public ForStatement(DeclareNode initialDeclaration, ExpressionNode condition, ExpressionNode iteration, StatementNode statement)
{
InitialDeclaration = initialDeclaration;
Condition = condition;
Iteration = iteration;
Statement = statement;
}
private StatementNode ParseStatement()
{
// Return statement
if (TryTakeFixedToken(FixedToken.Kind.Return))
{
// Expression to return
var expression = ParseExpression();
// Semi colon
TakeFixedToken(FixedToken.Kind.SemiColon);
return(new ReturnNode(expression));
}
// If statement
else if (TryTakeFixedToken(FixedToken.Kind.If))
{
// ( expr )
TakeFixedToken(FixedToken.Kind.ParOpen);
var conditional = ParseExpression();
TakeFixedToken(FixedToken.Kind.ParClose);
// True statement
var trueStatement = ParseStatement();
// Optional else + statement
StatementNode falseStatement = null;
if (TryTakeFixedToken(FixedToken.Kind.Else))
{
falseStatement = ParseStatement();
}
return(new IfStatmentNode(conditional, trueStatement, falseStatement));
}
// Block statement
else if (TryTakeFixedToken(FixedToken.Kind.BracketOpen))
{
// Parse statements until we find (and take!) a closing bracket after one
var blockItems = new List <BlockItemNode>();
while (!TryTakeFixedToken(FixedToken.Kind.BracketClose))
{
var statement = ParseBlockItem();
blockItems.Add(statement);
}
;
return(new BlockStatementNode(blockItems));
}
// Break and continue
else if (TryTakeFixedToken(FixedToken.Kind.Break))
{
TakeFixedToken(FixedToken.Kind.SemiColon);
return(new BreakStatement());
}
else if (TryTakeFixedToken(FixedToken.Kind.Continue))
{
TakeFixedToken(FixedToken.Kind.SemiColon);
return(new ContinueStatement());
}
// While statement
else if (TryTakeFixedToken(FixedToken.Kind.While))
{
// while ( expr ) statement
TakeFixedToken(FixedToken.Kind.ParOpen);
var expr = ParseExpression();
TakeFixedToken(FixedToken.Kind.ParClose);
var statement = ParseStatement();
return(new WhileStatement(expr, statement));
}
// Do while statement
else if (TryTakeFixedToken(FixedToken.Kind.Do))
{
// do statement while expr ;
var statement = ParseStatement();
TakeFixedToken(FixedToken.Kind.While);
var expr = ParseExpression();
TakeFixedToken(FixedToken.Kind.SemiColon);
return(new DoWhileStatement(expr, statement));
}
// For statement
else if (TryTakeFixedToken(FixedToken.Kind.For))
{
// We have two options
// for ( decl opt-exp ; opt-exp ) statement
// for ( opt-exp ; opt-exp ; opt-exp ) statement
DeclareNode initialDeclare = null;
ExpressionNode initialExpr = null;
TakeFixedToken(FixedToken.Kind.ParOpen);
// TODO: Support for other types
if (PeekFixedToken(FixedToken.Kind.Int))
{
// decl
initialDeclare = ParseDeclaration();
}
else
{
// opt-exp ;
initialExpr = ParseOptionalExpression();
TakeFixedToken(FixedToken.Kind.SemiColon);
}
var conditionExpr = ParseOptionalExpression();
TakeFixedToken(FixedToken.Kind.SemiColon);
var iterationExpr = ParseOptionalExpression();
TakeFixedToken(FixedToken.Kind.ParClose);
var statement = ParseStatement();
// Condition expression must be replaced with a non-zero constant if it's missing
if (conditionExpr == null)
{
conditionExpr = s_constOneNode;
}
if (initialDeclare != null)
{
return(new ForStatement(initialDeclare, conditionExpr, iterationExpr, statement));
}
return(new ForStatement(initialExpr, conditionExpr, iterationExpr, statement));
}
// Treat it as an expression statement
return(ParseExpressionStatement());
}