Fmt_cli (fmt.Fmt

Option for setting the style renderer

val style_renderer : 
  ?env:Cmdliner.Arg.env ->
  ?docs:string ->
  unit ->
  Fmt.style_renderer option Cmdliner.Term.t

style_renderer ?env ?docs () is a Cmdliner option --color that can be directly used with the optional arguments of TTY setup or to control style rendering. The option is documented under docs (defaults to the default in Cmdliner.Arg.info).

The option is a tri-state enumerated value that when used with TTY setup takes over the automatic setup:

--color=never, the value is Some `None, forces no styling.
--color=always, the value is Some `Ansi, forces ANSI styling.
--color=auto or absent, the value is None, automatic setup takes place.

If env is provided, the option default value (None) can be overridden by the corresponding environment variable.