public static bool HasReturn(IStatement s)
{
if (s is Skip || s is Assignment)
{
return(false);
}
if (s is Conditional)
{
Conditional c = (Conditional)s;
return(HasReturn(c.ThenBranch()) || HasReturn(c.ElseBranch()));
}
if (s is Loop)
{
return(HasReturn(((Loop)s).Body()));
}
if (s is Block)
{
Block b = (Block)s;
IEnumerator <IStatement> it = b.GetMembers();
while (it.MoveNext())
{
if (HasReturn(it.Current))
{
return(true);
}
}
return(false);
}
if (s is Return)
{
return(true);
}
throw new IException("Semantic Error", "", "Semantic", 0, 0);
}
public static Value InterpretWithReturn(IStatement s, Functions funcs, State state)
{
state.Display();
if (s is Conditional)
{
Conditional c = (Conditional)s;
IStatement chosen;
if (Interpret(c.Test(), funcs, state).DBoolValue())
{
chosen = c.ThenBranch();
}
else
{
chosen = c.ElseBranch();
}
if (chosen is Return)
{
return(Interpret(((Return)chosen).Result(), funcs, state));
}
else
{
return(InterpretWithReturn(chosen, funcs, state));
}
}
if (s is Loop)
{
Loop l = (Loop)s;
if (Interpret(l.Test(), funcs, state).DBoolValue())
{
return(InterpretWithReturn(l, funcs, Interpret(l.Body(), funcs, state)));
}
}
if (s is Block)
{
Block b = (Block)s;
IEnumerator <IStatement> it = b.GetMembers();
while (it.MoveNext())
{
IStatement bs = it.Current;
if (bs is Skip)
{
continue;
}
if (bs is Return)
{
return(Interpret(((Return)s).Result(), funcs, state));
}
else
{
state = Interpret(s, funcs, state);
}
}
}
if (s is Return)
{
return(Interpret(((Return)s).Result(), funcs, state));
}
throw new IException("tried to Interpret statement with return when it didn't have a return", "", "Semantic", 0, 0);
}
public static State Interpret(Conditional c, Functions funcs, State state)
{
if (Interpret(c.Test(), funcs, state).DBoolValue())
{
return(Interpret(c.ThenBranch(), funcs, state));
}
else
{
return(Interpret(c.ElseBranch(), funcs, state));
}
}
public static bool IsSkipped(Conditional c, Functions funcs, State state)
{
IStatement chosen;
if (Interpret(c.Test(), funcs, state).DBoolValue())
{
chosen = c.ThenBranch();
}
else
{
chosen = c.ElseBranch();
}
return(chosen is Skip);
}
public static IStatement Transform(IStatement s, Functions funcs, TypeMap tm)
{
if (s is Skip || s is Return || s is Call)
{
return(s);
}
if (s is Assignment)
{
Assignment a = (Assignment)s;
Variable target = a.Target();
IExpression src = a.Source();
Type targettype = (Type)tm[a.Target()];
Type srctype = StaticTypeCheck.TypeOf(a.Source(), funcs, tm);
if (targettype == Type.FLOAT)
{
if (srctype == Type.INT)
{
src = new Unary(new Operator(Operator.FLOAT), src);
srctype = Type.FLOAT;
}
}
else if (targettype == Type.INT)
{
if (srctype == Type.CHAR)
{
src = new Unary(new Operator(Operator.INT), src);
srctype = Type.INT;
}
else if (srctype == Type.FLOAT)
{
src = new Unary(new Operator(Operator.INT), src);
srctype = Type.INT;
}
}
StaticTypeCheck.Check(targettype == srctype, "bug in assignment to " + target);
return(new Assignment(target, src));
}
if (s is Conditional)
{
Conditional c = (Conditional)s;
IExpression test = c.Test();
IStatement tbr = Transform(c.ThenBranch(), funcs, tm);
IStatement ebr = Transform(c.ElseBranch(), funcs, tm);
return(new Conditional(test, tbr, ebr));
}
if (s is Loop)
{
Loop l = (Loop)s;
IExpression test = l.Test();
IStatement body = l.Body();
return(new Loop(test, body));
}
if (s is Block)
{
Block b = (Block)s;
Block @out = new Block();
IEnumerator <IStatement> members = b.GetMembers();
while (members.MoveNext())
{
@out.AddMember(Transform(members.Current, funcs, tm));
}
return(@out);
}
throw new IException("Semantic Error", "", "Semantic", 0, 0);
}
public static void Validate(IStatement s, Functions funcs, TypeMap tm)
{
if (s == null)
{
throw new IException("TypeChecking: null statement", "", "Semantic", 0, 0);
}
else if (s is Skip)
{
return;
}
else if (s is Assignment)
{
Assignment a = (Assignment)s;
Check(tm.ContainsKey(a.Target()), "Target not found in type map! (target: " + a.Target() + ")");
Validate(a.Source(), funcs, tm);
Type targettype = (Type)tm[a.Target()];
Type srctype = TypeOf(a.Source(), funcs, tm);
if (targettype != srctype)
{
if (targettype == Type.FLOAT)
{
Check(srctype == Type.INT, "Caught mixed mode assignment in static type Checker from " + srctype + " to " + targettype + " (target: " + a.Target() + ")");
}
else if (targettype == Type.INT)
{
Check(srctype == Type.CHAR || srctype == Type.FLOAT, "Caught mixed mode assignment in static type Checker from " + srctype + " to " + targettype + " (target: " + a.Target() + ")");
}
else
{
Check(false, "Caught mixed mode assignment in static type Checker from " + srctype + " to " + targettype + " (target: " + a.Target() + ")");
}
}
return;
}
else if (s is Block)
{
Block b = (Block)s;
IEnumerator <IStatement> members = b.GetMembers();
while (members.MoveNext())
{
Validate(members.Current, funcs, tm);
}
}
else if (s is Loop)
{
Loop l = (Loop)s;
Validate(l.Test(), funcs, tm);
Validate(l.Body(), funcs, tm);
}
else if (s is Conditional)
{
Conditional c = (Conditional)s;
Validate(c.Test(), funcs, tm);
Validate(c.ThenBranch(), funcs, tm);
Validate(c.ElseBranch(), funcs, tm);
}
else if (s is Return)
{
Return r = (Return)s;
Function f = funcs[r.FunctionName().ToString()];
Type t = TypeOf(r.Result(), funcs, tm);
Check(t == f.type(), "Return expression doesn't match function's return type! (got a " + t + ", expected a " + f.type() + ")");
}
else
{
throw new IException("Type Checking Error : " + s, "", "Semantic", 0, 0);
}
}