-fast-collapse-colors

# -*- mode: sh; sh-indentation: 2; indent-tabs-mode: nil; sh-basic-offset: 2; -*-
# -------------------------------------------------------------------------------------------------
# Copyright (c) 2019 Philippe Troin (F-i-f on GitHub)
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function -fast-collapse-colors {
  emulate -LR zsh
  setopt warncreateglobal typesetsilent

  local -a regelts
  local region eregion i start end st_fg st_bg st_other
  for region in $@
  do
    regelts=(${(s: :)region})
    start=$regelts[1]
    end=$regelts[2]
    st_fg=
    st_bg=
    st_other=
    for eregion in $reply[@] $region
    do
      regelts=(${(s: :)eregion})
      if (( regelts[1] <= start && $regelts[2] >= end ))
      then
	for i in ${(ps:,:)regelts[3]}; do
	  case $i in
	    (fg=*) st_fg=$i ;;
	    (bg=*) st_bg=$i ;;
	    (*)    if [[ $i != none ]]; then st_other=${st_other:+$st_other,}$i; fi ;;
	  esac
	done
      fi
    done
    local style=$st_fg
    style+=${st_bg:+${style:+,}$st_bg}
    style+=${st_other:+${style:+,}$st_other}
    if [[ -z $style ]]; then style=none; fi
    reply+=("$start $end $style")
  done
}