Re: which-command help

[Peter Stephenson <pws@csr.com>]

Bart Schaefer wrote:
> On May 17,  3:47pm, Peter Stephenson wrote:
> } Subject: Re: which-command help
> }
> } > # but if I use "^[?" (is which-command) I get:
> } > 
> } >  ~ % which-command /bin/ls
> } > /bin/ls
> } 
> } The problem is that the processing of which-command within the editor
> } expands the alias, so that the command line that which-command sees
> } already has the /bin/ls expanded.
> } 
> } I think this is a bug, fixed below: we don't want to expand aliases when
> } getting the name of the command.
> 
> Compare zsh-workers/20895 and surrounding thread.  Are we breaking one
> thing to fix another?

Well, your reply in that message was:

> Suppose you have
> 
>   alias LL='ls -lL'
> 
> Do you want run-help to display the man page for "ls", or do you want it
> to simply fail because there is no LL command?

Actually, it *doesn't* fail after the patch:

% alias LL='ls -lL'
% which-command LL
ls -lL

I would have said that's more useful, because it's clearer about what's
going on (even more so if which-command is aliased to something more
verbose).  However, I'm certainly not set on the patch.  I would be
happy to suggest using the editor widget instead.  That could even be
modified to expand the alias and lookup the first word as a command,
noting that aliases work recursively:

which-command() {
  zmodload -i zsh/parameter

  zle -I
  local -a wds
  wds=(${(z)LBUFFER})
  local wd=${wds[1]}
  local rawwd=${(Q)wd}
  local -A seen

  while true; do
    wd=${wds[1]}
    rawwd=${(Q)wd}

    # replace "whence -c" with your favourite function
    # (but NOT which-command!)
    if [[ $rawwd != $wd || -n $seen[$rawwd] ]]; then
      # quoted or already expanded, don't expand alias
      (unalias -- $rawwd 2>/dev/null; whence -c $rawwd)
    else
      # turn on globsubst for =ls etc.
      whence -c ${~rawwd}
      if [[ -n $aliases[$rawwd] && -z $seen[$rawwd] ]]; then
        # Recursively expand aliases
        seen[$rawwd]=1
        wds=(${(z)aliases[$rawwd]})
	continue
      fi
    fi
    break
  done
}

This might be worth sticking in Functions/Zle.

-- 
Peter Stephenson <pws@csr.com>                  Software Engineer
CSR PLC, Churchill House, Cambridge Business Park, Cowley Road
Cambridge, CB4 0WZ, UK                          Tel: +44 (0)1223 692070


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