Re: how to make zsh tab-complete path after colon (instead of just `=`)

[Daniel Shahaf <d.s@xxxxxxxxxxxxxxxxxx>]

Peter Stephenson wrote on Tue, Jan 08, 2019 at 12:37:31 +0000:
> I'm told this is probably good enough, and it's certainly not a big
> change, and it's safe if you don't have the style set, so we might as
> well get it in.

I'm not convinced we should.

The functionality provided is extremely specific (only file completion;
only single characters as the delimiter; etc).  It is also "brutal" (to
use your word), to the point that even the new documentation recommends
against using it.  Moreover, it could be implemented equivalently by
a short and equally brutal zshrc change (fewer than 10 lines), with
no changes to the completion standard library.

The new functionality does not make _path_files easier to maintain (it
adds four lines that everyone who changes this function from now one
will have to decipher) nor the manual easier to use (it reduces the
signal-to-noise ratio by adding a feature that self-describes as one
that shouldn't normally be used).

If we add and document this now, we'll be committed to supporting it for
eternity, and I am unsure that the added value justifies the cost.

I see you've pushed this already, so I would ask not to ship 5.7 with
this patch this week, in order to give time for discussion before the
backwards compatibility milk spills.

Cheers,

Daniel

> Someone may see some useful tweaks, e.g. it's quite possible I haven't
> taken account of quoting properly.  Here's a full patch with
> documentation.
> 
> pws
> 
> diff --git a/Completion/Unix/Type/_path_files b/Completion/Unix/Type/_path_files
> index 9fa6ae9..1021c34 100644
> --- a/Completion/Unix/Type/_path_files
> +++ b/Completion/Unix/Type/_path_files
> @@ -2,6 +2,11 @@
>  
>  local -a match mbegin mend
>  
> +local splitchars
> +if zstyle -s ":completion:${curcontext}:" file-split-chars splitchars; then
> +  compset -P "*[${(q)splitchars}]"
> +fi
> +
>  # Look for glob qualifiers.  Do this first:  if we're really
>  # in a glob qualifier, we don't actually want to expand
>  # the earlier part of the path.  We can't expand inside
> diff --git a/Doc/Zsh/compsys.yo b/Doc/Zsh/compsys.yo
> index a5a9e5b..3ce1c8c 100644
> --- a/Doc/Zsh/compsys.yo
> +++ b/Doc/Zsh/compsys.yo
> @@ -1568,6 +1568,16 @@ contains the string `tt(follow)', timestamps are associated with the
>  targets of symbolic links; the default is to use the timestamps
>  of the links themselves.
>  )
> +kindex(file-split-chars, completion style)
> +item(tt(file-split-chars))(
> +A set of characters that will cause em(all) file completions for
> +the given context to be split at the point where any of the characters
> +occurs.  A typical use is to set the style to tt(:); then everything
> +up to and including the last tt(:) in the string so far is ignored when
> +completing files.  As this is quite heavy-handed, it is usually
> +preferable to update completion functions for contexts where this
> +behaviour is useful.
> +)
>  kindex(filter, completion style)
>  item(tt(filter))(
>  The tt(ldap) plugin of email address completion (see tt(_email_addresses)) uses