public ForNode(Var counter, VisitableNode from, VisitableNode to, List <VisitableNode> statements)
{
this.counter = counter;
this.from = from;
this.to = to;
this.statements = statements;
}
public Print Print()
{
/*
* Print: PRINT Expr
*/
VisitableNode n = Expr();
return(new Print(n));
}
public Assert AssertionStatement()
{
/*
* AssertionStatement: ASSERT LPAREN expr RPAREN
*/
Eat(TokenValues.ASSERT);
Eat(TokenValues.LPAREN);
VisitableNode n = Expr();
Eat(TokenValues.RPAREN);
return(new Assert(n));
}
public VisitableNode Statement()
{
/* For now only assignment statements and empties
* Statement : AssignmentStatement
| VariableDeclaration
| Print
| Empty
| AssertionStatement
| ReadStatement
| ForStatement
*/
VisitableNode result = null;
if (this.currentToken.GetTokenValueType() == TokenValues.ID)
{
result = AssignmentStatement();
}
else if (this.currentToken.GetTokenValueType() == TokenValues.VAR)
{
Eat(TokenValues.VAR);
result = VariableDeclaration();
}
else if (this.currentToken.GetTokenValueType() == TokenValues.PRINT)
{
Eat(TokenValues.PRINT);
result = Print();
}
else if (this.currentToken.GetTokenValueType() == TokenValues.ASSERT)
{
result = AssertionStatement();
}
else if (this.currentToken.GetTokenValueType() == TokenValues.READ)
{
result = ReadStatement();
}
else if (this.currentToken.GetTokenValueType() == TokenValues.FOR)
{
result = ForStatement();
}
else
{
result = Empty();
}
return(result);
}
public dynamic Expr()
{
VisitableNode result = Term();
HashSet <TokenValues> values = new HashSet <TokenValues>();
values.Add(TokenValues.PLUS);
values.Add(TokenValues.MINUS);
values.Add(TokenValues.EQUAL);
values.Add(TokenValues.LESSTHAN);
/*
* expr : Term ((PLUS|MINUS|EQUAL|LESSTHAN) Term) *
* Term : Factor ((MUL|DIV) Factor) *
* Factor : INTEGER | LPAREN expr RPAREN | Variable | STRING | TRUE | FALSE
*/
while (values.Contains(this.currentToken.GetTokenValueType()))
{
TokenValues type = this.currentToken.GetTokenValueType();
Token curr = this.currentToken;
switch (type)
{
case TokenValues.MINUS:
Eat(TokenValues.MINUS);
break;
case TokenValues.PLUS:
Eat(TokenValues.PLUS);
break;
case TokenValues.EQUAL:
Eat(TokenValues.EQUAL);
break;
case TokenValues.LESSTHAN:
Eat(TokenValues.LESSTHAN);
break;
default:
throw new InterpreterException("syntax error");
}
result = new BinOp(result, curr, this.Term());
}
return(result);
}
public ForNode ForStatement()
{
/*
* ForStatement: FOR Var IN Expr DDOT Expr DO Statements END FOR
*/
Eat(TokenValues.FOR);
Var v = Variable();
Eat(TokenValues.IN);
VisitableNode from = Expr();
Eat(TokenValues.DDOT);
VisitableNode to = Expr();
Eat(TokenValues.DO);
List <VisitableNode> s = Statements();
Eat(TokenValues.END);
Eat(TokenValues.FOR);
return(new ForNode(v, from, to, s));
}
public List <VisitableNode> Statements()
{
/* Statements : Statement SEMI
* | Statement SEMI Statements
*/
VisitableNode node = Statement();
List <VisitableNode> results = new List <VisitableNode>();
results.Add(node);
while (this.currentToken.GetTokenValueType() == TokenValues.SEMI)
{
Eat(TokenValues.SEMI);
results.Add(Statement());
}
if (this.currentToken.GetTokenValueType() == TokenValues.ID)
{
throw new InterpreterException("Syntax error");
}
return(results);
}
public void addChild(VisitableNode c)
{
this.children.Add(c);
}