DUB colored output proposal/showcase

[gdelazzari]

On Friday, 8 June 2018 at 15:34:06 UTC, Uknown wrote:
> I love it! I have very little experience with terminal colours, 
> but as far as colourizing text on POSIX its fairly easy. You 
> just need to emit the right ANSI escape sequences [0]. This is 
> what the colorize-d library does.. For Windows before Windows 
> 10, things are more messy. You need to use `handle`s, to get 
> the current state and then correctly set the colours. The real 
> hard part here is adjusting the colour scheme based on the 
> terminal background colour.
>
> [0]: https://en.wikipedia.org/wiki/ANSI_escape_code#Colors

Sure, I sort of know how that works, I did some stuff some time 
ago. Also, regarding Windows, the colorize-d library already 
handles what you described. I think I'll simply take the source 
of colorize-d and copy-paste the files in the Dub source, as I 
saw they've done with some parts of Vibe.d in order to avoid 
having to fetch Dub packages while compiling Dub itself.

> I would love to help you on this. Is there anything in 
> particular you need help with?

Actually, it's not a difficult task. But, being a bit of a 
perfectionst, I already spotted the possibility of writing a 
separate module handling all the terminal output, in order to 
better separate things. At the moment Dub uses the log module 
from Vibe.d (as I wrote before, which it seems they've just 
copy-pasted in dub/internal/vibecompat/core/log.d) to print stuff 
to the terminal, I think replacing it with a module that handles 
colors and "tags" like in the screenshots I attacched would be 
the best option. But in order to do something like this cleanly 
we should first define well how to structure the output and thus 
the module handling it. Also documenting stuff a bit. Then we'll 
need to replace all the calls to logInfo, logDiagnostic, 
logError, etc... in the entire codebase :P

A quicker option is to just leave the log calls there, add the 
escape sequences in order to color the wanted words (as it's 
currently done in the proof-of-concept) and then fix the Vibe.d 
log module to handle colors on Windows with the same "workaround" 
that colorize-d uses. That's a faster way indeed, but a bit dirty 
IMHO. Also, to handle different color schemes (for MacOS/white 
background terminals) it may become a mess.

So, having a module which handles all the terminal output seems 
the best option to me, if we want to do stuff cleanly. The main 
problem is to define its requirements, how it should interface 
with the rest of the code, how to structure it, etc... then 
writing the code is the simplest part, as always. I can handle 
this by myself, but if anyone wants to help that would be really 
appreciated, especially on planning how to structure the changes. 
Maybe we can discuss about the implementation on IRC or some 
other platform?