Resolving Symbolic References in a CodeDOM (Part 7)

// 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 System;

using Nova.Parsing;
using Nova.Rendering;
using Nova.Resolving;

namespace Nova.CodeDOM
{
    /// <summary>
    /// Indicates that an exception should be thrown, and has an expression that should evaluate
    /// to an object of type <see cref="Exception"/>.  If the expression is omitted (null), then any
    /// currently active exception (inside a <see cref="Catch"/> body) is re-thrown.
    /// </summary>
    public class Throw : Statement
    {
        #region /* FIELDS */

        protected Expression _expression;

        #endregion

        #region /* CONSTRUCTORS */

        /// <summary>
        /// Create a <see cref="Throw"/>.
        /// </summary>
        public Throw(Expression expression)
        {
            Expression = expression;
        }

        /// <summary>
        /// Create a <see cref="Throw"/>.
        /// </summary>
        public Throw()
        { }

        #endregion

        #region /* PROPERTIES */

        /// <summary>
        /// The optional exception <see cref="Expression"/>.
        /// </summary>
        public Expression Expression
        {
            get { return _expression; }
            set { SetField(ref _expression, value, true); }
        }

        /// <summary>
        /// The keyword associated with the <see cref="Statement"/>.
        /// </summary>
        public override string Keyword
        {
            get { return ParseToken; }
        }

        #endregion

        #region /* METHODS */

        /// <summary>
        /// Deep-clone the code object.
        /// </summary>
        public override CodeObject Clone()
        {
            Throw clone = (Throw)base.Clone();
            clone.CloneField(ref clone._expression, _expression);
            return clone;
        }

        #endregion

        #region /* PARSING */

        /// <summary>
        /// The token used to parse the code object.
        /// </summary>
        public const string ParseToken = "throw";

        internal static void AddParsePoints()
        {
            Parser.AddParsePoint(ParseToken, Parse, typeof(IBlock));
        }

        /// <summary>
        /// Parse a <see cref="Throw"/>.
        /// </summary>
        public static Throw Parse(Parser parser, CodeObject parent, ParseFlags flags)
        {
            return new Throw(parser, parent);
        }

        protected Throw(Parser parser, CodeObject parent)
            : base(parser, parent)
        {
            parser.NextToken();  // Move past 'throw'
            SetField(ref _expression, Expression.Parse(parser, this, true), false);
            ParseTerminator(parser);
        }

        #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)
        {
            if (_expression != null)
                _expression = (Expression)_expression.Resolve(ResolveCategory.Expression, flags);
            return this;
        }

        /// <summary>
        /// Returns true if the code object is an <see cref="UnresolvedRef"/> or has any <see cref="UnresolvedRef"/> children.
        /// </summary>
        public override bool HasUnresolvedRef()
        {
            if (_expression != null && _expression.HasUnresolvedRef())
                return true;
            return base.HasUnresolvedRef();
        }

        #endregion

        #region /* FORMATTING */

        /// <summary>
        /// True if the <see cref="Statement"/> has an argument.
        /// </summary>
        public override bool HasArgument
        {
            get { return (_expression != null); }
        }

        /// <summary>
        /// True if the <see cref="Statement"/> has parens around its argument.
        /// </summary>
        public override bool HasArgumentParens
        {
            get { return false; }
        }

        /// <summary>
        /// True if the <see cref="Statement"/> has a terminator character by default.
        /// </summary>
        public override bool HasTerminatorDefault
        {
            get { return true; }
        }

        /// <summary>
        /// Determines if the code object only requires a single line for display.
        /// </summary>
        public override bool IsSingleLine
        {
            get { return (base.IsSingleLine && (_expression == null || (!_expression.IsFirstOnLine && _expression.IsSingleLine))); }
            set
            {
                base.IsSingleLine = value;
                if (value && _expression != null)
                {
                    _expression.IsFirstOnLine = false;
                    _expression.IsSingleLine = true;
                }
            }
        }

        #endregion

        #region /* RENDERING */

        protected override void AsTextArgument(CodeWriter writer, RenderFlags flags)
        {
            if (_expression != null)
                _expression.AsText(writer, flags);
        }

        #endregion
    }
}