feature request: colorize * in error report

[dgreisen]

It would be hugely helpful if the * indicating where the parser failed were bright red. I hacked something together for arpeggio with regexp and http://click.pocoo.org/5/utils/#ansi-colors, but it would be great if this were built in to parglare.

[dgreisen]

While improving display, it would also be helpful to improve the debugger output:

• add color to the headings (token ahead:, context:, etc)
• indent and wrap text nicely using https://docs.python.org/2/library/textwrap.html
• add a hard return between each state so there is more visual definition

[igordejanovic]

Great idea. It should improve trace readability a lot. I try to keep dependencies low.
These deps could be optional (e.g. with fallback to current behaviour) and used only in development mode.

[dgreisen]

My understanding is that behind the scenes it's just adding special control characters. You might just be able to grab https://github.com/pallets/click/blob/master/click/termui.py#L335 and the unstyle function and be good to go.

[igordejanovic]

Yes, I guess you are right. click uses 3-clause BSD licence so it is compatible with MIT and shouldn't be a problem to take just the needed bits of code while keeping the copyright notice.

[igordejanovic]

@dgreisen This is implemented on the master. There is now a param debug_colors for Parser/GLRParser and Grammar.from_string/from_file. By default it is False.

For pglr command coloring is enabled by default. You can disable it by --no-colors switch. click module is now used to implement pglr cli so the command is changed a bit.