Changeset 15832 for branches/2886_SymRegGrammarEnumeration/HeuristicLab.Algorithms.DataAnalysis.SymRegGrammarEnumeration/GrammarEnumeration/Symbol.cs

Timestamp:

03/08/18 10:54:04 (7 years ago)

Author:

lkammere

Message:

#2886: Fix Equals methods in Symbols.
Move semantical hashing of phrases to separate class.

File:

• branches/2886_SymRegGrammarEnumeration/HeuristicLab.Algorithms.DataAnalysis.SymRegGrammarEnumeration/GrammarEnumeration/Symbol.cs (modified) (3 diffs)

branches/2886_SymRegGrammarEnumeration/HeuristicLab.Algorithms.DataAnalysis.SymRegGrammarEnumeration/GrammarEnumeration/Symbol.cs

@@ -20 +20 @@
     #region IEquatable
     public static bool operator ==(Symbol s1, Symbol s2) {
-      return !ReferenceEquals(null, s1) && !ReferenceEquals(null, s2) && (ReferenceEquals(s1, s2)
-        || s1.Equals(s2));
+      if (ReferenceEquals(s1, s2)) return true;
+      if (ReferenceEquals(s1, null) || ReferenceEquals(s2, null)) return false;
+      return s1.Equals(s2);
     }
 
@@ -29 +30 @@
 
     public bool Equals(Symbol other) {
-      if (ReferenceEquals(null, other)) return false;
-      if (ReferenceEquals(this, other)) return true;
-      return string.Equals(StringRepresentation, other.StringRepresentation);
+      if (ReferenceEquals(other, null)) return false;
+      if (ReferenceEquals(other, this)) return true;
+      if (this.GetType() != other.GetType()) return false; // Otherwise, this needs to be reimplemented in derived classes.
+      return StringRepresentation == other.StringRepresentation;
     }
 
     public override bool Equals(object obj) {
-      if (ReferenceEquals(null, obj)) return false;
-      if (ReferenceEquals(this, obj)) return true;
-      if (obj.GetType() != this.GetType()) return false;
+      if (ReferenceEquals(obj, null)) return false;
+      if (ReferenceEquals(obj, this)) return true;
+      if (this.GetType() != obj.GetType()) return false;
       return Equals((Symbol)obj);
     }
@@ -48 +50 @@
 
   public class TerminalSymbol : Symbol {
-    public readonly bool IsVariable;
 
-    public TerminalSymbol(string representation, bool isVariable = false) : base(representation) {
-      IsVariable = isVariable;
-    }
+    public TerminalSymbol(string representation) : base(representation) { }
   }
 
+  public class VariableTerminalSymbol : TerminalSymbol {
+    public VariableTerminalSymbol(string representation) : base(representation) { }
+  }
+
+
   public class NonterminalSymbol : Symbol {
-    public List<Production> Alternatives { get; }
+    private readonly List<Production> alternatives;
+
+    public IReadOnlyList<Production> Alternatives {
+      get { return alternatives.AsReadOnly(); }
+    }
 
     public NonterminalSymbol(string representation) : base(representation) {
-      Alternatives = new List<Production>();
+      alternatives = new List<Production>();
     }
 
     public void AddProduction(params Symbol[] production) {
-      Alternatives.Add(new Production(production));
+      alternatives.Add(new Production(production));
     }
   }
 
   public class VariableSymbol : NonterminalSymbol { // Convenience class
-    public IEnumerable<TerminalSymbol> VariableTerminalSymbols { get; }
+    public IEnumerable<VariableTerminalSymbol> VariableTerminalSymbols { get; }
 
     public VariableSymbol(string representation, IEnumerable<string> variableNames) : base(representation) {
-      List<TerminalSymbol> createdSymbols = new List<TerminalSymbol>();
+      List<VariableTerminalSymbol> createdSymbols = new List<VariableTerminalSymbol>();
       VariableTerminalSymbols = createdSymbols;
 
       foreach (string variableName in variableNames) {
-        TerminalSymbol s = new TerminalSymbol(variableName, isVariable: true);
+        VariableTerminalSymbol s = new VariableTerminalSymbol(variableName);
         createdSymbols.Add(s);
         AddProduction(s);