public object VisitWhileStmt(Stmt.While stmt)
{
Resolve(stmt.condition);
Resolve(stmt.body);
return(null);
}
// our first desugaring
private Stmt ForStatement()
{
loopDepth++;
try
{
Consume(Token.TokenType.LeftParenthesis, "Expect '(' after 'for'.");
Stmt initializer;
if (Match(Token.TokenType.Semicolon))
{
initializer = null;
}
else if (Match(Token.TokenType.Var))
{
initializer = VarDeclaration();
}
else
{
initializer = ExpressionStatement();
}
Expr condition = null;
if (!Check(Token.TokenType.Semicolon))
{
condition = Expression();
}
Consume(Token.TokenType.Semicolon, "Expect ';' after loop condition.");
Expr increment = null;
if (!Check(Token.TokenType.RightParenthesis))
{
increment = Expression();
}
Consume(Token.TokenType.RightParenthesis, "Expect ')' after for clauses.");
Stmt body = Statement();
if (increment != null)
{
body = new Stmt.Block(
new List <Stmt>()
{
body,
new Stmt.Expression(increment)
}
);
}
if (condition == null)
{
condition = new Expr.Literal(true);
}
body = new Stmt.While(condition, body);
if (initializer != null)
{
body = new Stmt.Block(
new List <Stmt>()
{
initializer,
body
}
);
}
return(body);
}
finally
{
loopDepth--;
}
}