From 4b37c9098ef8be2b9471d80d889af7bbe1d61d81 Mon Sep 17 00:00:00 2001
From: Chris Double <chris@bethia.(none)>
Date: Wed, 19 Mar 2008 16:54:42 +1300
Subject: [PATCH 01/14] Use multiline for parsing EBNF string

---
 extra/peg/ebnf/ebnf.factor | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/extra/peg/ebnf/ebnf.factor b/extra/peg/ebnf/ebnf.factor
index 5d7d7297ef..4563783ab0 100644
--- a/extra/peg/ebnf/ebnf.factor
+++ b/extra/peg/ebnf/ebnf.factor
@@ -2,7 +2,7 @@
 ! See http://factorcode.org/license.txt for BSD license.
 USING: kernel parser words arrays strings math.parser sequences 
        quotations vectors namespaces math assocs continuations peg
-       peg.parsers unicode.categories ;
+       peg.parsers unicode.categories multiline ;
 IN: peg.ebnf
 
 TUPLE: ebnf-non-terminal symbol ;
@@ -182,4 +182,4 @@ DEFER: 'choice'
     f
    ] if* ;
 
-: <EBNF "EBNF>" parse-tokens " " join ebnf>quot call ; parsing
+: <EBNF "EBNF>" parse-multiline-string ebnf>quot call ; parsing

From cc9a17b551980b43b016bdc7154bcf7c65d12ccf Mon Sep 17 00:00:00 2001
From: Chris Double <chris@bethia.(none)>
Date: Wed, 19 Mar 2008 17:00:53 +1300
Subject: [PATCH 02/14] Use choice* and seq* in ebnf

---
 extra/peg/ebnf/ebnf.factor | 70 ++++++++++++++++++++++++--------------
 1 file changed, 45 insertions(+), 25 deletions(-)

diff --git a/extra/peg/ebnf/ebnf.factor b/extra/peg/ebnf/ebnf.factor
index 4563783ab0..81fc215bd9 100644
--- a/extra/peg/ebnf/ebnf.factor
+++ b/extra/peg/ebnf/ebnf.factor
@@ -100,33 +100,46 @@ M: ebnf (generate-parser) ( ast -- id )
 DEFER: 'rhs'
 
 : 'non-terminal' ( -- parser )
-  CHAR: a CHAR: z range "-" token [ first ] action  2array choice repeat1 [ >string <ebnf-non-terminal> ] action ;
+  [ 
+    CHAR: a CHAR: z range ,
+    "-" token [ first ] action ,
+  ] choice* repeat1 [ >string <ebnf-non-terminal> ] action ;
 
 : 'terminal' ( -- parser )
-  "'" token hide [ CHAR: ' = not ] satisfy repeat1 "'" token hide 3array seq [ first >string <ebnf-terminal> ] action ;
+  [
+    "'" token hide ,
+    [ CHAR: ' = not ] satisfy repeat1 ,
+    "'" token hide ,
+  ] seq* [ first >string <ebnf-terminal> ] action ;
 
 : 'element' ( -- parser )
-  'non-terminal' 'terminal' 2array choice ;
+  [ 
+    'non-terminal' ,
+    'terminal' ,
+  ] choice* ;
 
 DEFER: 'choice'
 
 : 'group' ( -- parser )
-  "(" token sp hide
-  [ 'choice' sp ] delay
-  ")" token sp hide 
-  3array seq [ first ] action ;
+  [
+    "(" token sp hide ,
+    [ 'choice' sp ] delay ,
+    ")" token sp hide  ,
+  ] seq* [ first ] action ;
 
 : 'repeat0' ( -- parser )
-  "{" token sp hide
-  [ 'choice' sp ] delay
-  "}" token sp hide 
-  3array seq [ first <ebnf-repeat0> ] action ;
+  [
+    "{" token sp hide ,
+    [ 'choice' sp ] delay ,
+    "}" token sp hide  ,
+  ] seq* [ first <ebnf-repeat0> ] action ;
 
 : 'optional' ( -- parser )
-  "[" token sp hide
-  [ 'choice' sp ] delay
-  "]" token sp hide 
-  3array seq [ first <ebnf-optional> ] action ;
+  [
+    "[" token sp hide ,
+    [ 'choice' sp ] delay ,
+    "]" token sp hide  ,
+  ] seq* [ first <ebnf-optional> ] action ;
 
 : 'sequence' ( -- parser )
   [ 
@@ -134,8 +147,7 @@ DEFER: 'choice'
     'group' sp , 
     'repeat0' sp ,
     'optional' sp , 
-   ] { } make  choice  
-   repeat1 [ 
+   ] choice* repeat1 [ 
      dup length 1 = [ first ] [ <ebnf-sequence> ] if
    ] action ;  
 
@@ -145,18 +157,26 @@ DEFER: 'choice'
    ] 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 ;
+  [
+    "=>" token hide ,
+    [
+      [ blank? ] satisfy ensure-not ,
+      [ drop t ] satisfy ,
+    ] seq* [ first ] action repeat1 [ >string ] action sp ,
+  ] seq* [ first <ebnf-action> ] action ;
   
 : 'rhs' ( -- parser )
-  'choice' 'action' sp optional 2array seq ;
+  [
+    'choice' ,
+    'action' sp optional ,
+  ] seq* ;
  
 : 'rule' ( -- parser )
-  'non-terminal' [ ebnf-non-terminal-symbol ] action 
-  "=" token sp hide 
-  'rhs' 
-  3array seq [ first2 <ebnf-rule> ] action ;
+  [
+    'non-terminal' [ ebnf-non-terminal-symbol ] action  ,
+    "=" token sp hide  ,
+    'rhs'  ,
+  ] seq* [ first2 <ebnf-rule> ] action ;
 
 : 'ebnf' ( -- parser )
   'rule' sp "." token sp hide list-of [ <ebnf> ] action ;

From 757853812271dbeb31c97f5d33d2f4bf14f9f55f Mon Sep 17 00:00:00 2001
From: Chris Double <chris@bethia.(none)>
Date: Wed, 19 Mar 2008 17:34:28 +1300
Subject: [PATCH 03/14] Minor tidyup of ebnf

---
 extra/peg/ebnf/ebnf-tests.factor | 17 +++++++++++++
 extra/peg/ebnf/ebnf.factor       | 42 ++++++++++++++++++++++++--------
 2 files changed, 49 insertions(+), 10 deletions(-)

diff --git a/extra/peg/ebnf/ebnf-tests.factor b/extra/peg/ebnf/ebnf-tests.factor
index 452da8df05..156f8e9389 100644
--- a/extra/peg/ebnf/ebnf-tests.factor
+++ b/extra/peg/ebnf/ebnf-tests.factor
@@ -97,3 +97,20 @@ IN: peg.ebnf.tests
 } [
   "one [ two ] three" 'choice' parse parse-result-ast
 ] unit-test
+
+{ "foo" } [
+  "\"foo\"" 'identifier' parse parse-result-ast
+] unit-test
+
+{ "foo" } [
+  "'foo'" 'identifier' parse parse-result-ast
+] unit-test
+
+{ "foo" } [
+  "foo" 'non-terminal' parse parse-result-ast ebnf-non-terminal-symbol
+] unit-test
+
+{ "foo" } [
+  "foo]" 'non-terminal' parse parse-result-ast ebnf-non-terminal-symbol
+] unit-test
+
diff --git a/extra/peg/ebnf/ebnf.factor b/extra/peg/ebnf/ebnf.factor
index 81fc215bd9..9a3b70fa1c 100644
--- a/extra/peg/ebnf/ebnf.factor
+++ b/extra/peg/ebnf/ebnf.factor
@@ -2,7 +2,7 @@
 ! See http://factorcode.org/license.txt for BSD license.
 USING: kernel parser words arrays strings math.parser sequences 
        quotations vectors namespaces math assocs continuations peg
-       peg.parsers unicode.categories multiline ;
+       peg.parsers unicode.categories multiline combinators.lib ;
 IN: peg.ebnf
 
