From d9e07b50827cf4051c6f3ddcd4402f6c429569c2 Mon Sep 17 00:00:00 2001
From: Daniel Shahaf <d.s@daniel.shahaf.name>
Date: Fri, 10 Jun 2016 14:25:00 +0000
Subject: [PATCH] 'main': simple parameter expansions at command word: Don't
 use an undefined value.

Causes such expansions to be highlighted as [unknown-token] rather than as default (absent from $region_highlight).

Fixes #337.
---
 highlighters/main/main-highlighter.zsh | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/highlighters/main/main-highlighter.zsh b/highlighters/main/main-highlighter.zsh
index 5fdb63c..f9c4f0b 100644
--- a/highlighters/main/main-highlighter.zsh
+++ b/highlighters/main/main-highlighter.zsh
@@ -374,7 +374,9 @@ _zsh_highlight_main_highlighter()
         local -a match mbegin mend
         local MATCH; integer MBEGIN MEND
         if [[ $res == none ]] && (( ${+parameters} )) &&
-           [[ ${arg[1]} == \$ ]] && [[ ${arg:1} =~ ^([A-Za-z_][A-Za-z0-9_]*|[0-9]+)$ ]]; then
+           [[ ${arg[1]} == \$ ]] && [[ ${arg:1} =~ ^([A-Za-z_][A-Za-z0-9_]*|[0-9]+)$ ]] &&
+           (( ${+parameters[${MATCH}]} ))
+           then
           _zsh_highlight_main__type ${(P)MATCH}
           res=$REPLY
         fi