zsh/Completion/Base/Completer/_expand

#autoload

# This completer function is intended to be used as the first completer
# function and allows one to say more explicitly when and how the word
# from the line should be expanded than expand-or-complete.
# This function will allow other completer functions to be called if
# the expansions done produce no result or do not change the original
# word from the line.

setopt localoptions nonomatch

[[ _matcher_num -gt 1 ]] && return 1

local exp word sort expr expl subd suf=" " force opt asp tmp opre pre epre

(( $# )) &&
    while getopts gsco opt; do
      force="$force$opt"
    done

if [[ "$funcstack[2]" = _prefix ]]; then
  word="$IPREFIX$PREFIX$SUFFIX"
else
  word="$IPREFIX$PREFIX$SUFFIX$ISUFFIX"
fi

[[ "$word" = *\$(|\{[^\}]#) ||
   ( "$word" = *\$[a-zA-Z0-9_]## && $+parameters[${word##*\$}] -eq 0 ) ]] &&
    return 1

### I'm not sure about the pattern to use in the following test.
# It once was:
#  [[ "$word" = (\~*/|\$(|[=~#^+])[a-zA-Z0-9_\[\]]##[^a-zA-Z0-9_\[\]]|\$\{*\}?)[^\$\{\}\(\)\<\>?^*#~]# ]] &&

zstyle -T ":completion:${curcontext}:" suffix &&
  [[ "$word" = (\~*/*|*\$(|[=~#^+])[a-zA-Z0-9_\[\]]##[^a-zA-Z0-9_\[\]]|*\$\{*\}?) &&
     "${(e)word}" != *[][^*?\(\)\<\>\{\}\|]* ]] &&
  return 1

zstyle -t ":completion:${curcontext}:" accept-exact ||
  [[ $? -eq 2 && ! -o recexact ]] ||
  { [[ "$word" = \~(|[-+]) ||
       ( "$word" = \~[-+][1-9]## && $word[3,-1] -le $#dirstack ) ||
       ( "$word" = \~* && ${#userdirs[(I)${word[2,-1]}*]}+${#nameddirs[(I)${word[2,-1]}*]} -ne 1 ) ||
       ( "$word" = *\$[a-zA-Z0-9_]## && 
         ${#parameters[(I)${word##*\$}*]} -ne 1 ) ]] && return 1 }

# In exp we will collect the expansions.

exp=("$word")

# First try substitution. That weird thing spanning multiple lines
# changes quoted spaces, tabs, and newlines into spaces and protects
# this function from aborting on parse errors in the expansion.

if [[ "$force" = *s* ]] ||
   zstyle -T ":completion:${curcontext}:" substitute; then

###  We once used this:
###
###  [[ ! -o ignorebraces && "${#${exp}//[^\{]}" = "${#${exp}//[^\}]}" ]] &&
###      eval exp\=\( ${${(q)exp}:gs/\\{/\{/:gs/\\}/\}/} \) 2>/dev/null
###
###  instead of the following loop to expand braces.  But that made
###  parameter expressions such as ${foo} be expanded like brace
###  expansions, too (and with braceccl set...).

   if [[ ! -o ignorebraces && "${#${exp}//[^\{]}" = "${#${exp}//[^\}]}" ]]; then
     local otmp

     tmp=${(q)word}
     while [[ $#tmp != $#otmp ]]; do
       otmp=$tmp
       tmp=${tmp//(#b)\\\$\\\{(([^\{\}]|\\\\{|\\\\})#)([^\\])\\\}/\\$\\\\{${match[1]}${match[3]}\\\\}}
     done
     eval exp\=\( ${tmp:gs/\\{/\{/:gs/\\}/\}/} \) 2>/dev/null
   fi

###  There's a bug: spaces resulting from brace expansion are quoted in
###  the following expression, too.  We don't want that, but I have no
###  idea how to fix it.

  eval 'exp=( ${${(e)exp//\\[ 	
]/ }//(#b)([ 	
])/\\$match[1]} )' 2>/dev/null
else
  exp=( ${exp:s/\\\$/\$} )
fi

# If the array is empty, store the original string again.

[[ -z "$exp" ]] && exp=("$word")

subd=("$exp[@]")

# Now try globbing.

[[ "$force" = *g* ]] || zstyle -T ":completion:${curcontext}:" glob &&
    eval 'exp=( ${~exp//(#b)\\[ 	
]/$match[1]} ); exp=( ${(q)exp} )' 2>/dev/null

### Don't remember why we once used this instead of the (q) above.
#    eval 'exp=( ${~exp} ); exp=( ${exp//(#b)([][()|*?^#~<>\\=])/\\${match[1]}} )' 2>/dev/null

# If we don't have any expansions or only one and that is the same
# as the original string, we let other completers run.

(( $#exp )) || exp=("$subd[@]")

[[ $#exp -eq 1 && "${exp[1]//\\}" = "${word//\\}"(|\(N\)) ]] && return 1

# With subst-globs-only we bail out if there were no glob expansions,
# regardless of any substitutions

{ [[ "$force" = *o* ]] ||
  zstyle -t ":completion:${curcontext}:" subst-globs-only } &&
  [[ "$subd" = "$exp"(|\(N\)) ]] &&  return 1

zstyle -s ":completion:${curcontext}:" keep-prefix tmp || tmp=changed

if [[ "$word" = (\~*/*|*\$*/*) && "$tmp" = (yes|true|on|1|changed) ]]; then
  if [[ "$word" = *\$* ]]; then
    opre="${(M)word##*\$[^/]##/}"
  else
    opre="${word%%/*}"
  fi
  eval 'epre=( ${(e)~opre} )' 2> /dev/null

  if [[ -n "$epre" && $#epre -eq 1 ]]; then
    pre="${(q)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 ${exp[1]/${opre}/${pre}} && "$exp[1]" != */ ]]; then
    suf=/
  elif [[ "$asp" = yes* ||
          ( "$asp" = *file && -f "${exp[1]/${opre}/${pre}}" ) ]]; then
    suf=' '
  else
    suf=
  fi
fi

if [[ -z "$compstate[insert]" ]] ;then
  if [[ "$sort" = menu ]]; then
    _description expansions expl expansions "o:$word"
  else
    _description -V expansions expl expansions "o:$word"
  fi

  compadd "$expl[@]" -UQ -qS "$suf" -a exp
else
  _tags all-expansions expansions original

  if [[ $#exp -gt 1 ]] && _requested expansions; then
    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
    normal=()
    space=()
    dir=()

    for i in "$exp[@]"; do
      j="${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
    (( $#space ))  && compadd "$expl[@]" -UQ -qS " " -a space
    (( $#normal )) && compadd "$expl[@]" -UQ -qS "" -a normal
  fi
  if _requested all-expansions expl 'all expansions'; then
    local disp dstr

    if [[ "${#${exp}}" -ge COLUMNS ]]; then
      disp=( -ld dstr )
      dstr=( "${(r:COLUMNS-5:)exp} ..." )
    else
      disp=()
    fi
    [[ -o multios ]] && exp=($exp[1] $compstate[redirect]${^exp[2,-1]})
    compadd "$disp[@]" "$expl[@]" -UQ -qS "$suf" - "$exp"
  fi

  _requested original expl original && compadd "$expl[@]" -UQ - "$word"

  compstate[insert]=menu
fi

return 0