 TUPLE: ebnf-non-terminal symbol ;
@@ -99,18 +99,40 @@ M: ebnf (generate-parser) ( ast -- id )
 
 DEFER: 'rhs'
 
+: 'identifier' ( -- parser )
+  #! Return a parser that parses an identifer delimited by
+  #! a quotation character. The quotation can be single
+  #! or double quotes. The AST produced is the identifier
+  #! between the quotes.
+  [
+    [ CHAR: " = not ] satisfy repeat1 "\"" "\"" surrounded-by ,
+    [ CHAR: ' = not ] satisfy repeat1 "'" "'" surrounded-by ,
+  ] choice* [ >string ] action ;
+  
 : 'non-terminal' ( -- parser )
-  [ 
-    CHAR: a CHAR: z range ,
-    "-" token [ first ] action ,
-  ] choice* repeat1 [ >string <ebnf-non-terminal> ] action ;
+  #! A non-terminal is the name of another rule. It can
+  #! be any non-blank character except for characters used
+  #! in the EBNF syntax itself.
+  [
+    {
+      [ dup blank?    ]
+      [ dup CHAR: " = ]
+      [ dup CHAR: ' = ]
+      [ dup CHAR: | = ]
+      [ dup CHAR: { = ]
+      [ dup CHAR: } = ]
+      [ dup CHAR: = = ]
+      [ dup CHAR: ) = ]
+      [ dup CHAR: ( = ]
+      [ dup CHAR: ] = ]
+      [ dup CHAR: [ = ]
+    } || not nip    
+  ] satisfy repeat1 [ >string <ebnf-non-terminal> ] action ;
 
 : 'terminal' ( -- parser )
-  [
-    "'" token hide ,
-    [ CHAR: ' = not ] satisfy repeat1 ,
-    "'" token hide ,
-  ] seq* [ first >string <ebnf-terminal> ] action ;
+  #! A terminal is an identifier enclosed in quotations
+  #! and it represents the literal value of the identifier.
+  'identifier' [ <ebnf-terminal> ] action ;
 
 : 'element' ( -- parser )
   [ 

From 708d55fb8ef4777cb3464b498d794d04a7f96a3a Mon Sep 17 00:00:00 2001
From: Chris Double <chris@bethia.(none)>
Date: Wed, 19 Mar 2008 17:37:08 +1300
Subject: [PATCH 04/14] Add syntax word for ebnf

---
 extra/peg/ebnf/ebnf.factor | 21 +++++++++++++--------
 1 file changed, 13 insertions(+), 8 deletions(-)

diff --git a/extra/peg/ebnf/ebnf.factor b/extra/peg/ebnf/ebnf.factor
index 9a3b70fa1c..e2977a28fb 100644
--- a/extra/peg/ebnf/ebnf.factor
+++ b/extra/peg/ebnf/ebnf.factor
@@ -99,6 +99,11 @@ M: ebnf (generate-parser) ( ast -- id )
 
 DEFER: 'rhs'
 
+: syntax ( string -- parser )
+  #! Parses the string, ignoring white space, and
+  #! does not put the result in the AST.
+  token sp hide ;
+
 : 'identifier' ( -- parser )
   #! Return a parser that parses an identifer delimited by
   #! a quotation character. The quotation can be single
@@ -144,23 +149,23 @@ DEFER: 'choice'
 
 : 'group' ( -- parser )
   [
-    "(" token sp hide ,
+    "(" syntax ,
     [ 'choice' sp ] delay ,
-    ")" token sp hide  ,
+    ")" syntax  ,
   ] seq* [ first ] action ;
 
 : 'repeat0' ( -- parser )
   [
-    "{" token sp hide ,
+    "{" syntax ,
     [ 'choice' sp ] delay ,
-    "}" token sp hide  ,
+    "}" syntax  ,
   ] seq* [ first <ebnf-repeat0> ] action ;
 
 : 'optional' ( -- parser )
   [
-    "[" token sp hide ,
+    "[" syntax ,
     [ 'choice' sp ] delay ,
-    "]" token sp hide  ,
+    "]" syntax  ,
   ] seq* [ first <ebnf-optional> ] action ;
 
 : 'sequence' ( -- parser )
@@ -196,12 +201,12 @@ DEFER: 'choice'
 : 'rule' ( -- parser )
   [
     'non-terminal' [ ebnf-non-terminal-symbol ] action  ,
-    "=" token sp hide  ,
+    "=" syntax  ,
     'rhs'  ,
   ] seq* [ first2 <ebnf-rule> ] action ;
 
 : 'ebnf' ( -- parser )
-  'rule' sp "." token sp hide list-of [ <ebnf> ] action ;
+  'rule' sp "." syntax list-of [ <ebnf> ] action ;
 
 : ebnf>quot ( string -- quot )
   'ebnf' parse [

From 9403d97e22c1e0e59ce4285b033b4db5e4f18b2b Mon Sep 17 00:00:00 2001
From: Chris Double <chris@bethia.(none)>
Date: Wed, 19 Mar 2008 17:52:22 +1300
Subject: [PATCH 05/14] Add syntax-pack and grouped to ebnf refactoring

---
 extra/peg/ebnf/ebnf.factor | 35 +++++++++++++++++------------------
 1 file changed, 17 insertions(+), 18 deletions(-)

diff --git a/extra/peg/ebnf/ebnf.factor b/extra/peg/ebnf/ebnf.factor
index e2977a28fb..fce7a8d3bd 100644
--- a/extra/peg/ebnf/ebnf.factor
+++ b/extra/peg/ebnf/ebnf.factor
@@ -104,6 +104,11 @@ DEFER: 'rhs'
   #! does not put the result in the AST.
   token sp hide ;
 
+: syntax-pack ( begin parser end -- parser )
+  #! Parse 'parser' surrounded by syntax elements
+  #! begin and end.
+  [ syntax ] dipd syntax pack ;
+
 : 'identifier' ( -- parser )
   #! Return a parser that parses an identifer delimited by
   #! a quotation character. The quotation can be single
@@ -147,26 +152,20 @@ DEFER: 'rhs'
 
 DEFER: 'choice'
 
+: grouped ( begin quot end -- parser )
+  #! Parse a group of choices, where the delimiter for the
+  #! group is specified by 'begin' and 'end'. The quotation
+  #! should produce the AST to be the result of the parser.
+  [ [ 'choice' sp ] delay swap action ] dip syntax-pack ;
+
 : 'group' ( -- parser )
-  [
-    "(" syntax ,
-    [ 'choice' sp ] delay ,
-    ")" syntax  ,
-  ] seq* [ first ] action ;
+  "(" [ ] ")" grouped ;
 
