dotfiles/shells/zsh/lib/syntax-highlighting/highlighters/brackets/brackets-highlighter.zsh

#!/usr/bin/env zsh
# -------------------------------------------------------------------------------------------------
# Copyright (c) 2010-2011 zsh-syntax-highlighting contributors
# All rights reserved.
#
# Redistribution and use in source and binary forms, with or without modification, are permitted
# provided that the following conditions are met:
#
#  * Redistributions of source code must retain the above copyright notice, this list of conditions
#    and the following disclaimer.
#  * Redistributions in binary form must reproduce the above copyright notice, this list of
#    conditions and the following disclaimer in the documentation and/or other materials provided
#    with the distribution.
#  * Neither the name of the zsh-syntax-highlighting contributors nor the names of its contributors
#    may be used to endorse or promote products derived from this software without specific prior
#    written permission.
#
# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR
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# IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
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# -------------------------------------------------------------------------------------------------
# -*- mode: zsh; sh-indentation: 2; indent-tabs-mode: nil; sh-basic-offset: 2; -*-
# vim: ft=zsh sw=2 ts=2 et
# -------------------------------------------------------------------------------------------------


# Define default styles.
: ${ZSH_HIGHLIGHT_STYLES[bracket-error]:=fg=red,bold}
: ${ZSH_HIGHLIGHT_STYLES[bracket-level-1]:=fg=blue,bold}
: ${ZSH_HIGHLIGHT_STYLES[bracket-level-2]:=fg=green,bold}
: ${ZSH_HIGHLIGHT_STYLES[bracket-level-3]:=fg=magenta,bold}
: ${ZSH_HIGHLIGHT_STYLES[bracket-level-4]:=fg=yellow,bold}
: ${ZSH_HIGHLIGHT_STYLES[bracket-level-5]:=fg=cyan,bold}
: ${ZSH_HIGHLIGHT_STYLES[cursor-matchingbracket]:=standout}

# Whether the brackets highlighter should be called or not.
_zsh_highlight_brackets_highlighter_predicate()
{
  _zsh_highlight_cursor_moved || _zsh_highlight_buffer_modified
}

# Brackets highlighting function.
_zsh_highlight_brackets_highlighter()
{
  local level=0 pos
  local -A levelpos lastoflevel matching typepos

  # Find all brackets and remember which one is matching
  for (( pos = 0; $pos < ${#BUFFER}; pos++ )) ; do
    local char=$BUFFER[pos+1]
    case $char in
      ["([{"])
        levelpos[$pos]=$((++level))
        lastoflevel[$level]=$pos
        _zsh_highlight_brackets_highlighter_brackettype $char
        ;;
      [")]}"])
        matching[$lastoflevel[$level]]=$pos
        matching[$pos]=$lastoflevel[$level]
        levelpos[$pos]=$((level--))
        _zsh_highlight_brackets_highlighter_brackettype $char
        ;;
      ['"'\'])
        # Skip everything inside quotes
        local quotetype=$char
        while (( $pos < ${#BUFFER} )) ; do
          (( pos++ ))
          [[ $BUFFER[$pos+1] == $quotetype ]] && break
        done
        ;;
    esac
  done

  # Now highlight all found brackets
  for pos in ${(k)levelpos}; do
    if [[ -n $matching[$pos] ]] && [[ $typepos[$pos] == $typepos[$matching[$pos]] ]]; then
      local bracket_color_size=${#ZSH_HIGHLIGHT_STYLES[(I)bracket-level-*]}
      local bracket_color_level=bracket-level-$(( (levelpos[$pos] - 1) % bracket_color_size + 1 ))
      local style=$ZSH_HIGHLIGHT_STYLES[$bracket_color_level]
      region_highlight+=("$pos $((pos + 1)) $style")
    else
      local style=$ZSH_HIGHLIGHT_STYLES[bracket-error]
      region_highlight+=("$pos $((pos + 1)) $style")
    fi
  done

  # If cursor is on a bracket, then highlight corresponding bracket, if any
  pos=$CURSOR
  if [[ -n $levelpos[$pos] ]] && [[ -n $matching[$pos] ]]; then
    local otherpos=$matching[$pos]
    local style=$ZSH_HIGHLIGHT_STYLES[cursor-matchingbracket]
    region_highlight+=("$otherpos $((otherpos + 1)) $style")
  fi
}

# Helper function to differentiate type 
_zsh_highlight_brackets_highlighter_brackettype()
{
  case $1 in
    ["()"]) typepos[$pos]=round;;
    ["[]"]) typepos[$pos]=bracket;;
    ["{}"]) typepos[$pos]=curly;;
    *) ;;
  esac
}