Fix: Avoid spurious code changes during 'shrink'.

Cloning a node would copy, not clone, its token. If later that token is modified, clones of the token would be modified too.
Most noticeable when inlining a constant into multiple locations, then trying to modify one of them.

Author: DeanEdisGG

ShaderShrinker/Shrinker.Lexer/AlphaNumToken.cs

@@ -45,5 +45,7 @@ public override IToken TryMatch(string code, ref int offset)
 
             return new AlphaNumToken(Read(code, ref offset, s.Length));
         }
+
+        public override IToken Clone() => new AlphaNumToken(Content);
     }
 }

ShaderShrinker/Shrinker.Lexer/AssignmentOperatorToken.cs

@@ -4,5 +4,7 @@ public class AssignmentOperatorToken : Token
     {
         public override IToken TryMatch(string code, ref int offset) =>
             Peek(code, offset) == '=' ? new AssignmentOperatorToken { Content = Read(code, ref offset) } : null;
+
+        public override IToken Clone() => new AssignmentOperatorToken { Content = Content };
     }
 }

ShaderShrinker/Shrinker.Lexer/BackslashToken.cs

@@ -20,5 +20,7 @@ public BackslashToken()
 
         public override IToken TryMatch(string code, ref int offset) =>
             Peek(code, offset) == '\\' ? new BackslashToken { Content = Read(code, ref offset) } : null;
+
+        public override IToken Clone() => new BackslashToken();
     }
 }

ShaderShrinker/Shrinker.Lexer/BracketToken.cs

@@ -4,5 +4,7 @@ public class BracketToken : Token
     {
         public override IToken TryMatch(string code, ref int offset) =>
             "(){}[]".Contains(Peek(code, offset, 1)) ? new BracketToken { Content = Read(code, ref offset) } : null;
+
+        public override IToken Clone() => new BracketToken { Content = Content };
     }
 }

ShaderShrinker/Shrinker.Lexer/CommaToken.cs

@@ -20,5 +20,7 @@ public CommaToken()
 
         public override IToken TryMatch(string code, ref int offset) =>
             Peek(code, offset) == ',' ? new CommaToken { Content = Read(code, ref offset) } : null;
+
+        public override IToken Clone() => new CommaToken();
     }
 }

ShaderShrinker/Shrinker.Lexer/ConstToken.cs

@@ -44,5 +44,7 @@ public override IToken TryJoin(List<IToken> tokens, int tokenIndex, out int dele
             deleteTotal = count + 1;
             return tokens[tokenIndex + count];
         }
+
+        public override IToken Clone() => new ConstToken { Content = Content };
     }
 }

ShaderShrinker/Shrinker.Lexer/DotToken.cs

@@ -48,5 +48,7 @@ public override IToken TryJoin(List<IToken> tokens, int tokenIndex, out int dele
 
             return deleteTotal <= 1 ? null : new FloatToken(newContent.ToString());
         }
+
+        public override IToken Clone() => new DotToken { Content = "." };
     }
 }

ShaderShrinker/Shrinker.Lexer/EqualityOperatorToken.cs

@@ -4,5 +4,7 @@ public class EqualityOperatorToken : Token
     {
         public override IToken TryMatch(string code, ref int offset) =>
             Peek(code, offset, 2) == "==" ? new EqualityOperatorToken { Content = Read(code, ref offset, 2) } : null;
+
+        public override IToken Clone() => new EqualityOperatorToken { Content = "==" };
     }
 }

ShaderShrinker/Shrinker.Lexer/FloatToken.cs

@@ -32,6 +32,8 @@ public FloatToken(string s)
         public override IToken TryMatch(string code, ref int offset) =>
             throw new InvalidOperationException("Should be created by DotToken.");
 
+        public override IToken Clone() => new FloatToken(Content);
+
         public IToken Simplify()
         {
             const int MaxSigFigs = 9;

ShaderShrinker/Shrinker.Lexer/IToken.cs

@@ -26,5 +26,7 @@ public interface IToken
         /// Post-process the complete token list, allowing a token to merge with its neighbors. (E.g. '//' merging with following text until newline.
         /// </summary>
         IToken TryJoin(List<IToken> tokens, int tokenIndex, out int deletePrevious, out int deleteTotal);
+
+        IToken Clone();
     }
 }