public static Node parseStatement()
{
Node output;
if (tokens.actual.type == TokenType.IDENTIFIER)
{
Node identifier = new Identifier(tokens.actual.Copy());
tokens.selectNext();
output = new Assignment(tokens.actual.Copy(), new List <Node>()
{
identifier
});
tokens.selectNext();
output.children.Add(parseExpression());
}
else if (tokens.actual.type == TokenType.CALL)
{
tokens.selectNext();
if (tokens.actual.type != TokenType.IDENTIFIER)
{
throw new Exception("Expecting sub identifier after call token");
}
Token funcIdentifier = tokens.actual.Copy();
tokens.selectNext();
if (tokens.actual.type != TokenType.PARENTHESESBEGIN)
{
throw new Exception("Expecting ( after sub identifier");
}
tokens.selectNext();
List <Node> arguments = new List <Node>();
if (tokens.actual.type == TokenType.PARENTHESESEND)
{
tokens.selectNext();
}
else
{
arguments.Add(parseExpression());
while (tokens.actual.type == TokenType.COMA)
{
tokens.selectNext();
arguments.Add(parseExpression());
}
if (tokens.actual.type != TokenType.PARENTHESESEND)
{
throw new Exception("Exepecting ) to finish sub call");
}
tokens.selectNext();
}
output = new SubCall(funcIdentifier, arguments);
}
else if (tokens.actual.type == TokenType.PRINT)
{
output = new Print(tokens.actual.Copy(), new List <Node>());
tokens.selectNext();
output.children.Add(parseExpression());
}
else if (tokens.actual.type == TokenType.DIM)
{
output = new VarDec(tokens.actual.Copy(), new List <Node>());
tokens.selectNext();
if (tokens.actual.type == TokenType.IDENTIFIER)
{
output.children.Add(new Identifier(tokens.actual.Copy()));
tokens.selectNext();
if (tokens.actual.type == TokenType.AS)
{
tokens.selectNext();
output.children.Add(parseType());
}
else
{
throw new Exception("Invalid Syntax - Expecting As token");
}
}
else
{
throw new Exception("Invalid Syntax - Expecting Identifier after DIM");
}
}
else if (tokens.actual.type == TokenType.WHILE)
{
output = new While(tokens.actual.Copy(), new List <Node>());
tokens.selectNext();
output.children.Add(parseRelExpression());
if (tokens.actual.type != TokenType.BREAKLINE)
{
throw new Exception("Invalid Syntax -> Expecting new line");
}
tokens.selectNext();
Node whileStatements = new Statements(tokens.actual.Copy(), new List <Node>());
while (tokens.actual.type != TokenType.WEND)
{
whileStatements.children.Add(parseStatement());
if (tokens.actual.type != TokenType.BREAKLINE)
{
throw new Exception("Invalid Syntax -> Expecting new line");
}
tokens.selectNext();
}
output.children.Add(whileStatements);
tokens.selectNext();
}
else if (tokens.actual.type == TokenType.IF)
{
output = new If(tokens.actual.Copy(), new List <Node>());
tokens.selectNext();
Node firstSon = parseRelExpression();
if (tokens.actual.type == TokenType.THEN)
{
tokens.selectNext();
if (tokens.actual.type != TokenType.BREAKLINE)
{
throw new Exception("Invalid Syntax -> Expecting new line");
}
tokens.selectNext();
Node secondSon = new Statements(tokens.actual.Copy(), new List <Node>());
while ((tokens.actual.type != TokenType.ELSE) && (tokens.actual.type != TokenType.END))
{
secondSon.children.Add(parseStatement());
if (tokens.actual.type != TokenType.BREAKLINE)
{
throw new Exception("Invalid Syntax -> Expecting new line");
}
tokens.selectNext();
}
output.children.Add(firstSon);
output.children.Add(secondSon);
}
else
{
throw new Exception("Invalid Syntax -> Missing THEN");
}
if (tokens.actual.type == TokenType.ELSE)
{
tokens.selectNext();
if (tokens.actual.type != TokenType.BREAKLINE)
{
throw new Exception("Invalid Syntax -> Expecting new line");
}