 : 'repeat0' ( -- parser )
-  [
-    "{" syntax ,
-    [ 'choice' sp ] delay ,
-    "}" syntax  ,
-  ] seq* [ first <ebnf-repeat0> ] action ;
+  "{" [ <ebnf-repeat0> ] "}" grouped ;
 
 : 'optional' ( -- parser )
-  [
-    "[" syntax ,
-    [ 'choice' sp ] delay ,
-    "]" syntax  ,
-  ] seq* [ first <ebnf-optional> ] action ;
+  "[" [ <ebnf-optional> ] "]" grouped ;
 
 : 'sequence' ( -- parser )
   [ 
@@ -174,14 +173,14 @@ DEFER: 'choice'
     'group' sp , 
     'repeat0' sp ,
     'optional' sp , 
-   ] choice* repeat1 [ 
+  ] choice* repeat1 [ 
      dup length 1 = [ first ] [ <ebnf-sequence> ] if
-   ] action ;  
+  ] action ;  
 
 : 'choice' ( -- parser )
   'sequence' sp "|" token sp list-of [ 
     dup length 1 = [ first ] [ <ebnf-choice> ] if
-   ] action ;
+  ] action ;
 
 : 'action' ( -- parser )
   [

From eef6ae782730ba22a779997023c20d71730abcae Mon Sep 17 00:00:00 2001
From: Chris Double <chris@bethia.(none)>
Date: Wed, 19 Mar 2008 18:07:25 +1300
Subject: [PATCH 06/14] Remove need for '.' to terminate rule lines in EBNF

---
 extra/peg/ebnf/ebnf.factor | 19 ++++++++++++++-----
 1 file changed, 14 insertions(+), 5 deletions(-)

diff --git a/extra/peg/ebnf/ebnf.factor b/extra/peg/ebnf/ebnf.factor
index fce7a8d3bd..e95fc4f9d4 100644
--- a/extra/peg/ebnf/ebnf.factor
+++ b/extra/peg/ebnf/ebnf.factor
@@ -145,10 +145,17 @@ DEFER: 'rhs'
   'identifier' [ <ebnf-terminal> ] action ;
 
 : 'element' ( -- parser )
-  [ 
-    'non-terminal' ,
-    'terminal' ,
-  ] choice* ;
+  #! An element of a rule. It can be a terminal or a 
+  #! non-terminal but must not be followed by a "=". 
+  #! The latter indicates that it is the beginning of a
+  #! new rule.
+  [
+    [ 
+      'non-terminal' ,
+      'terminal' ,
+    ] choice* ,
+    "=" syntax ensure-not ,
+  ] seq* [ first ] action ;
 
 DEFER: 'choice'
 
@@ -168,6 +175,8 @@ DEFER: 'choice'
   "[" [ <ebnf-optional> ] "]" grouped ;
 
 : 'sequence' ( -- parser )
+  #! A sequence of terminals and non-terminals, including
+  #! groupings of those. 
   [ 
     'element' sp ,
     'group' sp , 
@@ -205,7 +214,7 @@ DEFER: 'choice'
   ] seq* [ first2 <ebnf-rule> ] action ;
 
 : 'ebnf' ( -- parser )
-  'rule' sp "." syntax list-of [ <ebnf> ] action ;
+  'rule' sp repeat1 [ <ebnf> ] action ;
 
 : ebnf>quot ( string -- quot )
   'ebnf' parse [

From 208c88c44949f72f62d9cd6ffbf700d301232963 Mon Sep 17 00:00:00 2001
From: Chris Double <chris@bethia.(none)>
Date: Wed, 19 Mar 2008 18:35:45 +1300
Subject: [PATCH 07/14] Update pl0 for ebnf changes, and add more tests

---
 extra/peg/pl0/pl0-tests.factor | 88 +++++++++++++++++++++++++++++++++-
 extra/peg/pl0/pl0.factor       | 35 +++++++-------
 2 files changed, 105 insertions(+), 18 deletions(-)

diff --git a/extra/peg/pl0/pl0-tests.factor b/extra/peg/pl0/pl0-tests.factor
index fa8ac89f57..bf321d54e9 100644
--- a/extra/peg/pl0/pl0-tests.factor
+++ b/extra/peg/pl0/pl0-tests.factor
@@ -1,7 +1,7 @@
 ! Copyright (C) 2007 Chris Double.
 ! See http://factorcode.org/license.txt for BSD license.
 !
-USING: kernel tools.test peg peg.pl0 ;
+USING: kernel tools.test peg peg.pl0 multiline sequences ;
 IN: peg.pl0.tests
 
 { "abc" } [
@@ -11,3 +11,89 @@ IN: peg.pl0.tests
 { 55 } [
   "55abc" number parse parse-result-ast 
 ] unit-test
+
+{ t } [
+  <"
+VAR x, squ;
+
+PROCEDURE square;
+BEGIN
+   squ := x * x
+END;
+
+BEGIN
+   x := 1;
+   WHILE x <= 10 DO
+   BEGIN
+      CALL square;
+      x := x + 1;
+   END
+END.
+"> program parse parse-result-remaining empty?
+] unit-test
+
+{ f } [
+  <"
+CONST
+  m =  7,
+  n = 85;
+
+VAR
+  x, y, z, q, r;
+
+PROCEDURE multiply;
+VAR a, b;
+
+BEGIN
+  a := x;
+  b := y;
+  z := 0;
+  WHILE b > 0 DO BEGIN
+    IF ODD b THEN z := z + a;
+    a := 2 * a;
+    b := b / 2;
+  END
+END;
+
+PROCEDURE divide;
+VAR w;
+BEGIN
+  r := x;
+  q := 0;
+  w := y;
+  WHILE w <= r DO w := 2 * w;
+  WHILE w > y DO BEGIN
+    q := 2 * q;
+    w := w / 2;
+    IF w <= r THEN BEGIN
+      r := r - w;
+      q := q + 1
+    END
+  END
+END;
+
+PROCEDURE gcd;
+VAR f, g;
+BEGIN
+  f := x;
+  g := y;
+  WHILE f # g DO BEGIN
+    IF f < g THEN g := g - f;
+    IF g < f THEN f := f - g;
+  END;
+  z := f
+END;
+
+BEGIN
+  x := m;
+  y := n;
+  CALL multiply;
+  x := 25;
+  y :=  3;
+  CALL divide;
+  x := 84;
+  y := 36;
+  CALL gcd;
+END.
+  "> program parse parse-result-remaining empty?
+] unit-test
\ No newline at end of file
diff --git a/extra/peg/pl0/pl0.factor b/extra/peg/pl0/pl0.factor
index 6844eb44dc..1ef7a23b41 100644
--- a/extra/peg/pl0/pl0.factor
+++ b/extra/peg/pl0/pl0.factor
@@ -1,30 +1,31 @@
 ! Copyright (C) 2007 Chris Double.
 ! See http://factorcode.org/license.txt for BSD license.
 USING: kernel arrays strings math.parser sequences
-peg peg.ebnf peg.parsers memoize ;
+peg peg.ebnf peg.parsers memoize namespaces ;
 IN: peg.pl0
 
 #! Grammar for PL/0 based on http://en.wikipedia.org/wiki/PL/0
 MEMO: ident ( -- parser )
-  CHAR: a CHAR: z range 
-  CHAR: A CHAR: Z range 2array choice repeat1 
-  [ >string ] action ;
+  [
+    CHAR: a CHAR: z range ,
+    CHAR: A CHAR: Z range ,
+  ] choice* repeat1 [ >string ] action ;
 
