Autoload and emulate zsh

_zsh_highlight_internal

@@ -0,0 +1,135 @@
+# Update ZLE buffer syntax highlighting.
+#
+# Invokes each highlighter that needs updating.
+# This function is supposed to be called whenever the ZLE state changes.
+_zsh_highlight_internal()
+{
+  emulate -L zsh
+  setopt localoptions warncreateglobal nobashrematch
+  local REPLY # don't leak $REPLY into global scope
+
+  # Do not highlight if there are more than 300 chars in the buffer. It's most
+  # likely a pasted command or a huge list of files in that case..
+  [[ -n ${ZSH_HIGHLIGHT_MAXLENGTH:-} ]] && [[ $#BUFFER -gt $ZSH_HIGHLIGHT_MAXLENGTH ]] && return
+
+  # Do not highlight if there are pending inputs (copy/paste).
+  [[ $PENDING -gt 0 ]] && return
+
+  {
+    local cache_place
+    local -a region_highlight_copy
+
+    # Select which highlighters in ZSH_HIGHLIGHT_HIGHLIGHTERS need to be invoked.
+    local highlighter; for highlighter in $ZSH_HIGHLIGHT_HIGHLIGHTERS; do
+
+      # eval cache place for current highlighter and prepare it
+      cache_place="_zsh_highlight__highlighter_${highlighter}_cache"
+      typeset -ga ${cache_place}
+
+      # If highlighter needs to be invoked
+      if ! type "_zsh_highlight_highlighter_${highlighter}_predicate" >&/dev/null; then
+        echo "zsh-syntax-highlighting: warning: disabling the ${(qq)highlighter} highlighter as it has not been loaded" >&2
+        # TODO: use ${(b)} rather than ${(q)} if supported
+        ZSH_HIGHLIGHT_HIGHLIGHTERS=( ${ZSH_HIGHLIGHT_HIGHLIGHTERS:#${highlighter}} )
+      elif "_zsh_highlight_highlighter_${highlighter}_predicate"; then
+
+        # save a copy, and cleanup region_highlight
+        region_highlight_copy=("${region_highlight[@]}")
+        region_highlight=()
+
+        # Execute highlighter and save result
+        {
+          "_zsh_highlight_highlighter_${highlighter}_paint"
+        } always {
+          : ${(AP)cache_place::="${region_highlight[@]}"}
+        }
+
+        # Restore saved region_highlight
+        region_highlight=("${region_highlight_copy[@]}")
+
+      fi
+
+      # Use value form cache if any cached
+      region_highlight+=("${(@P)cache_place}")
+
+    done
+
+    # Re-apply zle_highlight settings
+
+    # region
+    () {
+      (( REGION_ACTIVE )) || return
+      integer min max
+      if (( MARK > CURSOR )) ; then
+        min=$CURSOR max=$MARK
+      else
+        min=$MARK max=$CURSOR
+      fi
+      if (( REGION_ACTIVE == 1 )); then
+        [[ $KEYMAP = vicmd ]] && (( max++ ))
+      elif (( REGION_ACTIVE == 2 )); then
+        local needle=$'\n'
+        # CURSOR and MARK are 0 indexed between letters like region_highlight
+        # Do not include the newline in the highlight
+        (( min = ${BUFFER[(Ib:min:)$needle]} ))
+        (( max = ${BUFFER[(ib:max:)$needle]} - 1 ))
+      fi
+      _zsh_highlight_apply_zle_highlight region standout "$min" "$max"
+    }
+
+    # yank / paste (zsh-5.1.1 and newer)
+    (( $+YANK_ACTIVE )) && (( YANK_ACTIVE )) && _zsh_highlight_apply_zle_highlight paste standout "$YANK_START" "$YANK_END"
+
+    # isearch
+    (( $+ISEARCHMATCH_ACTIVE )) && (( ISEARCHMATCH_ACTIVE )) && _zsh_highlight_apply_zle_highlight isearch underline "$ISEARCHMATCH_START" "$ISEARCHMATCH_END"
+
+    # suffix
+    (( $+SUFFIX_ACTIVE )) && (( SUFFIX_ACTIVE )) && _zsh_highlight_apply_zle_highlight suffix bold "$SUFFIX_START" "$SUFFIX_END"
+
+  } always {
+    typeset -g _ZSH_HIGHLIGHT_PRIOR_BUFFER="$BUFFER"
+    typeset -gi _ZSH_HIGHLIGHT_PRIOR_CURSOR=$CURSOR
+  }
+}
+
+# Apply highlighting based on entries in the zle_highlight array.
+# This function takes four arguments:
+# 1. The exact entry (no patterns) in the zle_highlight array:
+#    region, paste, isearch, or suffix
+# 2. The default highlighting that should be applied if the entry is unset
+# 3. and 4. Two integer values describing the beginning and end of the
+#    range. The order does not matter.
+_zsh_highlight_apply_zle_highlight() {
+  local entry="$1" default="$2"
+  integer first="$3" second="$4"
+
+  # read the relevant entry from zle_highlight
+  #
+  # ### In zsh≥5.0.8 we'd use ${(b)entry}, but we support older zsh's, so we don't
+  # ### add (b).  The only effect is on the failure mode for callers that violate
+  # ### the precondition.
+  local region="${zle_highlight[(r)${entry}:*]-}"
+
+  if [[ -z "$region" ]]; then
+    # entry not specified at all, use default value
+    region=$default
+  else
+    # strip prefix
+    region="${region#${entry}:}"
+
+    # no highlighting when set to the empty string or to 'none'
+    if [[ -z "$region" ]] || [[ "$region" == none ]]; then
+      return
+    fi
+  fi
+
+  integer start end
+  if (( first < second )); then
+    start=$first end=$second
+  else
+    start=$second end=$first
+  fi
+  region_highlight+=("$start $end $region, memo=zsh-syntax-highlighting")
+}
+
+_zsh_highlight_internal "$@"