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Improve your arc REPL
30 points by emmett 914 days ago | 13 comments
I complained to Steve that arc didn't have readline support, which is one of the most annoying things that can happen to a shell. His response:

"use rlwrap foo!"

rlwrap is a simple readline wrapper which fixes this oversite. If you're using macports, port install rlwrap.

rlwrap mzscheme -m -f as.scm

And you have readline'd arc!



5 points by tlrobinson 913 days ago | link

rlwrap is freakin awesome. I think I probably would have killed myself by now without it.

Especially in Arc or any other Lispy language, since it does paren matching.

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3 points by cje 912 days ago | link

It breaks a bit on single-quotes, though -- rlwrap assumes they're matched, which usually isn't the case in lispy languages.

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4 points by bgutierrez 911 days ago | link

The latest version of rlwrap (0.30) lets you specify which characters are quote characters with the -q option.

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7 points by nex3 912 days ago | link

My current bin/arc:

  #!/bin/sh
  cd ~/src/arc0 && rlwrap -C arc mzscheme -m -f as.scm
The -C option gets it to have different history for arc and mzscheme.

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2 points by babo 912 days ago | link

  #!/bin/sh
  rlwrap -C arc mzscheme -m -e '(load/cd "~/src/arc0/as.scm")'

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3 points by soegaard 913 days ago | link

Current versions of mzscheme have builtin readline support:

  mzscheme -il readline
I can't remember whether readline support was introduced before or after version 352.

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1 point by etfb 911 days ago | link

Glorious! Thank you!

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2 points by parenthesis 912 days ago | link

And don't forget to customise your prompt string in procedure tl2 in ac.scm .

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1 point by offby1 912 days ago | link

I think he said "fool", not "foo!".

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1 point by lojic 912 days ago | link

Wow! rlwrap alone was worth checking out the Arc release - thanks for the tip :)

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1 point by chrisdone 912 days ago | link

Alternatively you can make MzScheme include readline in your .mzschemerc:

(when (regexp-match #rx"term" (or (getenv "TERM") "")) (dynamic-require '(lib "rep.ss" "readline") #f))

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2 points by mdemare 912 days ago | link

An installer for mzscheme would also be nice. Or just instructions about where to copy what.

And rlwrap is great, but any repl should have readline built-in.

Also, (quit) to exit is too cumbersome. ctrl-d doesn't work either. Apparently ctrl-c ctrl-d is the quickest solution.

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3 points by heath 912 days ago | link

I wrote most of the readline code for Chicken's REPL. I'll see what I can do about moving it over...

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