23 files changed, 324 insertions, 18 deletions
diff --git a/SemanticCheckList.txt b/SemanticCheckList.txt
index f7fb1c7..446a442 100644
--- a/SemanticCheckList.txt
+++ b/SemanticCheckList.txt
@@ -4,38 +4,40 @@ DRAGON Semantic Checklist
 [X] 1. Semantic rules for Scoping
 [X]    1.1. Local objects cannot be declared more than once
 [X]    1.2. Local objects hide non-local objects with the same name
-[X]    1.3. Non-local objects should be visible from inner scopes (unless a local object of the same name exists)
-[X]    1.4. Function and procedure names exist in the scope they are defined (and not in their own scopes)
+[X]    1.3. Non-local objects should be visible from inner scopes
+            (unless a local object of the same name exists)
+[X]    1.4. Function and procedure names exist in the scope they are
+            defined (and not in their own scopes)
 [X]    1.5. Local objects cease to exist once their scopes cease to exist
 
 [X] 2. Semantic rules for Expressions
 [X]    2.1. Expressions return typed-values
 [X]    2.2. Objects must be declared before they used in expressions
-[X]    2.3. Objects of different types cannot appear in the same expression (no type promotions)
+[X]    2.3. Objects of different types cannot appear in the same
+            expression (no type promotions)
 
 [ ] 3. Semantic rules for Statements
 [ ]    3.1. Statements do not return values
-            TODO: Add check for return type on statements, parsing
-                      statement_list?
-[X]    3.2. The test expression for IF-THEN, IF-THEN-ELSE, WHILE-DO must be Boolean-valued;
-[X]         note that the Boolean type must be implicitly defined
-[X]    3.3. The ELSE clause always binds to the closest IF (resolution of the dangling ELSE problem)
-[ ]    3.4. The variable type in FOR-DO must match the types of lower bound and upper bound expressions
+[ ]    3.2. The test expression for IF-THEN, IF-THEN-ELSE, WHILE-DO
+            must be Boolean-valued;
+            note that the Boolean type must be implicitly defined
+[X]    3.3. The ELSE clause always binds to the closest IF (resolution
+            of the dangling ELSE problem)
+[X]    3.4. The variable type in FOR-DO must match the types of lower bound and upper bound expressions
 
-[ ] 4. Semantic rules for Arrays
+[X] 4. Semantic rules for Arrays
 [X]    4.1. Non-integer valued expressions cannot be used for indexing arrays
 
 [ ] 5. Semantic rules for Functions
-[X]    5.1. Function calls return values of type Integer or Real
+[ ]    5.1. Function calls return values of type Integer or Real
 [ ]    5.2. Function must contain a "return" statement within its own body;
             this is of the form: <function_name> := <expression>
-[ ]    5.3. Functions must accept exactly the same number of arguments as is
+[X]    5.3. Functions must accept exactly the same number of arguments as is
             declared in its header, with the correct sequence of types
-            TODO: Fix array types.
-[X]    5.4. Functions are not allowed to update the value of nonlocal objects (via assignment statements)
+[X]    5.4. Functions are not allowed to update the value of nonlocal
+            objects (via assignment statements)
 
-[ ] 6. Semantic rules for Procedures
-[ ]    6.1. Procedure calls do not return values
-[ ]    6.2. Procedures must accept exactly the same number of arguments as is
+[X] 6. Semantic rules for Procedures
+[X]    6.1. Procedure calls do not return values
+[X]    6.2. Procedures must accept exactly the same number of arguments as is
             declared in its header, with the correct sequence of types
-            TODO: Fix array types.
diff --git a/Testing/Semantic/t1-1a.p b/Testing/Semantic/t1-1a.p
new file mode 100644
index 0000000..5a6e773
--- /dev/null
+++ b/Testing/Semantic/t1-1a.p
@@ -0,0 +1,7 @@
+(* ERROR: variable redeclared *)
+program main( input, output );
+  var a,b,c: integer;
+  var x,y,c: real;
+begin
+end.
