public override void ExecuteDirective()
{
if (Assembler.CurrentLine.InstructionName.Equals(".next"))
{
foreach (Token child in _iterations.Children)
{
if (!child.HasChildren)
{
throw new ExpressionException(child.Position, "Iteration expression cannot be empty.");
}
if (!Assembler.SymbolManager.SymbolExists(child.Children[0].Name))
{
throw new ExpressionException(child.Children[0].Position,
$"Variable \"{child.Children[0].Name}\" must be defined before it is used.");
}
Assembler.SymbolManager.Define(child.Children, true);
}
if (_condition == null || Evaluator.EvaluateCondition(_condition))
{
Assembler.LineIterator.Rewind(Index);
}
}
}
void EvaluateCondition(SourceLine line)
{
if (line.InstructionName.EndsWith("ndef"))
{
_ifTrue = !Assembler.SymbolManager.SymbolExists(line.OperandExpression);
}
else if (line.InstructionName.EndsWith("def"))
{
_ifTrue = Assembler.SymbolManager.SymbolExists(line.OperandExpression);
}
else
{
_ifTrue = Evaluator.EvaluateCondition(line.Operand.Children);
}
if (line.InstructionName.EndsWith("def"))
{
// save the evaluation
line.Instruction.Name = Regex.Replace(line.Instruction.Name, @"n?def", string.Empty);
line.Operand = new Token
{
Type = TokenType.Operator,
OperatorType = OperatorType.Separator,
Children = new List <Token>
{
new Token
{
Type = TokenType.Operator,
OperatorType = OperatorType.Separator,
Children = new List <Token>
{
new Token
{
Name = _ifTrue.ToString().ToLower(),
Type = TokenType.Operand
}
}
}
}
};
}
}
void DoAssert(SourceLine line)
{
if (line.Operand.Children == null || !line.Operand.HasChildren)
{
Assembler.Log.LogEntry(line, line.Operand, "One or more arguments expected for assertion directive.");
}
else if (line.Operand.Children.Count > 2)
{
Assembler.Log.LogEntry(line, line.Operand.Children[2], "Unexpected expression found.");
}
else if (!Evaluator.EvaluateCondition(line.Operand.Children[0]))
{
if (line.Operand.Children.Count > 1)
{
Output(line, line.Operand.Children[1]);
}
else
{
Output(line, "Assertion failed.");
}
}
}
void ThrowConditional(SourceLine line)
{
if (line.Operand.Children == null ||
line.Operand.Children.Count < 2 ||
!line.Operand.Children[1].HasChildren)
{
Assembler.Log.LogEntry(line, line.Operand, $"Missing arguments for directive \"{line.InstructionName}\".");
}
else if (line.Operand.Children.Count > 2 || !line.Operand.Children[1].Children[0].ToString().EnclosedInDoubleQuotes())
{
Assembler.Log.LogEntry(line, line.Operand, $"Argument error for directive \"{line.InstructionName}\".");
}
else if (Evaluator.EvaluateCondition(line.Operand.Children[0].Children))
{
if (line.Operand.Children.Count > 1)
{
Output(line, line.Operand.Children[1]);
}
else
{
Output(line, $"Expression \"{line.UnparsedSource.Substring(line.Operand.Position)}\" evaluated to true.");
}
}
}