// Parse and translate a math factor
private int Factor()
{
if (Cradle.Look == '(')
{
Cradle.Match('(');
int value = Expression();
Cradle.Match(')');
return(value);
}
else if (Cradle.IsAlpha(Cradle.Look))
{
return(Table[Cradle.GetName() - 'A']);
}
else
{
return(Cradle.GetNum());
}
}
// Recognize and translate an if construct
private void DoIf(string L)
{
Cradle.Match('i');
BoolExpression();
string L1 = Label.NewLabel();
string L2 = L1;
Cradle.EmitLn("BEQ " + L1);
Block(L);
if (Cradle.Look == 'l')
{
Cradle.Match('l');
L2 = Label.NewLabel();
Cradle.EmitLn("BRA " + L2);
Label.PostLabel(L1);
Block(L);
}
Cradle.Match('e');
Label.PostLabel(L2);
}
// Parse and translate an expression
private int Expression()
{
int Value = (Cradle.IsAddop(Cradle.Look)) ? 0 : Term();
while (Cradle.IsAddop(Cradle.Look))
{
switch (Cradle.Look)
{
case '+':
Cradle.Match('+');
Value += Term();
break;
case '-':
Cradle.Match('-');
Value -= Term();
break;
}
}
return(Value);
}
// Parse and translate a math term
private int Term()
{
int Value = Factor();
while ("*/".IndexOf(Cradle.Look) > -1)
{
switch (Cradle.Look)
{
case '*':
Cradle.Match('*');
Value *= Factor();
break;
case '/':
Cradle.Match('/');
Value /= Factor();
break;
}
}
return(Value);
}
// Recognize and translate a Boolean or
private void BoolOr()
{
Cradle.Match('|');
BoolTerm();
Cradle.EmitLn("OR (SP)+,D0");
}
// Recognize and translate an add
private void Add()
{
Cradle.Match('+');
Term();
Cradle.EmitLn("ADD (SP)+,D0");
}
// Recognize and translate a multiply
private void Multiply()
{
Cradle.Match('*');
Factor();
Cradle.EmitLn("MULS (SP)+,D0");
}
// Recognize and translate an exclusive or
private void BoolXor()
{
Cradle.Match('~');
BoolTerm();
Cradle.EmitLn("EOR (SP)+,D0");
}
// Output routine
private void Output()
{
Cradle.Match('!');
Console.WriteLine(Table[Cradle.GetName() - 'A']);
}
// Input routine
private void Input()
{
Cradle.Match('?');
Assignment();
}