antlr/Antlr4.Runtime/Atn/Transition.cs

/*
 * [The "BSD license"]
 *  Copyright (c) 2013 Terence Parr
 *  Copyright (c) 2013 Sam Harwell
 *  All rights reserved.
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using System;
using System.Collections.Generic;
using Antlr4.Runtime.Atn;
using Antlr4.Runtime.Misc;
using Sharpen;

namespace Antlr4.Runtime.Atn
{
	/// <summary>An ATN transition between any two ATN states.</summary>
	/// <remarks>
	/// An ATN transition between any two ATN states.  Subclasses define
	/// atom, set, epsilon, action, predicate, rule transitions.
	/// <p/>
	/// This is a one way link.  It emanates from a state (usually via a list of
	/// transitions) and has a target state.
	/// <p/>
	/// Since we never have to change the ATN transitions once we construct it,
	/// we can fix these transitions as specific classes. The DFA transitions
	/// on the other hand need to update the labels as it adds transitions to
	/// the states. We'll use the term Edge for the DFA to distinguish them from
	/// ATN transitions.
	/// </remarks>
	public abstract class Transition
	{
		public const int Epsilon = 1;

		public const int Range = 2;

		public const int Rule = 3;

		public const int Predicate = 4;

		public const int Atom = 5;

		public const int Action = 6;

		public const int Set = 7;

		public const int NotSet = 8;

		public const int Wildcard = 9;

		public const int Precedence = 10;

		public static readonly IList<string> serializationNames = Sharpen.Collections.UnmodifiableList
			(Arrays.AsList("INVALID", "EPSILON", "RANGE", "RULE", "PREDICATE", "ATOM", "ACTION"
			, "SET", "NOT_SET", "WILDCARD", "PRECEDENCE"));

		private sealed class _Dictionary_86 : Dictionary<Type, int>
		{
			public _Dictionary_86()
			{
				{
					// constants for serialization
					// e.g., {isType(input.LT(1))}?
					// ~(A|B) or ~atom, wildcard, which convert to next 2
					this.Put(typeof(EpsilonTransition), Antlr4.Runtime.Atn.Transition.Epsilon);
					this.Put(typeof(RangeTransition), Antlr4.Runtime.Atn.Transition.Range);
					this.Put(typeof(RuleTransition), Antlr4.Runtime.Atn.Transition.Rule);
					this.Put(typeof(PredicateTransition), Antlr4.Runtime.Atn.Transition.Predicate);
					this.Put(typeof(AtomTransition), Antlr4.Runtime.Atn.Transition.Atom);
					this.Put(typeof(ActionTransition), Antlr4.Runtime.Atn.Transition.Action);
					this.Put(typeof(SetTransition), Antlr4.Runtime.Atn.Transition.Set);
					this.Put(typeof(NotSetTransition), Antlr4.Runtime.Atn.Transition.NotSet);
					this.Put(typeof(WildcardTransition), Antlr4.Runtime.Atn.Transition.Wildcard);
					this.Put(typeof(PrecedencePredicateTransition), Antlr4.Runtime.Atn.Transition.Precedence
						);
				}
			}
		}

		public static readonly IDictionary<Type, int> serializationTypes = Sharpen.Collections
			.UnmodifiableMap(new _Dictionary_86());

		/// <summary>The target of this transition.</summary>
		/// <remarks>The target of this transition.</remarks>
		[NotNull]
		public ATNState target;

		protected internal Transition(ATNState target)
		{
			if (target == null)
			{
				throw new ArgumentNullException("target cannot be null.");
			}
			this.target = target;
		}

		public abstract int GetSerializationType();

		/// <summary>Are we epsilon, action, sempred?</summary>
		public virtual bool IsEpsilon()
		{
			return false;
		}

		[Nullable]
		public virtual IntervalSet Label()
		{
			return null;
		}

		public abstract bool Matches(int symbol, int minVocabSymbol, int maxVocabSymbol);
	}
}