 MEMO: number ( -- parser )
   CHAR: 0 CHAR: 9 range repeat1 [ string>number ] action ;
 
 <EBNF
-program = block '.' .
-block = [ 'const' ident '=' number { ',' ident '=' number } ';' ]
-        [ 'var' ident { ',' ident } ';' ]
-        { 'procedure' ident ';' [ block ';' ] } statement .
-statement = [ ident ':=' expression | 'call' ident |
-              'begin' statement {';' statement } 'end' |
-              'if' condition 'then' statement |
-              'while' condition 'do' statement ] .
-condition = 'odd' expression |
-            expression ('=' | '#' | '<=' | '<' | '>=' | '>') expression .
-expression = ['+' | '-'] term {('+' | '-') term } .
-term = factor {('*' | '/') factor } .
-factor = ident | number | '(' expression ')'
+program = block "." 
+block = [ "CONST" ident "=" number { "," ident "=" number } ";" ]
+        [ "VAR" ident { "," ident } ";" ]
+        { "PROCEDURE" ident ";" [ block ";" ] } statement 
+statement = [ ident ":=" expression | "CALL" ident |
+              "BEGIN" statement {";" statement } "END" |
+              "IF" condition "THEN" statement |
+              "WHILE" condition "DO" statement ] 
+condition = "ODD" expression |
+            expression ("=" | "#" | "<=" | "<" | ">=" | ">") expression 
+expression = ["+" | "-"] term {("+" | "-") term } 
+term = factor {("*" | "/") factor } 
+factor = ident | number | "(" expression ")"
 EBNF>

From 64135b73e1b029c49af511a9d32307b5c473b52a Mon Sep 17 00:00:00 2001
From: Chris Double <chris@bethia.(none)>
Date: Wed, 19 Mar 2008 19:15:52 +1300
Subject: [PATCH 08/14] Add support for ensure-not and parsing any single
 character to EBNF This allows, for example:   foo = {!("_" | "-") .}

This will match zero or more of any character, except for _ or -
---
 extra/peg/ebnf/ebnf-tests.factor |  1 +
 extra/peg/ebnf/ebnf.factor       | 27 +++++++++++++++++++++++++++
 2 files changed, 28 insertions(+)

diff --git a/extra/peg/ebnf/ebnf-tests.factor b/extra/peg/ebnf/ebnf-tests.factor
index 156f8e9389..86a7a454ed 100644
--- a/extra/peg/ebnf/ebnf-tests.factor
+++ b/extra/peg/ebnf/ebnf-tests.factor
@@ -114,3 +114,4 @@ IN: peg.ebnf.tests
   "foo]" 'non-terminal' parse parse-result-ast ebnf-non-terminal-symbol
 ] unit-test
 
+
diff --git a/extra/peg/ebnf/ebnf.factor b/extra/peg/ebnf/ebnf.factor
index e95fc4f9d4..4dc096ecbd 100644
--- a/extra/peg/ebnf/ebnf.factor
+++ b/extra/peg/ebnf/ebnf.factor
@@ -7,6 +7,8 @@ IN: peg.ebnf
 
 TUPLE: ebnf-non-terminal symbol ;
 TUPLE: ebnf-terminal symbol ;
+TUPLE: ebnf-any-character ;
+TUPLE: ebnf-ensure-not group ;
 TUPLE: ebnf-choice options ;
 TUPLE: ebnf-sequence elements ;
 TUPLE: ebnf-repeat0 group ;
@@ -17,6 +19,8 @@ TUPLE: ebnf rules ;
 
 C: <ebnf-non-terminal> ebnf-non-terminal
 C: <ebnf-terminal> ebnf-terminal
+C: <ebnf-any-character> ebnf-any-character
+C: <ebnf-ensure-not> ebnf-ensure-not
 C: <ebnf-choice> ebnf-choice
 C: <ebnf-sequence> ebnf-sequence
 C: <ebnf-repeat0> ebnf-repeat0
@@ -61,6 +65,9 @@ M: ebnf-non-terminal (generate-parser) ( ast -- id )
     parsers get , \ nth , [ search ] [ 2drop f ] recover , \ or ,
   ] [ ] make delay sp store-parser ;
 
+M: ebnf-any-character (generate-parser) ( ast -- id )
+  drop [ drop t ] satisfy store-parser ;
+
 M: ebnf-choice (generate-parser) ( ast -- id )
   ebnf-choice-options [
     generate-parser get-parser 
@@ -71,6 +78,9 @@ M: ebnf-sequence (generate-parser) ( ast -- id )
     generate-parser get-parser
   ] map seq store-parser ;
 
+M: ebnf-ensure-not (generate-parser) ( ast -- id )
+  ebnf-ensure-not-group generate-parser get-parser ensure-not store-parser ;
+
 M: ebnf-repeat0 (generate-parser) ( ast -- id )
   ebnf-repeat0-group generate-parser get-parser repeat0 store-parser ;
 
@@ -136,6 +146,8 @@ DEFER: 'rhs'
       [ dup CHAR: ( = ]
       [ dup CHAR: ] = ]
       [ dup CHAR: [ = ]
+      [ dup CHAR: . = ]
+      [ dup CHAR: ! = ]
     } || not nip    
   ] satisfy repeat1 [ >string <ebnf-non-terminal> ] action ;
 
@@ -144,6 +156,10 @@ DEFER: 'rhs'
   #! and it represents the literal value of the identifier.
   'identifier' [ <ebnf-terminal> ] action ;
 
+: 'any-character' ( -- parser )
+  #! A parser to match the symbol for any character match.
+  [ CHAR: . = ] satisfy [ drop <ebnf-any-character> ] action ;
+ 
 : 'element' ( -- parser )
   #! An element of a rule. It can be a terminal or a 
   #! non-terminal but must not be followed by a "=". 
@@ -153,6 +169,7 @@ DEFER: 'rhs'
     [ 
       'non-terminal' ,
       'terminal' ,
+      'any-character' ,
     ] choice* ,
     "=" syntax ensure-not ,
   ] seq* [ first ] action ;
@@ -174,10 +191,20 @@ DEFER: 'choice'
 : 'optional' ( -- parser )
   "[" [ <ebnf-optional> ] "]" grouped ;
 
+: 'ensure-not' ( -- parser )
+  #! Parses the '!' syntax to ensure that 
+  #! something that matches the following elements do
+  #! not exist in the parse stream.
+  [
+    "!" syntax ,
+    'group' sp ,
+  ] seq* [ first <ebnf-ensure-not> ] action ;
+
 : 'sequence' ( -- parser )
   #! A sequence of terminals and non-terminals, including
   #! groupings of those. 
   [ 
+    'ensure-not' sp ,
     'element' sp ,
     'group' sp , 
     'repeat0' sp ,

From 82d54d37769a30663face16e7bbd6c800bee8171 Mon Sep 17 00:00:00 2001
From: Chris Double <chris@bethia.(none)>
Date: Thu, 20 Mar 2008 01:18:09 +1300
Subject: [PATCH 09/14] EBNF syntax change [ ... ] is now ( ... )? { ... } is
 now ( ... )* Added ( ... )+