tokens.selectNext();
Node thirdSon = new Statements(tokens.actual.Copy(), new List <Node>());
while (tokens.actual.type != TokenType.END)
{
thirdSon.children.Add(parseStatement());
if (tokens.actual.type != TokenType.BREAKLINE)
{
throw new Exception("Invalid Syntax -> Expecting new line");
}
tokens.selectNext();
}
output.children.Add(thirdSon);
tokens.selectNext();
if (tokens.actual.type == TokenType.CONDICAO)
{
tokens.selectNext();
}
else
{
throw new Exception("Invalid Syntax -> Missing IF of END IF");
}
}
else if (tokens.actual.type == TokenType.END)
{
tokens.selectNext();
if (tokens.actual.type == TokenType.CONDICAO)
{
tokens.selectNext();
}
else
{
throw new Exception("Invalid Syntax -> Missing IF of END IF");
}
}
else
{
throw new Exception("Invalid Syntax -> Missing END IF");
}
}
else
{
output = new NoOp();
}
return(output);
}
public static Node parseFuncDec()
{
tokens.selectNext();
if (tokens.actual.type != TokenType.IDENTIFIER)
{
throw new Exception("Expecting Identifier after function token");
}
Token actualToken = tokens.actual.Copy();
tokens.selectNext();
if (tokens.actual.type != TokenType.PARENTHESESBEGIN)
{
throw new Exception("Expecting ( token");
}
tokens.selectNext();
if ((tokens.actual.type != TokenType.PARENTHESESEND) &&
(tokens.actual.type != TokenType.IDENTIFIER))
{
throw new Exception("Expecting ) or variable declaration");
}
List <Node> varDecs = new List <Node>();
if (tokens.actual.type == TokenType.IDENTIFIER)
{
Node vardec;
vardec = new VarDec(tokens.actual.Copy(), new List <Node>());
vardec.children.Add(new Identifier(tokens.actual.Copy()));
tokens.selectNext();
if (tokens.actual.type != TokenType.AS)
{
throw new Exception("Expecting AS after identifier declaration");
}
tokens.selectNext();
vardec.children.Add(parseType());
varDecs.Add(vardec);
while (tokens.actual.type == TokenType.COMA)
{
tokens.selectNext();
vardec = new VarDec(tokens.actual.Copy(), new List <Node>());
vardec.children.Add(new Identifier(tokens.actual.Copy()));
tokens.selectNext();
if (tokens.actual.type != TokenType.AS)
{
throw new Exception("Expecting AS after identifier declaration");
}
tokens.selectNext();
vardec.children.Add(parseType());
varDecs.Add(vardec);
}
}
tokens.selectNext(); //skipping )
if (tokens.actual.type != TokenType.AS)
{
throw new Exception("Expecting AS after identifier of func");
}
tokens.selectNext();
Node tree = new FuncDec(actualToken, varDecs, parseType());
if (tokens.actual.type != TokenType.BREAKLINE)
{
throw new Exception("Expecting new Line");
}
tokens.selectNext();
Node statements = new Statements(new Token(), new List <Node>());
if (tokens.Spy().type == TokenType.END)
{
tokens.selectNext();
if (tokens.actual.type != TokenType.FUNCTION)
{
throw new Exception("Expecting FUNCTION after END");
}
tokens.selectNext();
tree.children.Add(statements);
return(tree);
}
statements.children.Add(parseStatement());
if (tokens.actual.type != TokenType.BREAKLINE)
{
throw new Exception("Expecting breakline");
}
tokens.selectNext();
while (tokens.actual.type != TokenType.END)
{
statements.children.Add(parseStatement());
if (tokens.actual.type != TokenType.BREAKLINE)
{
throw new Exception("Expecting breakline");
}
tokens.selectNext();
}
tokens.selectNext();
if (tokens.actual.type != TokenType.FUNCTION)
{
throw new Exception("Expecting FUNCTION after END TOKEN");
}
tokens.selectNext();
tree.children.Add(statements);
if ((tokens.actual.type != TokenType.BREAKLINE) && (tokens.actual.type != TokenType.EOF))
{
throw new Exception("Expecting breakline");
}
tokens.selectNext();
return(tree);
}
