public List<Statement> Parse()
{
List<Statement> statements = new List<Statement>();
while(true)
{
while (Match(TokenType.LINE)) ;
if (Match("PRINT"))
{
statements.Add(new PrintStatement(Exp()));
}
else if (Match("INPUT"))
{
statements.Add(new InputStatement(Consume(TokenType.IDENTIFIER).Text, chameleon));
}
else if (Match("GOTO"))
{
statements.Add(new GotoStatement(Consume(TokenType.IDENTIFIER).Text, chameleon));
}
else if (Match("IF"))
{
Expression condition = Exp();
Consume("THEN");
string label = Consume(TokenType.IDENTIFIER).Text;
statements.Add(new IfThenStatement(condition, label, chameleon));
}
else if (Match("EXIT"))
{
statements.Add(new ExitStatement());
}
else if (Match("CLEAR"))
{
statements.Add(new ClearStatement());
}
else if (Match("WAIT"))
{
statements.Add(new WaitStatement());
}
else if (Match("TITLE"))
{
statements.Add(new TitleStatement(Consume(TokenType.STRING).Text));
}
else if (Match(TokenType.LABEL))
{
chameleon.labels[Last(1).Text] = statements.Count;
}
else if (Match(TokenType.IDENTIFIER, TokenType.ASSIGN))
{
string name = Last(2).Text;
string op = Last(1).Text;
Expression value = Exp();
statements.Add(new AssignStatement(name, value, chameleon, op));
}
else if (Match(TokenType.IDENTIFIER, TokenType.SPE_OPERATOR))
{
string name = Last(2).Text;
string op = Last(1).Text;
Expression value = new NumberValue(1);
statements.Add(new AssignStatement(name, value, chameleon, op));
}
else break;
}
return statements;
}
private Expression Op()
{
Expression expression = Atomic();
while(Match(TokenType.OPERATOR) || Match(TokenType.COMP_OPERATOR))
{
string op = Last(1).Text;
Expression right;
if (op == "++" || op == "--")
right = new NumberValue(1);
else
right = Atomic();
expression = new OperatorExpression(expression, op, right);
}
return expression;
}