---
 extra/peg/ebnf/ebnf-tests.factor |  4 ++--
 extra/peg/ebnf/ebnf.factor       | 34 +++++++++++++++++++++++---------
 2 files changed, 27 insertions(+), 11 deletions(-)

diff --git a/extra/peg/ebnf/ebnf-tests.factor b/extra/peg/ebnf/ebnf-tests.factor
index 86a7a454ed..6838bf3eca 100644
--- a/extra/peg/ebnf/ebnf-tests.factor
+++ b/extra/peg/ebnf/ebnf-tests.factor
@@ -83,7 +83,7 @@ IN: peg.ebnf.tests
      }
   } 
 } [
-  "one {(two | three) four}" 'choice' parse parse-result-ast
+  "one ((two | three) four)*" 'choice' parse parse-result-ast
 ] unit-test
 
 {
@@ -95,7 +95,7 @@ IN: peg.ebnf.tests
      }
   } 
 } [
-  "one [ two ] three" 'choice' parse parse-result-ast
+  "one ( two )? three" 'choice' parse parse-result-ast
 ] unit-test
 
 { "foo" } [
diff --git a/extra/peg/ebnf/ebnf.factor b/extra/peg/ebnf/ebnf.factor
index 4dc096ecbd..59695998ce 100644
--- a/extra/peg/ebnf/ebnf.factor
+++ b/extra/peg/ebnf/ebnf.factor
@@ -12,6 +12,7 @@ TUPLE: ebnf-ensure-not group ;
 TUPLE: ebnf-choice options ;
 TUPLE: ebnf-sequence elements ;
 TUPLE: ebnf-repeat0 group ;
+TUPLE: ebnf-repeat1 group ;
 TUPLE: ebnf-optional elements ;
 TUPLE: ebnf-rule symbol elements ;
 TUPLE: ebnf-action word ;
@@ -24,6 +25,7 @@ C: <ebnf-ensure-not> ebnf-ensure-not
 C: <ebnf-choice> ebnf-choice
 C: <ebnf-sequence> ebnf-sequence
 C: <ebnf-repeat0> ebnf-repeat0
+C: <ebnf-repeat1> ebnf-repeat1
 C: <ebnf-optional> ebnf-optional
 C: <ebnf-rule> ebnf-rule
 C: <ebnf-action> ebnf-action
@@ -84,6 +86,9 @@ M: ebnf-ensure-not (generate-parser) ( ast -- id )
 M: ebnf-repeat0 (generate-parser) ( ast -- id )
   ebnf-repeat0-group generate-parser get-parser repeat0 store-parser ;
 
+M: ebnf-repeat1 (generate-parser) ( ast -- id )
+  ebnf-repeat1-group generate-parser get-parser repeat1 store-parser ;
+
 M: ebnf-optional (generate-parser) ( ast -- id )
   ebnf-optional-elements generate-parser get-parser optional store-parser ;
 
@@ -176,20 +181,30 @@ DEFER: 'rhs'
 
 DEFER: 'choice'
 
-: grouped ( begin quot end -- parser )
-  #! Parse a group of choices, where the delimiter for the
-  #! group is specified by 'begin' and 'end'. The quotation
-  #! should produce the AST to be the result of the parser.
-  [ [ 'choice' sp ] delay swap action ] dip syntax-pack ;
-
+: grouped ( quot suffix  -- parser )
+  #! Parse a group of choices, with a suffix indicating
+  #! the type of group (repeat0, repeat1, etc) and
+  #! an quot that is the action that produces the AST.
+  "(" [ 'choice' sp ] delay ")" syntax-pack 
+  swap 2seq  
+  [ first ] rot compose action ;
+  
 : 'group' ( -- parser )
-  "(" [ ] ")" grouped ;
+  #! A grouping with no suffix. Used for precedence.
+  [ ] [
+    "*" token sp ensure-not ,
+    "+" token sp ensure-not ,
+    "?" token sp ensure-not ,
+  ] seq* hide grouped ; 
 
 : 'repeat0' ( -- parser )
-  "{" [ <ebnf-repeat0> ] "}" grouped ;
+  [ <ebnf-repeat0> ] "*" syntax grouped ;
+
+: 'repeat1' ( -- parser )
+  [ <ebnf-repeat1> ] "+" syntax grouped ;
 
 : 'optional' ( -- parser )
-  "[" [ <ebnf-optional> ] "]" grouped ;
+  [ <ebnf-optional> ] "?" syntax grouped ;
 
 : 'ensure-not' ( -- parser )
   #! Parses the '!' syntax to ensure that 
@@ -208,6 +223,7 @@ DEFER: 'choice'
     'element' sp ,
     'group' sp , 
     'repeat0' sp ,
+    'repeat1' sp ,
     'optional' sp , 
   ] choice* repeat1 [ 
      dup length 1 = [ first ] [ <ebnf-sequence> ] if

From c0b7bdf823001f4389e7f13df86d05a16dba0822 Mon Sep 17 00:00:00 2001
From: Chris Double <chris@bethia.(none)>
Date: Thu, 20 Mar 2008 01:25:57 +1300
Subject: [PATCH 10/14] Add *, + and ? to list of non-allowed ebnf identifier
 characteres

---
 extra/peg/ebnf/ebnf.factor | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/extra/peg/ebnf/ebnf.factor b/extra/peg/ebnf/ebnf.factor
index 59695998ce..b500d82e98 100644
--- a/extra/peg/ebnf/ebnf.factor
+++ b/extra/peg/ebnf/ebnf.factor
@@ -153,6 +153,9 @@ DEFER: 'rhs'
       [ dup CHAR: [ = ]
       [ dup CHAR: . = ]
       [ dup CHAR: ! = ]
+      [ dup CHAR: * = ]
+      [ dup CHAR: + = ]
+      [ dup CHAR: ? = ]
     } || not nip    
   ] satisfy repeat1 [ >string <ebnf-non-terminal> ] action ;
 

From 65fabeec11956cf7d2d7ddacd50b33b7d6e10823 Mon Sep 17 00:00:00 2001
From: Chris Double <chris@bethia.(none)>
Date: Thu, 20 Mar 2008 02:16:30 +1300
Subject: [PATCH 11/14] remove => action and replace it with [[ code ]] in EBNF
 Previously the action had to be a factor word and could only appear at the
 end of a rule:

  : aword ( ast -- ast ) drop V{ 1 2 } ;
  <EBNF foo = "a" "b" => aword EBNF>

Now actions can appear anywhere after an element, and can be any factor code between [[ ... ]] delimiters:

  <EBNF foo = "a" "b" [[ drop V{ 1 2 } ]] EBNF>
  <EBNF foo = "a" [[ drop 1 ]] "b" [[ drop 2 ]] EBNF>

Unfortunately since this means the ebnf>quot code uses the equivalent of eval, it no longer compiles nicely since it can't be inferred. The generated parsers however do compile.
---
 extra/peg/ebnf/ebnf-tests.factor | 12 +++++++++++-
 extra/peg/ebnf/ebnf.factor       | 25 ++++++++++++++-----------
 2 files changed, 25 insertions(+), 12 deletions(-)

diff --git a/extra/peg/ebnf/ebnf-tests.factor b/extra/peg/ebnf/ebnf-tests.factor
index 6838bf3eca..63cec2f120 100644
--- a/extra/peg/ebnf/ebnf-tests.factor
+++ b/extra/peg/ebnf/ebnf-tests.factor
@@ -1,7 +1,7 @@
 ! Copyright (C) 2007 Chris Double.
 ! See http://factorcode.org/license.txt for BSD license.
 !
-USING: kernel tools.test peg peg.ebnf ;
+USING: kernel tools.test peg peg.ebnf compiler.units ;
 IN: peg.ebnf.tests
 
