Adapted Valodim's capture completion script to

implement a simple completion service

autosuggestions.zsh

@@ -146,11 +146,13 @@ paused-autosuggest-self-insert() {
 }
 
 autosuggest-first-completion() {
+	local cursor=$CURSOR
 	zle .complete-word || return 1
+	CURSOR=$cursor
 }
 
 show-suggestion() {
-	[[ $LBUFFER == '' ]] && return
+	[[ -n $ZLE_DISABLE_AUTOSUGGEST || $LBUFFER == '' ]] && return
 	# TODO need a way to reset HISTNO so .history-beginning-search-backward
 	# will always retrieve the last matching history entry
 	# unset HISTNO

completion-service-init.zsh

@@ -0,0 +1,116 @@
+# Based on:
+# https://github.com/Valodim/zsh-capture-completion/blob/master/.zshrc
+
+# no prompt!
+PROMPT=
+
+# load completion system
+autoload compinit
+compinit
+
+# never run a command
+bindkey '\C-m' .kill-buffer
+bindkey '\C-j' .kill-buffer
+bindkey '\C-i' complete-word
+
+# send an emtpy line before completions are output
+empty-line() {
+	print
+	# handler needs to reinsert itself after being called
+	compprefuncs+=empty-line
+}
+compprefuncs+=empty-line
+
+# send a line with null-byte after completions are output
+null-line() {
+	print $'\0'
+	# handler needs to reinsert itself after being called
+	comppostfuncs+=null-line
+}
+comppostfuncs+=null-line
+
+zstyle ':completion:*' completer _complete
+# never group stuff!
+zstyle ':completion:*' list-grouped false
+# don't insert tab when attempting completion on empty line
+zstyle ':completion:*' insert-tab false
+# no list separator, this saves some stripping later on
+zstyle ':completion:*' list-separator ''
+# dont use matchers
+zstyle -d ':completion:*' matcher-list
+
+# we use zparseopts
+zmodload zsh/zutil
+
+# override compadd (this our hook)
+compadd () {
+
+	# check if any of -O, -A or -D are given
+	if [[ ${@[1,(i)(-|--)]} == *-(O|A|D)\ * ]]; then
+		# if that is the case, just delegate and leave
+		builtin compadd "$@"
+		return $?
+	fi
+
+	# be careful with namespacing here, we don't want to mess with stuff that
+	# should be passed to compadd!
+	typeset -a __hits __dscr __tmp
+
+	# do we have a description parameter?
+	# note we don't use zparseopts here because of combined option parameters
+	# with arguments like -default- confuse it.
+	if (( $@[(I)-d] )); then # kind of a hack, $+@[(r)-d] doesn't work because of line noise overload
+		# next param after -d
+		__tmp=${@[$[${@[(i)-d]}+1]]}
+		# description can be given as an array parameter name, or inline () array
+		if [[ $__tmp == \(* ]]; then
+			eval "__dscr=$__tmp"
+		else
+			__dscr=( "${(@P)__tmp}" )
+		fi
+	fi
+
+	# capture completions by injecting -A parameter into the compadd call.
+	# this takes care of matching for us.
+	builtin compadd -A __hits -D __dscr "$@"
+
+	# JESUS CHRIST IT TOOK ME FOREVER TO FIGURE OUT THIS OPTION WAS SET AND WAS MESSING WITH MY SHIT HERE
+	setopt localoptions norcexpandparam extendedglob
+
+	# extract prefixes and suffixes from compadd call. we can't do zsh's cool
+	# -r remove-func magic, but it's better than nothing.
+	typeset -A apre hpre hsuf asuf
+	zparseopts -E P:=apre p:=hpre S:=asuf s:=hsuf
+
+	# append / to directories? we are only emulating -f in a half-assed way
+	# here, but it's better than nothing.
+	integer dirsuf=0
+	# don't be fooled by -default- >.>
+	if [[ -z $hsuf && "${${@//-default-/}% -# *}" == *-[[:alnum:]]#f* ]]; then
+		dirsuf=1
+	fi
+
+	# just drop
+	[[ -n $__hits ]] || return
+
+	# this is the point where we have all matches in $__hits and all
+	# descriptions in $__dscr!
+
+	# display all matches
+	local dsuf dscr
+	for i in {1..$#__hits}; do
+
+		# add a dir suffix?
+		(( dirsuf )) && [[ -d $__hits[$i] ]] && dsuf=/ || dsuf=
+		# description to be displayed afterwards
+		# (( $#__dscr >= $i )) && dscr=" -- ${${__dscr[$i]}##$__hits[$i] #}" || dscr=
+
+		print $IPREFIX$apre$hpre$__hits[$i]$dsuf$hsuf$asuf$dscr
+
+	done
+
+	unset __hits __dscr __tmp
+}
+
+# signal the daemon we are ready for input
+print $'\0'

completion-service.zsh

@@ -0,0 +1,28 @@
+#!/bin/zsh
+# Based on:
+# https://github.com/Valodim/zsh-capture-completion/blob/master/capture.zsh
+
+zmodload zsh/zpty
+setopt noglob
+
+zpty z ZLE_DISABLE_AUTOSUGGEST=1 zsh -i
+
+# Source the init script
+zpty -w z "source '${0:a:h}/completion-service-init.zsh'"
+
+read-to-null() {
+	while zpty -r z chunk; do
+		[[ $chunk == *$'\0'* ]] && break
+		print -n $chunk
+	done
+}
+
+# wait for ok from shell
+read-to-null &> /dev/null
+
+while read prefix &> /dev/null; do
+	zpty -w -n z $prefix$'\t'
+	zpty -r z chunk &> /dev/null # read empty line before completions
+	read-to-null
+	zpty -w z $'\n'
+done