private AST_expression Parse_expression(TokenKind followSet)
{
IncrementDepth();
DebugPrint("expr");
AST_expression expression;
Token t = LookAheadToken();
switch (t.Kind)
{
case Exclamation:
expression = Parse_unary_operator_operand(followSet);
break;
default:
if (isMemberOf(t.Kind, FirstSet_operand))
{
AST_operand left_operand = Parse_operand(followSet | BinaryOperators);
if (IsBinaryOperator(LookAheadToken().Kind))
{
AST_binary_operator binary_operator = Parse_binary_operator(followSet);
AST_operand right_operand = Parse_operand(followSet);
binary_operator.SetLeft(left_operand);
binary_operator.SetRight(right_operand);
expression = binary_operator;
}
else
{
expression = left_operand;
}
}
else
{
Error("Expression expected. '" + t.ToString() + "' does not start an expression.", t);
expression = new ASTDummy_operand();
SkipUntilFollow(followSet);
}
break;
}
DecrementDepth();
return(expression);
}
public AST_unary_operator(AST_operand operand)
{
this.operand = operand;
}
public void SetLeft(AST_operand left)
{
this.left = left;
}
public void SetRight(AST_operand right)
{
this.right = right;
}
public AST_binary_operator(OperatorKind kind, AST_operand left, AST_operand right)
{
this.kind = kind;
this.left = left;
this.right = right;
}
