// The Nova Project by Ken Beckett.
// Copyright (C) 2007-2012 Inevitable Software, all rights reserved.
// Released under the Common Development and Distribution License, CDDL-1.0: http://opensource.org/licenses/cddl1.php
using Nova.Parsing;
using Nova.Resolving;
namespace Nova.CodeDOM
{
/// <summary>
/// Converts an <see cref="Expression"/> to the specified type, returning null if the conversion can't be done.
/// </summary>
public class As : BinaryOperator
{
#region /* CONSTRUCTORS */
/// <summary>
/// Create an <see cref="As"/> operator.
/// </summary>
public As(Expression left, Expression type)
: base(left, type)
{ }
#endregion
#region /* PROPERTIES */
/// <summary>
/// The symbol associated with the operator.
/// </summary>
public override string Symbol
{
get { return ParseToken; }
}
/// <summary>
/// True if the expression is const.
/// </summary>
public override bool IsConst
{
get { return false; }
}
#endregion
#region /* PARSING */
/// <summary>
/// The token used to parse the code object.
/// </summary>
public const string ParseToken = "as";
/// <summary>
/// The precedence of the operator.
/// </summary>
public const int Precedence = 330;
/// <summary>
/// True if the operator is left-associative, or false if it's right-associative.
/// </summary>
public const bool LeftAssociative = true;
internal static new void AddParsePoints()
{
Parser.AddOperatorParsePoint(ParseToken, Precedence, LeftAssociative, false, Parse);
}
/// <summary>
/// Parse an <see cref="As"/> operator.
/// </summary>
public static As Parse(Parser parser, CodeObject parent, ParseFlags flags)
{
return new As(parser, parent);
}
protected As(Parser parser, CodeObject parent)
: base(parser, parent)
{ }
/// <summary>
/// Get the precedence of the operator.
/// </summary>
public override int GetPrecedence()
{
return Precedence;
}
#endregion
#region /* RESOLVING */
/// <summary>
/// Resolve all child symbolic references, using the specified <see cref="ResolveCategory"/> and <see cref="ResolveFlags"/>.
/// </summary>
public override CodeObject Resolve(ResolveCategory resolveCategory, ResolveFlags flags)
{
// Override the base-class behavior so that we can resolve the right side as a Type
// instead of an Expression (avoiding matches on Property names, for example).
if (_left != null)
_left = (Expression)_left.Resolve(ResolveCategory.Expression, flags);
if (_right != null)
_right = (Expression)_right.Resolve(ResolveCategory.Type, flags);
return this;
}
/// <summary>
/// Evaluate the type of the <see cref="Expression"/>.
/// </summary>
/// <returns>The resulting <see cref="TypeRef"/> or <see cref="UnresolvedRef"/>.</returns>
public override TypeRefBase EvaluateType(bool withoutConstants)
{
// Evaluate to the type specified by the Right expression
return _right.EvaluateType(withoutConstants);
}
#endregion
}
}