PATCH: Re: expansion

[Sven Wischnowsky <wischnow@xxxxxxxxxxxxxxxxxxxxxxx>]

Bart Schaefer wrote:

> On Jun 7,  8:46am, Sven Wischnowsky wrote:
>
> ...
> 
> } But then I would insist, that we change add-space to:
> } 
> }   - true: always add a space (after all, one might want to use it to
> }            generate names of non-existing files)
> }   - false: never add a space
> }   - exisiting: add a space only if the word is the name of an
> }            exisiting file
> } 
> } Ok?
> 
> Whether that is "ok" depends more on what the behavior is when it is not
> set at all than on what the possible settings are.

The patch below makes the default `file' (I used that instead of the
longish `existing'). But that's easy to change.


> } Maybe we should add to this: add a space if the thing comes from a
> } parameter expansion even if it isn't the name of an existing file.
> 
> How about a simplified rule of "add a space whenever completion would."
> 
> Of course that's probably a much more complicated *implementation* ...

I'm not sure what you mean. Completion (which, in my book, is
something completely different than expansion, but...) *always* adds a 
space, unless it's a directory and it completed filenames or there is
some other kind of suffix, most of which are only useful with
completion, I think.

Anyway, the patch also allows `add-space' to contain `subst', combined 
with either `true' or `file' to say that it shouldn't add the space if 
some kind of substitution was involved.


Peter Stephenson wrote:

> How about something like this?  The style keep-tilde defaults to on and
> makes _expand restore the ~/ or ~foo/ part of an expression after globbing.
> It doesn't need to default to on.  It could probably usefully take a third
> value indicating you would like the ~ expanded if there were no other
> changes --- that might be a good default.

Wonderful, I wrote something similar yesterday evening -- and called
it `keep-prefix'. I've now also added that third value you suggest
(I've called it `change') and made it the default. Again, that's easy
to change.

> I won't commit this because I'm sure someone will have suggestions for
> expansions, deletions, changes, or complete rewrites.  For example, you
> could restore initial parameter expressions such as ${HOME}/ in a similar
> way if the glob succeeded (or subst-globs-only is true).  But we could do
> with something or other along these lines.

It's called `keep-prefix' because it tries to do that. But the pattern 
matching is *very* simple currently, so that it will not catch all
complicated parameter expansions. That could be improved.

> It's a different question, but maybe we could set nonomatch for the
> duration of the function to handle failed matches more gracefully.  Or
> maybe people who don't set nonomatch (i.e. do set no nonomatch) like it the
> way it is.

Oops. Yes, good idea. Maybe we should also take the code we use
elsewhere when expanding ~unknown/foo to complain about an unknown
user/dir.


I'll commit this patch, in the hope that it will be easier to get the
behaviour that finally makes most people happy with it.

Bye
 Sven

Index: Completion/Core/_expand
===================================================================
RCS file: /cvsroot/zsh/zsh/Completion/Core/_expand,v
retrieving revision 1.14
diff -u -r1.14 _expand
--- Completion/Core/_expand	2000/06/06 13:04:10	1.14
+++ Completion/Core/_expand	2000/06/08 08:35:44
@@ -7,11 +7,11 @@
 # the expansions done produce no result or do not change the original
 # word from the line.
 
-setopt localoptions nullglob
+setopt localoptions nullglob nonomatch
 
 [[ _matcher_num -gt 1 ]] && return 1
 
-local exp word sort expr expl subd suf=" " force opt
+local exp word sort expr expl subd suf=" " force opt asp tmp opre pre epre
 
 (( $# )) &&
     while getopts gsco opt; do
@@ -46,8 +46,8 @@
    { { zstyle -s ":completion:${curcontext}:" substitute expr ||
        { [[ "$curcontext" = expand-word:* ]] && expr=1 } } &&
          [[ "${(e):-\$[$expr]}" -eq 1 ]] }; then
-  exp=( ${(f)"$(print -lR - ${(e)exp//\\[ 	
-]/ })"} ) 2>/dev/null
+  exp=( "${(e)exp//\\[ 	
+]/ }" )
 else
   exp=( "${exp:s/\\\$/\$}" )
 fi
@@ -81,18 +81,42 @@
       [[ "${(e):-\$[$expr]}" -eq 1 ]] } && 
         [[ "$subd" = "$exp"(|\(N\)) ]] && return 1
 
+zstyle -s ":completion:${curcontext}:" keep-prefix tmp || tmp=changed
+if [[ "$word" = [\~\$]*/* && "$tmp" = (yes|true|on|1|changed) ]]; then
+  epre=( ${(e)~${word%%/*}} )
+  if [[ -n "$epre" && $#epre -eq 1 ]]; then
+    opre="${word%%/*}"
+    pre="$epre[1]"
+    [[ "$tmp" != changed || $#exp -gt 1 ||
+       "${opre}${exp[1]#${pre}}" != "$word" ]] && exp=( ${opre}${^exp#${pre}} )
+  fi
+  [[ $#exp -eq 1 && "$exp[1]" = "$word" ]] && return 1
+fi
+
 # Now add as matches whatever the user requested.
 
