#!/usr/bin/env zsh
#
# Based on https://github.com/romkatv/run-process-tree but without
# the preservation of options, patterns, etc.

emulate -L zsh                                           || return
setopt monitor traps_async pipe_fail no_unset no_bg_nice || return
zmodload zsh/system                                      || return

local stdout REPLY
exec {stdout}>&1 || return
{
  {
    local -i pipe
    local sig=(EXIT HUP ILL INT PIPE QUIT TERM ZERR)
    local trap=(trap "trap - $sig; kill -- -$sysparams[pid]" $sig)

    exec {pipe}>&1 1>&$stdout || return
    $trap

    {
      $trap
      while command sleep 1 && print -u $pipe .; do; done
    } 2>/dev/null &
    local -i watchdog=$!

    {
      trap - ZERR
      exec {pipe}>&- || return
      () { "$@" } "$@"
    } &
    local -i ret
    wait $! || ret=$?

    trap "exit $ret" TERM
    kill $watchdog || return
    wait $watchdog || return
    return ret
  } | while read; do; done || return
} always {
  exec {stdout}>&-
}