+
diff --git a/Testing/Semantic/t1-1b.p b/Testing/Semantic/t1-1b.p
new file mode 100644
index 0000000..5a16e62
--- /dev/null
+++ b/Testing/Semantic/t1-1b.p
@@ -0,0 +1,16 @@
+(* ERROR: variable redeclared *)
+program main( input, output );
+  var a: integer;
+
+  procedure boo;
+  begin
+  end;
+
+  function boo(b:integer):integer;
+  begin
+	boo := 1
+  end;
+
+begin
+end.
+
diff --git a/Testing/Semantic/t1-2.p b/Testing/Semantic/t1-2.p
new file mode 100644
index 0000000..62f2d94
--- /dev/null
+++ b/Testing/Semantic/t1-2.p
@@ -0,0 +1,12 @@
+(* LEGAL: local names should hide non-local names *)
+program main( input, output );
+  var a,b: integer;
+  procedure boo(a: integer);
+    var b: real;
+  begin
+    b := 1.23 
+  end;
+begin
+  boo(b)
+end.
+
diff --git a/Testing/Semantic/t1-2a.p b/Testing/Semantic/t1-2a.p
new file mode 100644
index 0000000..62f2d94
--- /dev/null
+++ b/Testing/Semantic/t1-2a.p
@@ -0,0 +1,12 @@
+(* LEGAL: local names should hide non-local names *)
+program main( input, output );
+  var a,b: integer;
+  procedure boo(a: integer);
+    var b: real;
+  begin
+    b := 1.23 
+  end;
+begin
+  boo(b)
+end.
+
diff --git a/Testing/Semantic/t1-2b.p b/Testing/Semantic/t1-2b.p
new file mode 100644
index 0000000..fd32c49
--- /dev/null
+++ b/Testing/Semantic/t1-2b.p
@@ -0,0 +1,12 @@
+(* LEGAL: local names should hide non-local names *)
+program main( input, output );
+  var a,b: integer;
+  procedure boo(a: integer);
+    var b: real;
+  begin
+    b := 1
+  end;
+begin
+  boo(b)
+end.
+
diff --git a/Testing/Semantic/t1-3.p b/Testing/Semantic/t1-3.p
new file mode 100644
index 0000000..a224b22
--- /dev/null
+++ b/Testing/Semantic/t1-3.p
@@ -0,0 +1,11 @@
+(* LEGAL: non-local names visible from inner scopes *)
+program main( input, output );
+  var a: integer;
+  procedure boo(x: integer);
+  begin
+    a := x
+  end;
+begin
+  boo(a)
+end.
+
diff --git a/Testing/Semantic/t1-4.p b/Testing/Semantic/t1-4.p
new file mode 100644
index 0000000..420bdcb
--- /dev/null
+++ b/Testing/Semantic/t1-4.p
@@ -0,0 +1,13 @@
+(* LEGAL: scope of the name of subprograms *)
+program main( input, output );
+  procedure boo;
+    procedure foo;
+    begin
+    end;
+  begin
+    foo
+  end;
+begin
+  boo
+end.
+
diff --git a/Testing/Semantic/t1-5.p b/Testing/Semantic/t1-5.p
new file mode 100644
index 0000000..d2341d7
--- /dev/null
+++ b/Testing/Semantic/t1-5.p
@@ -0,0 +1,11 @@
+(* ERROR: local objects not defined outside their scopes *)
+program main( input, output );
+  var a: integer;
+  procedure boo(a: integer);
+    var x: integer;
+  begin
+  end;
+begin
+  a := x
+end.
+
diff --git a/Testing/Semantic/t2-1.p b/Testing/Semantic/t2-1.p
new file mode 100644
index 0000000..295fe4b
--- /dev/null
+++ b/Testing/Semantic/t2-1.p
@@ -0,0 +1,10 @@
+(* expression must return a typed-value *)
+program main(input,output);
+ var a,b,c: integer;
+ var x,y,z: real;
+begin
+ a := b + c;
+ x := y + z;
+ a := x
+end.
+
diff --git a/Testing/Semantic/t2-2.p b/Testing/Semantic/t2-2.p
new file mode 100644
index 0000000..efb455b
--- /dev/null
+++ b/Testing/Semantic/t2-2.p
@@ -0,0 +1,6 @@
+(* ERROR: objects must be declared before used in expressions *)
+program main( input, output );
+begin
+  a := 1
+end.
