Make --color a shakeOption

[nh2]

I would like to enable colouring by default using shakeOptions; it is not exposed there yet.

Also: Colours are great, they should be on by default! A bit of green makes your build system feel much friendlier.

[nh2]

(Alternatively to making it an option, outputColor could be exposed so that I can set { shakeOutput = outputColor }.

[nh2]

Also, in shakeOpts = foldl (flip ($)) baseOpts flagsShake: Granted that the flags list is short, but wouldn't foldl' be better for any case where you actually want to use the whole list?

[ndmitchell]

First rule of programming, never assume command line arguments are short - every time I've done that someone has piped several Mb through the arguments (seriously, it's happened about 5 times). I've switched to foldl'.

I suspect that exposing outputColor is a better choice than adding a new member to ShakeOption. However, it doesn't currently work on Windows, which I would want to fix before exposing it. There are some docs on how that could work (see http://stackoverflow.com/a/8285944/160673) and some of that could be generalised with the Progress stuff that already uses escape sequences or console functions depending on platform.

Once it is available everywhere easily, then I can think about making it the default. In general very few programs use color by default, in particular make doesn't, and my command line flags and behaviour are make compatible by default, suggesting I shouldn't. However, there are standard conventions like picking up extra flags out of an environment variable, which I'd be quite happy to add.

In the meantime, you can easily work around this by using withArgs to customise the arguments before they get to Shake and just tack on --color. It's not beautiful, but it should work - I do this all the time in the Shake test suite.

[nh2]

Once it is available everywhere easily, then I can think about making it the default. In general very few programs use color by default, in particular make doesn't

make was there before colours where invented :P

just tack on --color

Yes, using

withColors f = do args <- getArgs
                  withArgs ("--color":args) f

withColors $ shakeStuff ...

now.

[ndmitchell]

Note that npm, part of Node.js, uses colored text on Windows in the standard console quite successfully, so I can always copy what they are doing.

[Mathnerd314]

ansi-terminal implements cross-platform colors. It also provides setTitle, so that code can go away (except for the xterm check).

[ndmitchell]

@Mathnerd314 @feuerbach - very cool, clear interface, minimal dependencies, looks like it provides what I need. However, a quick try shows it works nicely in the Windows console, but not so well in Cygwin bash console on Windows. I'll see if I can figure out why, and if I can fix that up, it would make implementing colors much easier.

[ndmitchell]

Trying ansi-terminal again with the included demo, it works perfectly in all situations (could well have been my old cygwin installation that had the issues). I should definitely switch over.

[23Skidoo]

There should also be a --no-colour option, or at least some way of disabling colouring programmatically. --colour is quite useless right now, since it's enabled by default.