 { T{ ebnf-non-terminal f "abc" } } [
@@ -114,4 +114,14 @@ IN: peg.ebnf.tests
   "foo]" 'non-terminal' parse parse-result-ast ebnf-non-terminal-symbol
 ] unit-test
 
+{ V{ "a" "b" } } [
+  "foo='a' 'b'" ebnf>quot with-compilation-unit "ab" foo parse parse-result-ast 
+] unit-test
 
+{ V{ 1 "b" } } [
+  "foo='a' [[ drop 1 ]] 'b'" ebnf>quot with-compilation-unit "ab" foo parse parse-result-ast 
+] unit-test
+
+{ V{ 1 2 } } [
+  "foo='a' [[ drop 1 ]] 'b' [[ drop 2 ]]" ebnf>quot with-compilation-unit "ab" foo 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 b500d82e98..2e0740663a 100644
--- a/extra/peg/ebnf/ebnf.factor
+++ b/extra/peg/ebnf/ebnf.factor
@@ -2,7 +2,8 @@
 ! See http://factorcode.org/license.txt for BSD license.
 USING: kernel parser words arrays strings math.parser sequences 
        quotations vectors namespaces math assocs continuations peg
-       peg.parsers unicode.categories multiline combinators.lib ;
+       peg.parsers unicode.categories multiline combinators.lib 
+       splitting ;
 IN: peg.ebnf
 
 TUPLE: ebnf-non-terminal symbol ;
@@ -15,7 +16,7 @@ TUPLE: ebnf-repeat0 group ;
 TUPLE: ebnf-repeat1 group ;
 TUPLE: ebnf-optional elements ;
 TUPLE: ebnf-rule symbol elements ;
-TUPLE: ebnf-action word ;
+TUPLE: ebnf-action code ;
 TUPLE: ebnf rules ;
 
 C: <ebnf-non-terminal> ebnf-non-terminal
@@ -98,7 +99,7 @@ M: ebnf-rule (generate-parser) ( ast -- id )
   swap [ parsers get set-nth ] keep ;
 
 M: ebnf-action (generate-parser) ( ast -- id )
-  ebnf-action-word search 1quotation 
+  ebnf-action-code string-lines parse-lines  
   last-parser get get-parser swap action store-parser ;
 
 M: vector (generate-parser) ( ast -- id )
@@ -237,20 +238,22 @@ DEFER: 'choice'
     dup length 1 = [ first ] [ <ebnf-choice> ] if
   ] action ;
 
-: 'action' ( -- parser )
+: 'factor-code' ( -- parser )
   [
-    "=>" token hide ,
-    [
-      [ blank? ] satisfy ensure-not ,
-      [ drop t ] satisfy ,
-    ] seq* [ first ] action repeat1 [ >string ] action sp ,
-  ] seq* [ first <ebnf-action> ] action ;
+    "]]" token ensure-not ,
+    [ drop t ] satisfy ,
+  ] seq* [ first ] action repeat0 [ >string ] action ;
+
+: 'action' ( -- parser )
+  "[[" 'factor-code' "]]" syntax-pack [ <ebnf-action> ] action ;
   
 : 'rhs' ( -- parser )
   [
     'choice' ,
     'action' sp optional ,
-  ] seq* ;
+  ] seq* repeat1 [ 
+    dup length 1 = [ first ] [ <ebnf-sequence> ] if
+  ] action ;
  
 : 'rule' ( -- parser )
   [

From 92d8140d87cff4015eb9d396296db0d015d7e0dd Mon Sep 17 00:00:00 2001
From: Chris Double <chris@bethia.(none)>
Date: Thu, 20 Mar 2008 03:05:40 +1300
Subject: [PATCH 12/14] Change ebnf-action to properly nest with attached
 parser This allows removal of last-parser hack. Syntax of EBNF changes
 though. Now an action must attach to a group:

  <EBNF foo = (a b c) [[ ...act on group... ]] EBNF>
---
 extra/peg/ebnf/ebnf-tests.factor | 18 ++++--------
 extra/peg/ebnf/ebnf.factor       | 49 ++++++++++++++------------------
 2 files changed, 27 insertions(+), 40 deletions(-)

diff --git a/extra/peg/ebnf/ebnf-tests.factor b/extra/peg/ebnf/ebnf-tests.factor
index 63cec2f120..8846a9c94c 100644
--- a/extra/peg/ebnf/ebnf-tests.factor
+++ b/extra/peg/ebnf/ebnf-tests.factor
@@ -15,11 +15,8 @@ IN: peg.ebnf.tests
 {
   T{ ebnf-rule f 
      "digit"
-     V{ 
-       T{ ebnf-choice f
-          V{ T{ ebnf-terminal f "1" } T{ ebnf-terminal f "2" } }
-       }
-       f
+     T{ ebnf-choice f
+        V{ T{ ebnf-terminal f "1" } T{ ebnf-terminal f "2" } }
      }
   } 
 } [
@@ -29,11 +26,8 @@ IN: peg.ebnf.tests
 {
   T{ ebnf-rule f 
      "digit" 
-     V{
-       T{ ebnf-sequence f
-          V{ T{ ebnf-terminal f "1" } T{ ebnf-terminal f "2" } }
-       }
-       f
+     T{ ebnf-sequence f
+        V{ T{ ebnf-terminal f "1" } T{ ebnf-terminal f "2" } }
      }
   }   
 } [
@@ -119,9 +113,9 @@ IN: peg.ebnf.tests
 ] unit-test
 
 { V{ 1 "b" } } [
-  "foo='a' [[ drop 1 ]] 'b'" ebnf>quot with-compilation-unit "ab" foo parse parse-result-ast 
+  "foo=('a')[[ drop 1 ]] 'b'" ebnf>quot with-compilation-unit "ab" foo parse parse-result-ast 
 ] unit-test
 
 { V{ 1 2 } } [
-  "foo='a' [[ drop 1 ]] 'b' [[ drop 2 ]]" ebnf>quot with-compilation-unit "ab" foo parse parse-result-ast 
+  "foo=('a') [[ drop 1 ]] ('b') [[ drop 2 ]]" ebnf>quot with-compilation-unit "ab" foo 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 2e0740663a..e2c2dd5006 100644
--- a/extra/peg/ebnf/ebnf.factor
+++ b/extra/peg/ebnf/ebnf.factor
@@ -16,7 +16,7 @@ TUPLE: ebnf-repeat0 group ;
 TUPLE: ebnf-repeat1 group ;
 TUPLE: ebnf-optional elements ;
 TUPLE: ebnf-rule symbol elements ;
-TUPLE: ebnf-action code ;
+TUPLE: ebnf-action parser code ;
 TUPLE: ebnf rules ;
 
 C: <ebnf-non-terminal> ebnf-non-terminal
@@ -34,12 +34,10 @@ C: <ebnf> ebnf
 
 SYMBOL: parsers
 SYMBOL: non-terminals
-SYMBOL: last-parser
 
 : reset-parser-generation ( -- ) 
   V{ } clone parsers set 
-  H{ } clone non-terminals set 
-  f last-parser set ;
+  H{ } clone non-terminals set ;
 
 : store-parser ( parser -- number )
   parsers get [ push ] keep length 1- ;
@@ -57,7 +55,7 @@ SYMBOL: last-parser
 GENERIC: (generate-parser) ( ast -- id )
 