+
diff --git a/Testing/Semantic/t2-3.p b/Testing/Semantic/t2-3.p
new file mode 100644
index 0000000..806c575
--- /dev/null
+++ b/Testing/Semantic/t2-3.p
@@ -0,0 +1,9 @@
+(* ERROR: objects of different types appear in the same expression *)
+program main( input, output );
+  var a: integer;
+  var x: real;
+begin
+  a := a + 1.23;
+  x := x + 123
+end.
+
diff --git a/Testing/Semantic/t3-2.p b/Testing/Semantic/t3-2.p
new file mode 100644
index 0000000..22f9b47
--- /dev/null
+++ b/Testing/Semantic/t3-2.p
@@ -0,0 +1,8 @@
+(* ERROR: test expressions in IF/WHILE statements must be Boolean *)
+program main( input, output );
+  var a: integer;
+begin
+  while a + 123 do
+    a := a + 1
+end.
+
diff --git a/Testing/Semantic/t3-3.p b/Testing/Semantic/t3-3.p
new file mode 100644
index 0000000..32b5e59
--- /dev/null
+++ b/Testing/Semantic/t3-3.p
@@ -0,0 +1,13 @@
+(* dangling ELSE binds to closest IF *)
+program main( input, output );
+  var a: integer;
+begin
+  read(a);
+  if ( a < 10 ) then
+    if ( a >= 10 ) then
+      a := 1
+  else
+      a := 0;
+  write(a)
+end.
+
diff --git a/Testing/Semantic/t3-3a.p b/Testing/Semantic/t3-3a.p
new file mode 100644
index 0000000..45d92f1
--- /dev/null
+++ b/Testing/Semantic/t3-3a.p
@@ -0,0 +1,13 @@
+(* dangling ELSE binds to closest IF *)
+program main( input, output );
+  var a: integer;
+begin
+  a := 5;
+  if ( a < 10 ) then
+    if ( a >= 10 ) then
+      a := 1
+  else
+      a := 0;
+a:=2
+end.
+
diff --git a/Testing/Semantic/t3-4.p b/Testing/Semantic/t3-4.p
new file mode 100644
index 0000000..73dc520
--- /dev/null
+++ b/Testing/Semantic/t3-4.p
@@ -0,0 +1,9 @@
+(* ERROR: mismatched type for index variable in FOR loops *)
+program main( input, output );
+  var a: integer;
+  var x: real;
+begin
+  for x := 1 to 5 do
+    a := a + 1
+end.
+
diff --git a/Testing/Semantic/t4-1.p b/Testing/Semantic/t4-1.p
new file mode 100644
index 0000000..2f24e8c
--- /dev/null
+++ b/Testing/Semantic/t4-1.p
@@ -0,0 +1,8 @@
+(* ERROR: non-integer type for array index *)
+program main( input, output );
+  var a: array[3 .. 7] of real;
+  var x: real;
+begin
+  a[x] := 1.23
+end.
+
diff --git a/Testing/Semantic/t5-2.p b/Testing/Semantic/t5-2.p
new file mode 100644
index 0000000..2b9cde3
--- /dev/null
+++ b/Testing/Semantic/t5-2.p
@@ -0,0 +1,8 @@
+(* ERROR: function missing return statement *)
+program main( input, output );
+  function foo(a: integer): integer;
+  begin
+  end;
+begin
+end.
+
diff --git a/Testing/Semantic/t5-3.p b/Testing/Semantic/t5-3.p
new file mode 100644
index 0000000..6494ae0
--- /dev/null
+++ b/Testing/Semantic/t5-3.p
@@ -0,0 +1,18 @@
+(* ERROR: function passed wrong number/type of arguments *)
+program main( input, output );
+  var b: integer;
+  var y: real;
+  var a: array[1 .. 13] of integer;
+  var z: array[1 .. 13] of real;
+
+  function foo(a: integer; x: real): integer;
+  begin
+    foo := a
+  end;
+begin
+  b := foo(y,b) + foo(b,y,10)
+end.