 zstyle -s ":completion:${curcontext}:" sort sort
 
 [[ "$sort" = (yes|true|1|on) ]] && exp=( "${(@o)exp}" )
 
+if zstyle -s ":completion:${curcontext}:" add-space tmp; then
+  if [[ "$tmp" != *subst* || "$word" != *\$* || "$exp[1]" = *\$* ]]; then
+    [[ "$tmp" = *file* ]] && asp=file
+    [[ "$tmp" = *(yes|true|1|on|subst)* ]] && asp="yes$asp"
+  fi
+else
+  asp=file
+fi
+
 # If there is only one expansion, add a suitable suffix
 
 if (( $#exp == 1 )); then
-  if [[ -d $exp && "$exp[1]" != */ ]]; then
+  if [[ -d ${exp[1]/${opre}/${pre}} && "$exp[1]" != */ ]]; then
     suf=/
-  elif ! zstyle -T ":completion:${curcontext}:" add-space; then
+  elif [[ "$asp" = yes* ||
+          ( "$asp" = *file && -f "${exp[1]/${opre}/${pre}}" ) ]]; then
+    suf=' '
+  else
     suf=
   fi
 fi
@@ -120,30 +144,30 @@
     compadd "$disp[@]" "$expl[@]" -UQ -qS "$suf" - "$exp"
   fi
   if [[ $#exp -gt 1 ]] && _requested expansions; then
-    local i normal dir
+    local i j normal space dir
 
     if [[ "$sort" = menu ]]; then
       _description expansions expl expansions "o:$word"
     else
       _description -V expansions expl expansions "o:$word"
     fi
-    if zstyle -T ":completion:${curcontext}:" add-space; then
-      suf=' '
-    else
-      suf=
-    fi
     normal=()
+    space=()
     dir=()
 
     for i in "$exp[@]"; do
-      if [[ -d "$i" && "$i" != */ ]]; then
+      j="${i/${opre}/${pre}}"
+      if [[ -d "$j" && "$i" != */ ]]; then
         dir=( "$dir[@]" "$i" )
+      elif [[ "$asp" = yes* || ( "$asp" = *file && -f "$j" ) ]]; then
+        space=( "$space[@]" "$i" )
       else
 	normal=( "$normal[@]" "$i" )
       fi
     done
     (( $#dir ))    && compadd "$expl[@]" -UQ -qS/ -a dir
-    (( $#normal )) && compadd "$expl[@]" -UQ -qS "$suf" -a normal
+    (( $#space ))  && compadd "$expl[@]" -UQ -qS " " -a space
+    (( $#normal )) && compadd "$expl[@]" -UQ -qS "" -a normal
   fi
 
   _requested original expl original && compadd "$expl[@]" -UQ - "$word"
Index: Doc/Zsh/compsys.yo
===================================================================
RCS file: /cvsroot/zsh/zsh/Doc/Zsh/compsys.yo,v
retrieving revision 1.59
diff -u -r1.59 compsys.yo
--- Doc/Zsh/compsys.yo	2000/05/29 14:48:38	1.59
+++ Doc/Zsh/compsys.yo	2000/06/08 08:35:46
@@ -784,10 +784,15 @@
 item(tt(add-space))(
 This style is used by the tt(_expand) completer.  If it is `true' (the
 default), a space will be inserted after all words resulting from the 
-expansion (except for directory names which get a slash).
+expansion (except for directory names which get a slash).  The value
+may also be the string `tt(file)' to make the completer add a space
+only to names of existing files.  Finally, the `true' values and
+`tt(file)' may be combined with `tt(subst)' to keep the completer from 
+adding a space when the resulting words were generated by expanding a
+substitution such as `tt($LPAR()...RPAR())' and `tt(${...})'.
 
-It is also used by the tt(_prefix) completer to decide if a space should
-be inserted before the suffix.
+It is also used by the tt(_prefix) completer as a simple boolean value
+to decide if a space should be inserted before the suffix.
 )
 kindex(ambiguous, completion style)
 item(tt(ambiguous))(
@@ -1282,6 +1287,22 @@
 in the context name to one of tt(correct-)var(num) or
 tt(approximate-)var(num), where var(num) is the number of errors that
 were accepted.
+)
+kindex(keep-prefix, completion style)
+item(tt(keep-prefix))(
+This style is used by the tt(_expand) completer.  If it is `true', the
+completer will try to keep a prefix containing a tilde or parameter
+expansion.  I.e., the string `tt(~/f*)' would be expanded to
+`tt(~/foo)' instead of `tt(/home/user/foo)'.  If the style is set to
+`tt(changed)' (the default), the prefix will only be left unchanged if
+there were other changes between the expanded words and the original
+word from the command line.  Any other value makes the prefix be
+expanded unconditionally.
+
+Note that with one of the `true' values, the tt(_expand) completer
+returns if there is only one expansion and that is, after restoring
+the original prefix, the same as the original word.  This means that
+other completers will be called immediately after tt(_expand).
 )
 kindex(last-prompt, completion style)
 item(tt(last-prompt))(

--
Sven Wischnowsky                         wischnow@xxxxxxxxxxxxxxxxxxxxxxx