private System.Type TypeOfExpr(expr expr)
{
if (expr is StringLiteral)
{
return(typeof(string)); //setting the type of expr to type string
}
else if (expr is IntLiteral)
{
return(typeof(int)); //type to int
}
else if (expr is Variable)
{
Variable var = (Variable)expr;
if (this.symbolTable.ContainsKey(var.Ident))
{
Emit.LocalBuilder locb = symbolTable[var.Ident]; //loacal variable assigned the value of symbol table at key var.Ident
return(locb.LocalType);
}
else
{
throw new System.Exception("undeclared variable '" + var.Ident + "'");
}
}
else if (expr is BinExpr)
{
BinExpr var = (BinExpr)expr;
return(typeof(int));
}
else
{
throw new System.Exception("don't know how to calculate the type of " + expr.GetType().Name);
}
}
private void GenExpr(expr expr, System.Type expectedType)
{
System.Type deliveredType;
if (expr is StringLiteral)
{
deliveredType = typeof(string);
this.il.Emit(Emit.OpCodes.Ldstr, ((StringLiteral)expr).Value); //pushes the value of passed expression on string type stack
// il.EmitWriteLine("hello");
}
else if (expr is IntLiteral)
{
deliveredType = typeof(int);
this.il.Emit(Emit.OpCodes.Ldc_I4, ((IntLiteral)expr).Value); //pushes the value of passed expression on integer type stack
}
else if (expr is Variable)
{
string ident = ((Variable)expr).Ident;
deliveredType = this.TypeOfExpr(expr);
if (!this.symbolTable.ContainsKey(ident))
{
throw new System.Exception("undeclared variable '" + ident + "'");
}
this.il.Emit(Emit.OpCodes.Ldloc, this.symbolTable[ident]);
}
else if (expr is BinExpr)
{
BinExpr val = new BinExpr();
val = (BinExpr)expr;
deliveredType = typeof(int);
whole.Add(val.Left);
counter++;
//MessageBox.Show(whole.Count().ToString());
whole.Add(val.Op);
//counters++;
//MessageBox.Show(whole.Count().ToString());
if ((TypeOfExpr((expr)val.Right) == typeof(int) && (!(val.Right is BinExpr))) || val.Right is Variable)
{
whole.Add(val.Right);
//MessageBox.Show(whole.Count().ToString());
ADD_EMIT();
}
else
{
this.GenExpr(val.Right, this.TypeOfExpr(val.Right));
}
/*if (val.Left is IntLiteral)
*
* this.il.Emit(Emit.OpCodes.Ldc_I4, ((IntLiteral)val.Left).Value);//pushes the value of passed expression on integer type stack
* else
* {
* string ident = ((Variable)val.Left).Ident;
* Emit.LocalBuilder locb = this.symbolTable[ident];
* this.il.Emit(Emit.OpCodes.Ldloc, locb);
* }
*
*
* if ( (TypeOfExpr((expr)val.Right)== typeof(int) && (! (val.Right is BinExpr))) || val.Right is Variable)
* {
*
*
*
* MessageBox.Show("blah blah");
*
* if (val.Right is IntLiteral)
*
* this.il.Emit(Emit.OpCodes.Ldc_I4, ((IntLiteral)val.Right).Value);//pushes the value of passed expression on integer type stack
* else
* {
* string ident = ((Variable)val.Right).Ident;
* Emit.LocalBuilder locb = this.symbolTable[ident];
* this.il.Emit(Emit.OpCodes.Ldloc, locb);
* }
*
* if ((val.Op).Equals(BinOp.add))
* {
* this.il.Emit(Emit.OpCodes.Add);
* }
* else if ((val.Op).Equals(BinOp.minus))
* {
* this.il.Emit(Emit.OpCodes.Sub);
* }
* else if ((val.Op).Equals(BinOp.multiply))
* {
* this.il.Emit(Emit.OpCodes.Mul);
* }
* else if ((val.Op).Equals(BinOp.divide))
* {
* this.il.Emit(Emit.OpCodes.Div);
* }
*
* }
* else
* {
* this.GenExpr(val.Right, this.TypeOfExpr(val.Right));
* }*/
}
else
{
throw new System.Exception("don't know how to generate " + expr.GetType().Name);
}
if (deliveredType != expectedType) //type cheking
{
if (deliveredType == typeof(int) &&
expectedType == typeof(string))
{
this.il.Emit(Emit.OpCodes.Box, typeof(int));
this.il.Emit(Emit.OpCodes.Callvirt, typeof(object).GetMethod("ToString")); //parsing integer to string
//il.EmitCall(Emit.OpCodes.new
}
else
{
throw new System.Exception("can't coerce a " + deliveredType.Name + " to a " + expectedType.Name);
}
}
}