+
+
+
+
diff --git a/Testing/Semantic/t5-4.p b/Testing/Semantic/t5-4.p
new file mode 100644
index 0000000..840625a
--- /dev/null
+++ b/Testing/Semantic/t5-4.p
@@ -0,0 +1,14 @@
+(* ERROR: function updating non-local variable *)
+program main( input, output );
+  var a: integer;
+  
+  function foo(b: integer): integer;
+  begin
+    foo := a;
+    a := b
+  end;
+
+begin
+
+end.
+
diff --git a/Testing/Semantic/t6-1.p b/Testing/Semantic/t6-1.p
new file mode 100644
index 0000000..9669168
--- /dev/null
+++ b/Testing/Semantic/t6-1.p
@@ -0,0 +1,11 @@
+(* ERROR: procedures don't return values *)
+program main( input, output );
+  var a: integer;
+  procedure boo(b: integer);
+  begin
+    a := 1
+  end;
+begin
+  a := boo(a)
+end.
+
diff --git a/Testing/Semantic/t6-2.p b/Testing/Semantic/t6-2.p
new file mode 100644
index 0000000..3eabfac
--- /dev/null
+++ b/Testing/Semantic/t6-2.p
@@ -0,0 +1,13 @@
+(* ERROR: procedure passed wrong number/type of arguments *)
+program main( input, output );
+  var b: integer;
+  var y: real;
+
+  procedure boo(a: integer; x: real);
+  begin
+  end;
+begin
+  boo(y,10);
+  boo(b,y,b)
+end.
+
diff --git a/Testing/Semantic/test-semantic.p b/Testing/Semantic/test-semantic.p
new file mode 100644
index 0000000..2cb9b8a
--- /dev/null
+++ b/Testing/Semantic/test-semantic.p
@@ -0,0 +1,70 @@
+
+program main( input, output );
+
+  (* local variables *)
+  var x, y: integer;
+  var a, b: real;
+  var c: array[ 1..10 ] of integer;
+  var d: array[ 11..20 ] of real;
+
+  (* local function: mixed argument types *)
+  function foo( a: integer; x: real; z: integer ): integer;
+	procedure boo( a: real );
+	begin
+		(* scope check on boo's a, main's b, d[] and y; and foo's z*)
+		boo( a * b + d[y + z] )	
+	end;
+  begin
+	(* boo is visible; so is main's b *)
+	boo( b );	
+
+	(* function return statement; scope and type check on foo's a and main's y *)
+	foo := a + y
+  end;
+
+  (* local procedure *)
+  procedure bar( c: integer );
+  begin
+	(* nonlocal update *)
+	d[ c[foo(x,a,y)] ] := b
+  end;
+
+  (* location function: recursive *)
+  function moo( d: integer ): integer;
+  begin
+	if ( d = 0 ) then
+		moo := 1
+	else
+		moo := d * moo( d - 1 )
+  end;
+
+begin
+
+  (* FUNCTION call check: recursive and correct arguments *)
+  y := foo( x + foo( y, 0.001, a ) * 1, 2.3, b );
+  
+  (* ARRAY access check: recursive, correct arguments *)
+  y := c[ x + c[y] * 45 ];
+
+  (* FUNCTION call and ARRAY access *)
+  y := foo( x + c[y + foo(c[1], d[2], a)] * 1, 2.3 + d[c[foo(c[3],b,d[y])]] );
+
+  (* IF-THEN check *) 
+  if ( c[x] * 6 < 7 + moo( y ) and a > d[c[x]] ) then
+  begin
+	c[moo(foo(8,9.10,11.0)) + c[12]] := moo( c[y - 1] )
+  end;
+
+  (* PROCEDURE call: correct arguments, not used as expression *)
+  bar( c[x] );
+
+  (* FOR check *)
+  b := 10.0;
+  for a := 1.0 to 2.0 * b do
+  begin
+	bar( c[x + moo( c[x + moo( c[x + moo(1)] )] )] );
+	a := a + 0.0000001
+  end
+
+end.
+