Color your terminal's output

[Jens Mueller]

Johannes Pfau wrote:
> Jens Mueller wrote:
> >Hi,
> >
> >I started writing a simple module to color terminal output some time
> >ago. In a recent thread people seemed interested in having such
> >functionality. I cleaned up this code and kindly ask whether such a
> >module is considered a useful addition.
> >
> >On Posix systems it uses 4 Curses functions and on Windows systems the
> >Windows API is used. I tested it on Linux (using different terminal
> >emulators) and on Windows XP.
> >It allows setting foreground and background colors and setting bold,
> >underline, reverse and blink font faces.
> >Get the code from
> >https://raw.github.com/jkm/phobos/terminal/std/terminal.d
> >
> >To test (hopefully filling your terminal with colored output) run
> >on Posix
> >32 bit
> >$ dmd -unittest -m32 /usr/lib/libncurses.a -run terminal.d
> >64 bit
> >$ dmd -unittest -m64 /usr/lib/libncurses.a -run terminal.d
> >
> >(The library path may need to be adjusted.)
> >
> >and on Windows
> >$ dmd -unittest -run terminal.d
> >
> >At this point there are some issues that I need to figure out, namely:
> >* Is there a portable way to unset font face attributes on Posix?
> >* How to portably obtain the default foreground/background color on
> >  Posix?
> >* How to properly test such a module?
> >* Possible license problems: I have no idea whether it's allowed to
> >link
> >  against whatever license (the curses implementation uses). In doubt I
> >  need to use the license that I link against, I suppose.
> 
> You could use ANSI codes on posix to avoid a dependency on curses:
> http://en.wikipedia.org/wiki/ANSI_escape_code#Colors
> But I think using curses is ok. ncurses is MIT licensed and can be
> used as a dynamic library, so I don't think there are license problems.
> 
> However, I'd recommend to load ncurses dynamically with dlopen/dlsym
> and fallback to simple text output if the ncurses library cannot be
> loaded.

Using the ANSI codes is fine with me. I assumed they aren't that
portable but it seems fine.

> >Any help is very appreciated.
> >
> >Though this module is functionality-wise inferior to something like
> >ncurses it conveniently allows coloring output for most use cases.
> 
> as you already use these functions:
> http://linux.die.net/man/3/setupterm
> it'd be nice to have wget-like progressbars and 'updateable' text
> labels. Shouldn't be as fancy as full ncurses, for most use cases it's
> good enough to modify the current line. +Points if it properly handles
> terminal width and resizing.

I believe progress bars are easy to add. Boost's progress_bar should be
fairly easy to port. It'll be nice if you could provide a pull request
for this. Is this feasible for you?
Regarding update able text labels I'm not sure how they are typically
used. So I would also prefer some pull request from somebody with a
common use case.
I'm just pushing this color support because I'm using it in some tool.
And it may be useful to others. I believe it's a good thing to add the
features you need for your project via a pull request.

Jens