 : generate-parser ( ast -- id )
-  (generate-parser) dup last-parser set ;
+  (generate-parser) ;
 
 M: ebnf-terminal (generate-parser) ( ast -- id )
   ebnf-terminal-symbol token sp store-parser ;
@@ -99,15 +97,12 @@ M: ebnf-rule (generate-parser) ( ast -- id )
   swap [ parsers get set-nth ] keep ;
 
 M: ebnf-action (generate-parser) ( ast -- id )
-  ebnf-action-code string-lines parse-lines  
-  last-parser get get-parser swap action store-parser ;
+  [ ebnf-action-parser generate-parser get-parser ] keep
+  ebnf-action-code string-lines parse-lines action store-parser ;
 
 M: vector (generate-parser) ( ast -- id )
   [ generate-parser ] map peek ;
 
-M: f (generate-parser) ( ast -- id )
-  drop last-parser get ;
-
 M: ebnf (generate-parser) ( ast -- id )
   ebnf-rules [
     generate-parser 
@@ -199,6 +194,7 @@ DEFER: 'choice'
     "*" token sp ensure-not ,
     "+" token sp ensure-not ,
     "?" token sp ensure-not ,
+    "[[" token sp ensure-not ,
   ] seq* hide grouped ; 
 
 : 'repeat0' ( -- parser )
@@ -210,6 +206,19 @@ DEFER: 'choice'
 : 'optional' ( -- parser )
   [ <ebnf-optional> ] "?" syntax grouped ;
 
+: 'factor-code' ( -- parser )
+  [
+    "]]" token ensure-not ,
+    [ drop t ] satisfy ,
+  ] seq* [ first ] action repeat0 [ >string ] action ;
+
+: 'action' ( -- parser )
+  [
+    "(" [ 'choice' sp ] delay ")" syntax-pack ,
+    "[[" 'factor-code' "]]" syntax-pack ,
+  ] seq* [ first2 <ebnf-action> ] action ;
+   
+
 : 'ensure-not' ( -- parser )
   #! Parses the '!' syntax to ensure that 
   #! something that matches the following elements do
@@ -229,6 +238,7 @@ DEFER: 'choice'
     'repeat0' sp ,
     'repeat1' sp ,
     'optional' sp , 
+    'action' sp , 
   ] choice* repeat1 [ 
      dup length 1 = [ first ] [ <ebnf-sequence> ] if
   ] action ;  
@@ -237,29 +247,12 @@ DEFER: 'choice'
   'sequence' sp "|" token sp list-of [ 
     dup length 1 = [ first ] [ <ebnf-choice> ] if
   ] action ;
-
-: 'factor-code' ( -- parser )
-  [
-    "]]" token ensure-not ,
-    [ drop t ] satisfy ,
-  ] seq* [ first ] action repeat0 [ >string ] action ;
-
-: 'action' ( -- parser )
-  "[[" 'factor-code' "]]" syntax-pack [ <ebnf-action> ] action ;
-  
-: 'rhs' ( -- parser )
-  [
-    'choice' ,
-    'action' sp optional ,
-  ] seq* repeat1 [ 
-    dup length 1 = [ first ] [ <ebnf-sequence> ] if
-  ] action ;
  
 : 'rule' ( -- parser )
   [
     'non-terminal' [ ebnf-non-terminal-symbol ] action  ,
     "=" syntax  ,
-    'rhs'  ,
+    'choice'  ,
   ] seq* [ first2 <ebnf-rule> ] action ;
 
 : 'ebnf' ( -- parser )

From 97b58580a7a0bb633d88c1f7855ba3ad7a2cbf03 Mon Sep 17 00:00:00 2001
From: Chris Double <chris@bethia.(none)>
Date: Thu, 20 Mar 2008 03:30:53 +1300
Subject: [PATCH 13/14] Add expression evaluator example for EBNF

---
 extra/peg/expr/authors.txt |  1 +
 extra/peg/expr/expr.factor | 30 ++++++++++++++++++++++++++++++
 extra/peg/expr/summary.txt |  1 +
 extra/peg/expr/tags.txt    |  1 +
 4 files changed, 33 insertions(+)
 create mode 100644 extra/peg/expr/authors.txt
 create mode 100644 extra/peg/expr/expr.factor
 create mode 100644 extra/peg/expr/summary.txt
 create mode 100644 extra/peg/expr/tags.txt

diff --git a/extra/peg/expr/authors.txt b/extra/peg/expr/authors.txt
new file mode 100644
index 0000000000..44b06f94bc
--- /dev/null
+++ b/extra/peg/expr/authors.txt
@@ -0,0 +1 @@
+Chris Double
diff --git a/extra/peg/expr/expr.factor b/extra/peg/expr/expr.factor
new file mode 100644
index 0000000000..ed13ac0e50
--- /dev/null
+++ b/extra/peg/expr/expr.factor
@@ -0,0 +1,30 @@
+! Copyright (C) 2008 Chris Double.
+! See http://factorcode.org/license.txt for BSD license.
+USING: kernel arrays strings math.parser sequences
+peg peg.ebnf peg.parsers memoize math ;
+IN: peg.expr
+
+: operator-fold ( lhs seq -- value )
+ #! Perform a fold of a lhs, followed by a sequence of pairs being
+ #! { operator rhs } in to a tree structure of the correct precedence.
+ swap [ first2 swap call ] reduce ;
+
+<EBNF
+
+times    = ("*") [[ drop [ * ] ]]
+divide   = ("/") [[ drop [ / ] ]]
+add      = ("+") [[ drop [ + ] ]]
+subtract = ("-") [[ drop [ - ] ]]
+
+digit    = "0" | "1" | "2" | "3" | "4" |
+           "5" | "6" | "7" | "8" | "9" 
+number   = ((digit)+) [[ concat string>number ]]
+
+value    = number | ("(" expr ")") [[ second ]] 
+product = (value ((times | divide) value)*) [[ first2 operator-fold ]]
+sum = (product ((add | subtract) product)*) [[ first2 operator-fold ]]
+expr = sum
+EBNF>
+
+: eval-expr ( string -- number )
+  expr parse parse-result-ast ;
\ No newline at end of file
diff --git a/extra/peg/expr/summary.txt b/extra/peg/expr/summary.txt
new file mode 100644
index 0000000000..6c3c140b2b
--- /dev/null
+++ b/extra/peg/expr/summary.txt
@@ -0,0 +1 @@
+Simple expression evaluator using EBNF
diff --git a/extra/peg/expr/tags.txt b/extra/peg/expr/tags.txt
new file mode 100644
index 0000000000..9da56880c0
--- /dev/null
+++ b/extra/peg/expr/tags.txt
@@ -0,0 +1 @@
+parsing

From 005de2515629b53e1c1c823798cfdb0f791d5f67 Mon Sep 17 00:00:00 2001
From: Slava Pestov <slava@oberon.internal.stack-effects.com>
Date: Wed, 19 Mar 2008 14:25:53 -0500
Subject: [PATCH 14/14] Cocoa UI cleanup

