Re: global aliases substituting *within* a path

[Bart Schaefer <schaefer@brasslantern.com>]

On May 18,  3:08pm, Ronald Fischer wrote:
}
} > echo a/f/b/b/x<TAB>
} 
} Doesn't help here, for two reason:
} 
} (1) At least in my version of zsh (4.3.12), this would not expand the
} interim directories (f,b,b).

Does your zsh configuration include installing the completion system
(the "compinit" command)?

} (2) Even if I could do TAB completion on directories within the path,
} this is not what I'm looking for, because it is still cumbersome to
} type.

You might want to look at named directories:

    hash -d aaa=aaa/foo/bar/baz
    hash -d bbb=bbb/foo/bar/baz
    hash -d ccc=ccc/foo/bar/baz

Then you can write

    ls ~aaa/xxx
    ls ~bbb/yyy
    ls ~ccc/zzz

I don't know how much variation there is in the "foo/bar/baz" part of
your structure.  You can try using dynamic named directories:

    X=foo/bar/baz
    ls ~[aaa/X]/xxx

That's not saving any keystrokes over aaa/$X/xxx but might have some
aesthetic advantages.  It's implemented with something like this:

    stem_name_hook() {
	case $1 in
        (n) local root=$2:h stem=$2:t
            reply=( $root/${(P)stem} )
	    ;;
	(*) return 1;
	esac
    }

    autoload -Uz add-zsh-hook
    add-zsh-hook zsh_directory_name stem_name_hook

The above allows ANY leading path (the "root") and ANY variable name (the
"stem") after the slash to be the "middle of the path", e.g.

    Y=fare/thee/well
    ls ~[/usr/local/Y]/yyy

You could of course apply a similar transformation on the root instead
(or as well) but that's not much different than ordinary "hash -d" with
perhaps auto_name_dirs enabled.

If you want to be able to use it in completions and other automatic path
contractions, you need a reverse mapping that provides a sensible set of
root and stem names.  Here's one that uses ONLY aaa, bbb, ccc for roots
and ONLY $X for the stem:

    stem_name_hook() {
	case $1 in 
	(n) reply=( $2:h/$X )
	    ;;
	(d) reply=( ${2/\/$X(\/*|)/\/X})
	    reply=($reply ${#reply[1]} )
	    ;;
	(c) local dirs
	    dirs=( (aaa|bbb|ccc)/$X )
	    if (( $#dirs )); then
		dirs=( ${^dirs%$X}X )
		_wanted dynamic-dirs expl 'dynamic directory' \
		    compadd -S \] -a dirs
	    else
	        return 1
	    fi
	    ;;
	(*) return 1;
	esac
    }

I'm not entirely sure about that (c) branch, which is for compsys [cf.
my response to (1)].  PWS is the expert on dynamic directory hooks.

-- 
Barton E. Schaefer