Re: Best way to test for zsh features?

[Peter Stephenson <pws@xxxxxxx>]

john_oshea@xxxxxxxxxxxx wrote:
> What's the best/cleanest/most "correct" way of checking for zsh features
> in an .zshrc? I've started to use vcs_info as part of my prompt, which
> works wonderfully in zsh's new enough to have that available, but gives
> me "function definition file not found" on machines with older zsh
> installations (that I'm unable to upgrade).

If the feature you're testing for is a function, it's quite easy to
define a function to look for the corresponding file.

  function_exists () {
    local -a files
    # This expands occurrences of $1 anywhere in $fpath,
    # removing files that don't exist.
    files=(${^fpath}/$1(N))
    # Success if any files exist.
    (( ${#files} ))
  }

You can now use this in tests:

  if function_exists vcs_info; then
    ...
  fi

-- 
Peter Stephenson <pws@xxxxxxx>            Software Engineer
Tel: +44 (0)1223 692070                   Cambridge Silicon Radio Limited
Churchill House, Cambridge Business Park, Cowley Road, Cambridge, CB4 0WZ, UK


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