---
 extra/cocoa/windows/windows.factor |  3 ++-
 extra/tools/walker/walker.factor   |  4 +---
 extra/ui/cocoa/cocoa.factor        | 35 +++++++++++++++++++-----------
 extra/ui/cocoa/views/views.factor  |  9 +++++++-
 extra/ui/windows/windows.factor    | 16 --------------
 5 files changed, 33 insertions(+), 34 deletions(-)

diff --git a/extra/cocoa/windows/windows.factor b/extra/cocoa/windows/windows.factor
index b45acaf852..74a181f9a2 100755
--- a/extra/cocoa/windows/windows.factor
+++ b/extra/cocoa/windows/windows.factor
@@ -30,7 +30,8 @@ IN: cocoa.windows
 : <ViewWindow> ( view rect -- window )
     <NSWindow> [ swap -> setContentView: ] keep
     dup dup -> contentView -> setInitialFirstResponder:
-    dup 1 -> setAcceptsMouseMovedEvents: ;
+    dup 1 -> setAcceptsMouseMovedEvents:
+    dup 0 -> setReleasedWhenClosed: ;
 
 : window-content-rect ( window -- rect )
     NSWindow over -> frame rot -> styleMask
diff --git a/extra/tools/walker/walker.factor b/extra/tools/walker/walker.factor
index 610d3db0a3..6ef5309214 100755
--- a/extra/tools/walker/walker.factor
+++ b/extra/tools/walker/walker.factor
@@ -30,8 +30,6 @@ DEFER: start-walker-thread
         2dup start-walker-thread
     ] if* ;
 
-USING: io.streams.c prettyprint ;
-
 : show-walker ( -- thread )
     get-walker-thread
     [ show-walker-hook get call ] keep ;
@@ -40,7 +38,7 @@ USING: io.streams.c prettyprint ;
     {
         { [ dup continuation? ] [ (continue) ] }
         { [ dup quotation? ] [ call ] }
-        { [ dup not ] [ "Single stepping abandoned" throw ] }
+        { [ dup not ] [ "Single stepping abandoned" rethrow ] }
     } cond ;
 
 : break ( -- )
diff --git a/extra/ui/cocoa/cocoa.factor b/extra/ui/cocoa/cocoa.factor
index 572e798bd0..79b7041dcb 100755
--- a/extra/ui/cocoa/cocoa.factor
+++ b/extra/ui/cocoa/cocoa.factor
@@ -1,4 +1,4 @@
-! Copyright (C) 2006, 2007 Slava Pestov.
+! Copyright (C) 2006, 2008 Slava Pestov.
 ! See http://factorcode.org/license.txt for BSD license.
 USING: math arrays cocoa cocoa.application command-line
 kernel memory namespaces cocoa.messages cocoa.runtime
@@ -8,6 +8,10 @@ ui.clipboards ui.gadgets ui.gadgets.worlds ui.cocoa.views
 core-foundation threads ;
 IN: ui.cocoa
 
+TUPLE: handle view window ;
+
+C: <handle> handle
+
 TUPLE: cocoa-ui-backend ;
 
 SYMBOL: stop-after-last-window?
@@ -47,27 +51,30 @@ M: pasteboard set-clipboard-contents
         dup rot world>NSRect <ViewWindow>
         dup install-window-delegate
         over -> release
-        2array
+        <handle>
     ] keep set-world-handle ;
 
 M: cocoa-ui-backend set-title ( string world -- )
-    world-handle second swap <NSString> -> setTitle: ;
+    world-handle handle-window swap <NSString> -> setTitle: ;
 
 : enter-fullscreen ( world -- )
-    world-handle first NSScreen -> mainScreen f -> enterFullScreenMode:withOptions: drop ;
+    world-handle handle-view
+    NSScreen -> mainScreen
+    f -> enterFullScreenMode:withOptions:
+    drop ;
 
 : exit-fullscreen ( world -- )
-    world-handle first f -> exitFullScreenModeWithOptions: ;
+    world-handle handle-view f -> exitFullScreenModeWithOptions: ;
 
 M: cocoa-ui-backend set-fullscreen* ( ? world -- )
     swap [ enter-fullscreen ] [ exit-fullscreen ] if ;
 
 M: cocoa-ui-backend fullscreen* ( world -- ? )
-    world-handle first -> isInFullScreenMode zero? not ;
+    world-handle handle-view -> isInFullScreenMode zero? not ;
 
 : auto-position ( world -- )
     dup world-loc { 0 0 } = [
-        world-handle second -> center
+        world-handle handle-window -> center
     ] [
         drop
     ] if ;
@@ -75,27 +82,29 @@ M: cocoa-ui-backend fullscreen* ( world -- ? )
 M: cocoa-ui-backend (open-window) ( world -- )
     dup gadget-window
     dup auto-position
-    world-handle second f -> makeKeyAndOrderFront: ;
+    world-handle handle-window f -> makeKeyAndOrderFront: ;
 
 M: cocoa-ui-backend (close-window) ( handle -- )
-    first unregister-window ;
+    handle-window -> release ;
 
 M: cocoa-ui-backend close-window ( gadget -- )
     find-world [
-        world-handle second f -> performClose:
+        world-handle [
+            handle-window f -> performClose:
+        ] when*
     ] when* ;
 
 M: cocoa-ui-backend raise-window* ( world -- )
     world-handle [
-        second dup f -> orderFront: -> makeKeyWindow
+        handle-window dup f -> orderFront: -> makeKeyWindow
         NSApp 1 -> activateIgnoringOtherApps:
     ] when* ;
 
 M: cocoa-ui-backend select-gl-context ( handle -- )
-    first -> openGLContext -> makeCurrentContext ;
+    handle-view -> openGLContext -> makeCurrentContext ;
 
 M: cocoa-ui-backend flush-gl-context ( handle -- )
-    first -> openGLContext -> flushBuffer ;
+    handle-view -> openGLContext -> flushBuffer ;
 
 SYMBOL: cocoa-init-hook
 
diff --git a/extra/ui/cocoa/views/views.factor b/extra/ui/cocoa/views/views.factor
index a965e8a30c..5b975f40de 100755
--- a/extra/ui/cocoa/views/views.factor
+++ b/extra/ui/cocoa/views/views.factor
@@ -313,6 +313,7 @@ CLASS: {
 { "dealloc" "void" { "id" "SEL" }
     [
         drop
+        dup unregister-window
         dup remove-observer
         SUPER-> dealloc
     ]
@@ -349,7 +350,13 @@ CLASS: {
 
 { "windowShouldClose:" "bool" { "id" "SEL" "id" }
     [
-        2nip -> contentView window ungraft t
+        3drop t
+    ]
+}
+
+{ "windowWillClose:" "void" { "id" "SEL" "id" }
+    [
+        2nip -> object -> contentView window ungraft
     ]
 } ;
 
diff --git a/extra/ui/windows/windows.factor b/extra/ui/windows/windows.factor
index 0c9c23cf76..f47a82275b 100755
--- a/extra/ui/windows/windows.factor
+++ b/extra/ui/windows/windows.factor
@@ -376,22 +376,6 @@ SYMBOL: trace-messages?
 
 : peek-message? ( msg -- ? ) f 0 0 PM_REMOVE PeekMessage zero? ;
 
-! ! ! !
-: set-world-dim ( dim world -- )
-    swap >r world-handle win-hWnd HWND_TOP 20 20 r> first2 0
-    SetWindowPos drop ;
-USE: random
-USE: arrays
-
-: twiddle
-    100 500 random +
-    100 500 random +
-    2array
-    "x" get-global find-world
-    set-world-dim
-    yield ;
-! ! ! !
-
 : event-loop ( msg -- )
     {
         { [ windows get empty? ] [ drop ] }