zsh/Completion/Core/_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 nullglob

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

local exp word sort expr expl subd suf=" " force opt

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

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

# First, see if we should insert all *completions*.

if [[ "$force" = *c* ]] ||
   { zstyle -s ":completion:${curcontext}:" completions expr &&
     [[ "${(e):-\$[$expr]}" -eq 1 ]] }; then
  compstate[insert]=all
  [[ "$curcontext" = expand-word:* ]] && _complete && return 0
  return 1
fi

# In exp we will collect the expansion.

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 [[ "$force" = *s* ]] ||
   { { zstyle -s ":completion:${curcontext}:" substitute expr ||
       { [[ "$curcontext" = expand-word:* ]] && expr=1 } } &&
         [[ "${(e):-\$[$expr]}" -eq 1 ]] }; then
  exp=( ${(f)"$(print -lR - ${(e)exp//\\[ 	
]/ })"} ) 2>/dev/null
else
  exp=( "${exp:s/\\\$/\$}" )
fi

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

(( $#exp )) || exp=("$word")

subd=("$exp[@]")

# Now try globbing.

[[ "$force" = *g* ]] ||
  { { zstyle -s ":completion:${curcontext}:" glob expr ||
      { [[ "$curcontext" = expand-word:* ]] && expr=1 } } &&
        [[ "${(e):-\$[$expr]}" -eq 1 ]] } &&
    exp=( ${~exp} )

# 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

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

# Now add as matches whatever the user requested.

zstyle -s ":completion:${curcontext}:" sort sort

[[ "$sort" = (yes|true|1|on) ]] && exp=( "${(@o)exp}" )

# If there is only one expansion, add a suitable suffix

if (( $#exp == 1 )); then
  if [[ -d $exp && "$exp[1]" != */ ]]; then
    suf=/
  elif zstyle -T ":completion:${curcontext}:" add-space; then
    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 _requested all-expansions expl 'all expansions'; then
    local disp dstr

    if [[ "${#${exp}}" -ge COLUMNS ]]; then
      disp=( -ld dstr )
      dstr=( "${(r:COLUMNS-5:)exp} ..." )
    else
      disp=()
    fi
    compadd "$disp[@]" "$expl[@]" -UQ -qS "$suf" - "$exp"
  fi
  if [[ $#exp -gt 1 ]] && _requested expansions; then
    local i normal 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=()
    dir=()

    for i in "$exp[@]"; do
      if [[ -d "$i" && "$i" != */ ]]; then
        dir=( "$dir[@]" "$i" )
      else
	normal=( "$normal[@]" "$i" )
      fi
    done
    (( $#dir ))    && compadd "$expl[@]" -UQ -qS/ -a dir
    (( $#normal )) && compadd "$expl[@]" -UQ -qS "$suf" -a normal
  fi

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

  compstate[insert]=menu
fi

return 0