Syntax coloring/highlighting in the REPL

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= problem =
Currently there is no syntax coloring/highlighting in the REPL.

= analysis =
Having syntax coloring/highlighting in the REPL would be very helpful for reading the code, spotting typos and other mistakes.

It would also be a great thing for beginners who are still learning the language and need some visual guidance.

= enhancement recommendation =
Add syntax coloring/highlighting to the REPL.

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Imported From: https://issues.scala-lang.org/browse/SI-4223?orig=1
Reporter: @soc
Assignee: @puffnfresh

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@paulp said:
Yeah, this would be cool.

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Luigi Plinge (rbj2001) said:
Something like they have on StackOverflow would be a lot better than nothing. Their scheme seems pretty simple: keywords dark blue, anything beginning with a capital letter light blue, numbers / anything between quotes or < > dark red, everything else black. (I haven't done more than a few minutes of analysis but this covers all examples I've looked at.)

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@soc said:
A simple, incremental improvement would be to have colored prompts, so that at least the definition and its results can be visually differentiated.

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Stefano Sgorlon (gokyo) said (edited on Feb 8, 2014 2:01:59 PM UTC):
I am looking at this issue. I try to fix it.
I will update you once I have good news :)

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@retronym said (edited on Sep 22, 2014 5:40:49 AM UTC):
Coloured prompts have been proposed by @puffnfresh in scala/scala#3993, assigning this ticket to him.

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@puffnfresh said:
Sounds like [~retronym] is happy to target the -Dscala.color flag for 2.11 but then change to JLine auto-detection in 2.12 so that we can get feedback on the bikeshed paint before committing to it?

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@puffnfresh said:
Think I'll write the auto-detection for Typelevel's scalac for our 2.11 compatible release, so we can test it out there.

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@retronym said:
Sounds GTM. wrt the color choice, it would be important to find defaults that works on dark and light terminals.

[SethTisue]

Ammonite has it, Dotty has it.