Highlight backslash escapes within $'' strings.

Correct highlighting of backslash escapes within "" strings: highlight only
the four specific escape sequences defined there.

Fixes zsh-users/zsh-syntax-highlighting#196.

highlighters/main/README.md

@@ -45,6 +45,7 @@ This highlighter defines the following styles:
 * `dollar-quoted-argument` - dollar quoted arguments (`` $'foo' ``)
 * `dollar-double-quoted-argument` -  dollar double quoted arguments ($foo inside "")
 * `back-double-quoted-argument` -  back double quoted arguments (\x inside "")
+* `back-dollar-quoted-argument` -  back dollar quoted arguments (\x inside $'')
 * `assign` - variable assignments
 * `default` - parts of the buffer that do not match anything
 

highlighters/main/main-highlighter.zsh

@@ -54,6 +54,7 @@
 : ${ZSH_HIGHLIGHT_STYLES[dollar-quoted-argument]:=fg=yellow}
 : ${ZSH_HIGHLIGHT_STYLES[dollar-double-quoted-argument]:=fg=cyan}
 : ${ZSH_HIGHLIGHT_STYLES[back-double-quoted-argument]:=fg=cyan}
+: ${ZSH_HIGHLIGHT_STYLES[back-dollar-quoted-argument]:=fg=cyan}
 : ${ZSH_HIGHLIGHT_STYLES[assign]:=none}
 
 # Whether the highlighter should be called or not.
@@ -103,7 +104,7 @@ _zsh_highlight_main_highlighter()
 
   for arg in ${(z)buf}; do
     # substr_color is set to 1 to disable adding an entry to region_highlight
-    # for this iteration.  Currently, that is done for "" strings,
+    # for this iteration.  Currently, that is done for "" and $'' strings,
     # which add the entry early so escape sequences within the string override
     # the string's color.
     integer substr_color=0
@@ -204,6 +205,9 @@ _zsh_highlight_main_highlighter()
                  substr_color=1
                  ;;
         \$\'*)   style=$ZSH_HIGHLIGHT_STYLES[dollar-quoted-argument]
+                 _zsh_highlight_main_add_region_highlight $start_pos $end_pos $style
+                 _zsh_highlight_main_highlighter_highlight_dollar_string
+                 substr_color=1
                  ;;
         '`'*)    style=$ZSH_HIGHLIGHT_STYLES[back-quoted-argument];;
         *[*?]*)  $highlight_glob && style=$ZSH_HIGHLIGHT_STYLES[globbing] || style=$ZSH_HIGHLIGHT_STYLES[default];;
@@ -265,8 +269,6 @@ _zsh_highlight_main_highlighter_highlight_string()
 {
   setopt localoptions noksharrays
   local i j k style
-  local AA
-  integer c
   # Starting quote is at 1, so start parsing at offset 2 in the string.
   for (( i = 2 ; i < end_pos - start_pos ; i += 1 )) ; do
     (( j = i + start_pos - 1 ))
@@ -282,6 +284,33 @@ _zsh_highlight_main_highlighter_highlight_string()
             fi
             ;;
       "\\") style=$ZSH_HIGHLIGHT_STYLES[back-double-quoted-argument]
+            if [[ \\\`\"\$ == *$arg[$i+1]* ]]; then
+              (( k += 1 )) # Color following char too.
+              (( i += 1 )) # Skip parsing the escaped char.
+            else
+              continue
+            fi
+            ;;
+      *) continue ;;
+
+    esac
+    _zsh_highlight_main_add_region_highlight $j $k $style
+  done
+}
+
+# Highlight special chars inside dollar-quoted strings
+_zsh_highlight_main_highlighter_highlight_dollar_string()
+{
+  setopt localoptions noksharrays
+  local i j k style
+  local AA
+  integer c
+  # Starting dollar-quote is at 1:2, so start parsing at offset 3 in the string.
+  for (( i = 3 ; i < end_pos - start_pos ; i += 1 )) ; do
+    (( j = i + start_pos - 1 ))
+    (( k = j + 1 ))
+    case "$arg[$i]" in
+      "\\") style=$ZSH_HIGHLIGHT_STYLES[back-dollar-quoted-argument]
             for (( c = i + 1 ; c < end_pos - start_pos ; c += 1 )); do
               [[ "$arg[$c]" != ([0-9,xX,a-f,A-F]) ]] && break
             done

highlighters/main/test-data/dollar-quoted2.zsh

@@ -0,0 +1,38 @@
+#!/usr/bin/env zsh
+# -------------------------------------------------------------------------------------------------
+# Copyright (c) 2015 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
+# IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
+# FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR
+# CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+# DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER
+# IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
+# OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+# -------------------------------------------------------------------------------------------------
+# -*- mode: zsh; sh-indentation: 2; indent-tabs-mode: nil; sh-basic-offset: 2; -*-
+# vim: ft=zsh sw=2 ts=2 et
+# -------------------------------------------------------------------------------------------------
+
+ZSH_HIGHLIGHT_STYLES[back-dollar-quoted-argument]=$unused_highlight
+BUFFER=": \$'foo\xbar'"
+
+expected_region_highlight=(
+  "3 7 $ZSH_HIGHLIGHT_STYLES[dollar-quoted-argument]" # $'foo
+  "8 11 $ZSH_HIGHLIGHT_STYLES[back-dollar-quoted-argument]" # \xba
+  "12 13 $ZSH_HIGHLIGHT_STYLES[dollar-quoted-argument]" # r'
+)

highlighters/main/test-data/double-quoted.zsh

@@ -29,7 +29,7 @@
 # -------------------------------------------------------------------------------------------------
 
 BUFFER=': "foo$bar:\`:\":\$:'
-BUFFER+=\\\':\"
+BUFFER+=\\\\:\"
 
 expected_region_highlight=(
   "3 6 $ZSH_HIGHLIGHT_STYLES[double-quoted-argument]" # "foo
@@ -41,6 +41,6 @@ expected_region_highlight=(
   "17 17 $ZSH_HIGHLIGHT_STYLES[double-quoted-argument]" # :
   "18 19 $ZSH_HIGHLIGHT_STYLES[back-double-quoted-argument]" # \"
   "20 20 $ZSH_HIGHLIGHT_STYLES[double-quoted-argument]" # :
-  "21 22 $ZSH_HIGHLIGHT_STYLES[back-double-quoted-argument]" # \'
+  "21 22 $ZSH_HIGHLIGHT_STYLES[back-double-quoted-argument]" # \\
   "23 24 $ZSH_HIGHLIGHT_STYLES[double-quoted-argument]" # :"
 )

highlighters/main/test-data/double-quoted3.zsh

@@ -29,10 +29,12 @@
 # -------------------------------------------------------------------------------------------------
 
 BUFFER=': "$" "$42foo"'
+BUFFER+=\ \"\\\'\\x\"
 
 expected_region_highlight=(
   "3 5 $ZSH_HIGHLIGHT_STYLES[double-quoted-argument]" # "$"
   "7 7 $ZSH_HIGHLIGHT_STYLES[double-quoted-argument]" # "
   "8 10 $ZSH_HIGHLIGHT_STYLES[dollar-double-quoted-argument]" # $42
   "11 14 $ZSH_HIGHLIGHT_STYLES[double-quoted-argument]" # foo"
+  "16 21 $ZSH_HIGHLIGHT_STYLES[double-quoted-argument]" # "\'\x" - \' and \x are not escape sequences
 )