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] 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>