R
		task = fin.gets
		w.puts task

That means the named pipe r_in is my keyboard and r_out is the  
terminal content

Before I send a command to r_in I look for the end of r_out. Then,  
after sending, the Rdaemon wrote something into r_out. I wait until R  
wrote at the end the pattern '> ' (synchronization). Then I only take  
the new piece of r_out and I insert it as snippet (fine-tuned for irb  
because irb has a changeable prompt). That's it.
The daemon runs in a while TRUE loop. Caused by the line 'task =  
fin.gets' this process needs no cpu while waiting.
If I send 'quit' to r_in it destroys itself.


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