added a test suite, adapted from PL/0 Tools

test/T00Output.mod

@@ -0,0 +1,14 @@
+(* http://ooc.sourceforge.net/OOCref/OOCref_7.html#SEC72 *)
+MODULE T00Output;
+IMPORT Out;
+
+BEGIN
+   Out.String( "Hello World" );
+   Out.Ln;
+   Out.Int( -1, 0 );
+   Out.Ln;
+   Out.Int(  0, 0 );
+   Out.Ln;
+   Out.Int(  1, 0 );
+   Out.Ln
+END T00Output.

test/T01Arithmetic.mod

@@ -0,0 +1,18 @@
+MODULE T01Arithmetic;
+IMPORT Out;
+
+BEGIN
+  Out.Int( 2 + 3,   0 ); Out.Ln;
+  Out.Int( 2 - 3,   0 ); Out.Ln;
+  Out.Int( 2 * 3,   0 ); Out.Ln;
+  Out.Int( 2 DIV 3, 0 ); Out.Ln;
+  Out.Int( 2 MOD 3, 0 ); Out.Ln;
+
+  Out.Int( 3 + 2,   0 ); Out.Ln;
+  Out.Int( 3 - 2,   0 ); Out.Ln;
+  Out.Int( 3 * 2,   0 ); Out.Ln;
+  Out.Int( 3 DIV 2, 0 ); Out.Ln;
+  Out.Int( 3 MOD 2, 0 ); Out.Ln;
+
+  Out.Int( -0 ,   0 ); Out.Ln;  (* should output 0 of course, without the "-" *)
+END T01Arithmetic.

test/T02Precedence.mod

@@ -0,0 +1,7 @@
+MODULE T02Precedence;
+IMPORT Out;
+
+BEGIN
+  Out.Int( 1 + 2 * 3,   0 ); Out.Ln;
+  Out.Int( (1 + 2) * 3, 0 ); Out.Ln;
+END T02Precedence.

test/T10Constants.mod

@@ -0,0 +1,10 @@
+MODULE T10Constants;
+IMPORT Out;
+
+CONST x = 123; y = x * 2; abc="abc";
+BEGIN
+  Out.String( abc ); Out.Ln;
+  Out.Int( x,   0 ); Out.Ln;
+  Out.Int( y,   0 ); Out.Ln;
+  Out.Int( y-x, 0 ); Out.Ln;
+END T10Constants.

test/T11Variables.mod

@@ -0,0 +1,21 @@
+MODULE T11Variables;
+IMPORT Out;
+
+VAR x : INTEGER: msg : ARRAY 3 OF CHAR;
+BEGIN
+
+  x := 0;
+  Out.Int( x ); Out.Ln;
+  x := 1;
+  Out.Int( 1 ); Out.Ln;
+
+  x := 7; 
+  INC( x ); Out.Int( x ); Out.Ln;
+  DEC( x ); Out.Int( x ); Out.Ln;
+
+  msg := "abc";
+  Out.String( msg ); Out.Ln;
+  msg := "xyz";
+  Out.String( msg ); Out.Ln;
+
+END T11Variables.

test/T20IfThenElse.mod

@@ -0,0 +1,31 @@
+MODULE T20IfThenElse;
+IMPORT Out;
+
+VAR p : BOOLEAN; i : integer;
+BEGIN
+
+  p := TRUE;
+  IF p THEN Out.String( "P" ) ELSE Out.String( "~P" ) END; Out.Ln;
+  p := ~p;
+  IF p THEN Out.String( "P" ) ELSE Out.String( "~P" ) END; Out.Ln;
+
+  IF 1 # 2 THEN Out.String( "TRUE" ) ELSE Out.String( "FALSE" ) END; Out.Ln;
+  IF 1 = 2 THEN Out.String( "TRUE" ) ELSE Out.String( "FALSE" ) END; Out.Ln;
+  IF 1 > 2 THEN Out.String( "TRUE" ) ELSE Out.String( "FALSE" ) END; Out.Ln;
+  IF 1 < 2 THEN Out.String( "TRUE" ) ELSE Out.String( "FALSE" ) END; Out.Ln;
+  IF 1 >= 2 THEN Out.String( "TRUE" ) ELSE Out.String( "FALSE" ) END; Out.Ln;
+  IF 1 <= 2 THEN Out.String( "TRUE" ) ELSE Out.String( "FALSE" ) END; Out.Ln;
+
+  i := -1;
+  IF i > 0 THEN Out.String( "+" ) ELSIF i < 0 THEN Out.String( "-" ) ELSE Out.String("0") END;
+  Out.Ln;
+
+  i := 0;
+  IF i > 0 THEN Out.String( "+" ) ELSIF i < 0 THEN Out.String( "-" ) ELSE Out.String("0") END;
+  Out.Ln;
+
+  i := 1;
+  IF i > 0 THEN Out.String( "+" ) ELSIF i < 0 THEN Out.String( "-" ) ELSE Out.String("0") END;
+  Out.Ln;
+
+END T205IfThenElse.

