From d68a78c4a62c12552ca99aff83d5182ea1e0f23f Mon Sep 17 00:00:00 2001
From: Chris Double <chris.double@double.co.nz>
Date: Wed, 28 Nov 2007 15:32:04 +1300
Subject: [PATCH] fix grouping of repeat0 in ebnf

---
 extra/peg/ebnf/ebnf-tests.factor | 20 ++++++++++++++++++++
 extra/peg/ebnf/ebnf.factor       | 18 ++++++++----------
 2 files changed, 28 insertions(+), 10 deletions(-)

diff --git a/extra/peg/ebnf/ebnf-tests.factor b/extra/peg/ebnf/ebnf-tests.factor
index 13d0ce887e..a19bc0188c 100644
--- a/extra/peg/ebnf/ebnf-tests.factor
+++ b/extra/peg/ebnf/ebnf-tests.factor
@@ -64,4 +64,24 @@ IN: temporary
   } 
 } [
   "one (two | three)" 'choice' parse parse-result-ast
+] unit-test
+
+{
+  T{ ebnf-sequence f
+     V{ 
+       T{ ebnf-non-terminal f "one" }
+       T{ ebnf-repeat0 f
+          T{ ebnf-sequence f
+             V{
+                T{ ebnf-choice f
+                   V{ T{ ebnf-non-terminal f "two" } T{ ebnf-non-terminal f "three" } }
+                }
+                T{ ebnf-non-terminal f "four" }
+             }
+          }
+        }
+     }
+  } 
+} [
+  "one {(two | three) four}" 'choice' parse parse-result-ast
 ] unit-test
\ No newline at end of file
diff --git a/extra/peg/ebnf/ebnf.factor b/extra/peg/ebnf/ebnf.factor
index 4a1d7b341b..352390c5cc 100644
--- a/extra/peg/ebnf/ebnf.factor
+++ b/extra/peg/ebnf/ebnf.factor
@@ -103,8 +103,14 @@ DEFER: 'choice'
   ")" token sp hide 
   3array seq [ first ] action ;
 
+: 'repeat0' ( -- parser )
+  "{" token sp hide
+  [ 'choice' sp ] delay
+  "}" token sp hide 
+  3array seq [ first <ebnf-repeat0> ] action ;
+
 : 'sequence' ( -- parser )
-  'element' sp 'group' sp 2array choice 
+  'element' sp 'group' sp 'repeat0' sp 3array choice 
    repeat1 [ 
      dup length 1 = [ first ] [ <ebnf-sequence> ] if
    ] action ;  
@@ -114,21 +120,13 @@ DEFER: 'choice'
     dup length 1 = [ first ] [ <ebnf-choice> ] if
    ] action ;
   
-: 'repeat0' ( -- parser )
-  "{" token sp hide
-  [ 'rhs' sp ] delay
-  "}" token sp hide 
-  3array seq [ first <ebnf-repeat0> ] action ;
-
 : 'action' ( -- parser )
   "=>" token hide
   [ blank? ] satisfy ensure-not [ drop t ] satisfy 2array seq [ first ] action repeat1 [ >string ] action sp
   2array seq [ first <ebnf-action> ] action ;
 
 : 'rhs' ( -- parser )
-  'repeat0'
-  'choice'
-  2array choice 'action' sp optional 2array seq ;
+  'choice' 'action' sp optional 2array seq ;
  
 : 'rule' ( -- parser )
   'non-terminal' [ ebnf-non-terminal-symbol ] action