From 4e02ef614f9fd4930aab031cf8512c8607c0d2e9 Mon Sep 17 00:00:00 2001
From: Kaz Kylheku <kaz@kylheku.com>
Date: Sun, 17 Jan 2010 07:46:04 -0800
Subject: * parser.y (regterm, regclass): Relocate handling of empty [] into
 regterm, via empty derivation.

---
 ChangeLog | 5 +++++
 parser.y  | 6 +++---
 2 files changed, 8 insertions(+), 3 deletions(-)

diff --git a/ChangeLog b/ChangeLog
index e023e2f6..dcdd303b 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,8 @@
+2010-01-17  Kaz Kylheku  <kkylheku@gmail.com>
+
+	* parser.y (regterm, regclass): Relocate handling
+	of empty [] into regterm, via empty derivation.
+
 2010-01-16  Kaz Kylheku  <kkylheku@gmail.com>
 
 	Regex syntactic tweaks: support the [] syntax
diff --git a/parser.y b/parser.y
index a3154201..db3ff2c7 100644
--- a/parser.y
+++ b/parser.y
@@ -469,9 +469,8 @@ regbranch : regterm             { $$ = cons($1, nil); }
           ;
 
 regterm : '[' regclass ']'      { $$ = cons(set_s, $2); }
-        | '[' ']'               { $$ = cons(set_s, nil); }
-        | '[' '^' regclass ']'  { $$ = cons(cset_s, $3); }
-        | '[' '^' ']'           { $$ = wild_s; }
+        | '[' '^' regclass ']'  { $$ = if3(nullp($3), wild_s,
+                                                      cons(cset_s, $3)); }
         | '.'                   { $$ = wild_s; }
         | '^'                   { $$ = chr('^'); }
         | ']'                   { $$ = chr(']'); }
@@ -492,6 +491,7 @@ regterm : '[' regclass ']'      { $$ = cons(set_s, $2); }
 
 regclass : regclassterm                 { $$ = cons($1, nil); }
          | regclassterm regclass        { $$ = cons($1, $2); }
+         | /* empty */                  { $$ = nil; }
          ;
 
 regclassterm : regrange         { $$ = $1; }
-- 
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