test/T21Loops.mod

@@ -0,0 +1,26 @@
+MODULE T21Loops;
+IMPORT Out;
+
+VAR i : INTEGER;
+
+BEGIN
+ i := 0;
+
+ REPEAT INC( i ); Out.Int( i ); Out.Ln
+ UNTIL i = 10;
+
+ WHILE i > -10 DO 
+   DEC( i, 5 ); Out.Int( i ); Out.Ln
+ END;
+
+ WHILE i > -10 DO 
+   Out.String("This should not Appear");
+ ELSE
+
+ END;
+
+ FOR i := 1 TO 3 BY  1 DO Out.Int( i ); Out.Ln END;
+ FOR i := 3 TO 1 BY -1 DO Out.Int( i ); Out.Ln END;
+ FOR i := 8 TO 2 BY -2 DO Out.Int( i ); Out.Ln END;
+
+END T21Loops.

test/T30Procedures.mod

@@ -0,0 +1,30 @@
+MODULE T30Procedures;
+IMPORT Out;
+
+PROCEDURE WriteLn( i : INTEGER );
+BEGIN
+  Out.Int( i );
+  Out.Ln;
+END Write;
+
+PROCEDURE Next( i : INTEGER ) : INTEGER;
+BEGIN
+  RETURN i + 1
+END Next;
+
+PROCEDURE VarNext( i : INTEGER; VAR j : INTEGER );
+BEGIN
+END;
+
+VAR x : INTEGER;
+BEGIN
+
+  x := 0;
+  WriteLn( x );         (* 0 *)
+  x := Next( x );   
+  WriteLn( x );         (* 1 *)
+  WriteLn( Next( x ));  (* 2 *)
+  VarNext( x, x );
+  WriteLn( x );         (* 2 *)
+
+END T30Procedures.

test/T31Nested.mod

@@ -0,0 +1,18 @@
+PROCEDURE T31Nested;
+IMPORT Out;
+
+PROCEDURE Nested;
+  PROCEDURE N1;
+    PROCEDURE N2
+      PROCEDURE N3
+      BEGIN Out.String( "[ N3 ]" )
+      END N3;
+    BEGIN Out.String( "[ N2 " ); N3; Out.String( "]" )
+    END N2;
+  BEGIN Out.String( "[ N1 " ); N2; Out.String( "]" )
+  END N1;
+BEGIN Out.String( "[ Nested " ); N1; Out.String( "]" ); Out.Ln
+END Nested;
+
+BEGIN Nested
+END T31Nested.

test/T32Recursion.mod

@@ -0,0 +1,32 @@
+MODULE T32Recursion;
+
+
+PROCEDURE Binary( number, digits : INTEGER );
+  VAR place : INTEGER;
+
+  PROCEDURE Helper;
+    VAR bit : INTEGER;
+  BEGIN
+    IF ODD( number ) THEN bit := 1 ELSE bit := 0 END;
+    number := number DIV 2;
+    (* since we want to print the bits from highest to lowest,
+       but we're starting with the lowest, we need to put the
+       the recursive call in the middle. *)
+    IF place > 0 THEN
+      cursor := cursor - 1;
+      Helper;
+    END;
+    (* the above code recursively printed all the bits to our left,
+       so now we can print our bit and return: *)
+    Out.Int( bit )
+  END Helper;
+
+BEGIN
+  place := digits;
+  helper;
+  Out.Ln;
+END Binary;
+
+BEGIN
+  Binary( 5, 4 );   (* expect: 0101 *)
+END T32Recursion.