ILSpy/ICSharpCode.Decompiler/CSharp/Syntax/SyntaxExtensions.cs

// Copyright (c) 2013 Daniel Grunwald
// 
// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the "Software"), to deal
// in the Software without restriction, including without limitation the rights
// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
// copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions:
// 
// The above copyright notice and this permission notice shall be included in
// all copies or substantial portions of the Software.
// 
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
// THE SOFTWARE.

#nullable enable

namespace ICSharpCode.Decompiler.CSharp.Syntax
{
	/// <summary>
	/// Extension methods for the syntax tree.
	/// </summary>
	public static class SyntaxExtensions
	{
		public static bool IsComparisonOperator(this OperatorType operatorType)
		{
			switch (operatorType)
			{
				case OperatorType.Equality:
				case OperatorType.Inequality:
				case OperatorType.GreaterThan:
				case OperatorType.LessThan:
				case OperatorType.GreaterThanOrEqual:
				case OperatorType.LessThanOrEqual:
					return true;
				default:
					return false;
			}
		}

		/// <summary>
		/// Returns true if <paramref name="operatorType"/> is bitwise and, bitwise or, or exclusive or.
		/// </summary>
		public static bool IsBitwise(this BinaryOperatorType operatorType)
		{
			return operatorType == BinaryOperatorType.BitwiseAnd
				|| operatorType == BinaryOperatorType.BitwiseOr
				|| operatorType == BinaryOperatorType.ExclusiveOr;
		}

		public static Statement? GetNextStatement(this Statement statement)
		{
			AstNode? next = statement.NextSibling;
			while (next != null && !(next is Statement))
				next = next.NextSibling;
			return (Statement?)next;
		}

		/// <summary>
		/// The first statement of <paramref name="statements"/> that is not an
		/// <see cref="EmptyStatement"/>, or <c>null</c> if there is none.
		/// </summary>
		/// <remarks>
		/// An empty statement is either a stray ';' or a placeholder carrying a comment the
		/// decompiler emitted (a warning, an unconvertible block, a "try-fault" marker, ...).
		/// Neither is a statement in the sense a transform matching a statement sequence means,
		/// so every such transform has to look past them or it silently stops recognizing its
		/// pattern as soon as one of those comments lands in the middle of the sequence.
		/// </remarks>
		public static Statement? GetFirstNonEmptyStatementOrDefault(this AstNodeCollection<Statement> statements)
		{
			return statements.FirstOrNull(statement => statement is not EmptyStatement);
		}

		/// <summary>
		/// The next statement after <paramref name="statement"/> that is not an
		/// <see cref="EmptyStatement"/>, or <c>null</c> if there is none.
		/// </summary>
		/// <remarks>
		/// See <see cref="GetFirstNonEmptyStatementOrDefault"/> for why the skip is needed.
		/// </remarks>
		public static Statement? GetNextNonEmptyStatement(this Statement statement)
		{
			var next = statement.GetNextStatement();
			while (next is EmptyStatement)
				next = next.GetNextStatement();
			return next;
		}

		public static bool IsArgList(this AstType? type)
		{
			var simpleType = type as SimpleType;
			return simpleType != null && simpleType.Identifier == "__arglist";
		}

		public static void AddNamedArgument(this Syntax.Attribute attribute, string name, Expression argument)
		{
			attribute.Arguments.Add(new AssignmentExpression(new IdentifierExpression(name), argument));
		}

		public static T Detach<T>(this T node) where T : AstNode
		{
			node.Remove();
			return node;
		}

		public static Expression UnwrapInDirectionExpression(this Expression expr)
		{
			if (!(expr is DirectionExpression dir && dir.FieldDirection == FieldDirection.In))
				return expr;
			return dir.Expression.Detach();
		}
	}
}