Feature: Golf function, variable and #define names.

Author: DeanEdisGG

README.md

@@ -21,17 +21,15 @@ After writing a Shadertoy shader, usually from my boilerplate starting code, the
 
 It occurred to me all of these steps can be automated.
 
-## What Is It *Not* For?
-This is *not* a tool to compete with certain other tools to absolutely MINIMIZE the size of the code - Useful for preparing GLSL for use in 4KB graphics demos, etc.
+## What It *Can* Do
+Over time more and more functionality has been added to this tool which can be used to '[GOLF](https://en.wikipedia.org/wiki/Code_golf)' code.
+This is an ongoing process, and other tools are much more likely to produce more compact/compressible code (Especially when preparing GLSL for use in 4KB graphics demos, etc). However, GLSL Shader Shrinker can... 
 
-GLSL Shader Shrink will _not_:
 * Rename functions and variable to single-characters.
 * Inline functions.
 * Introduce ```#define``` macros to minimize the code character count.
-* Replace code with a 'more compressible' equivalent.
-* ...or otherwise '[GOLF](https://en.wikipedia.org/wiki/Code_golf)' anything.
 
-...although some of these items might be suggested as a 'hint'.
+(Some of of these items might be suggested as a 'hint' even when not GOLFing.)
 
 ## Example (Shadertoy Starting Point)
 A small snippet of GLSL which shows **some** of the optimizations available.
@@ -90,7 +88,7 @@ Next choose the level of processing you want to apply.
 
 * Maximum processing - All options enabled.
 * Minimal processing - Minimal changes (Mostly code reformatting).
-* Custom options - Toggle exactly which processing features you require.
+* Custom options - Toggle exactly which processing features you require (Including GOLFing options)
 
 ### Step 3 - Exporting GLSL Code
 Export the 'shrunk' GLSL.
@@ -146,6 +144,7 @@ In most cases they can be worked-around using a set of 'custom' settings which d
 * [Perform Simple Arithmetic](#perform-simple-arithmetic)
 * [Replace Functions Calls With Result](#replace-functions-calls-with-result)
 * [Move constant parameters to within called functions](#move-constant-parameters-to-within-called-functions)
+* [GOLF user defined code names](#golf-user-defined-code-names)
 ## Remove Comments
 Remove all C/C++ -style comments from the code.
 #### Before
@@ -614,3 +613,20 @@ float f() {
 ```
 
 ---
+## GOLF user defined code names
+Reduce the size of the code by renaming user-defined names.
+Attempts are made to keep some of the letters of the object to rename.
+#### Before
+```c
+float sum(float number, float anotherNumber) {
+    return number + anotherNumber;
+}
+```
+#### After
+```c
+float s(float n, float a) {
+    return n + a;
+}
+```
+
+---

ShaderShrinker/Shrinker.Lexer/StringExtensions.cs

@@ -43,31 +43,7 @@ public static int GetCodeCharCount(this string glsl)
                     glsl = glsl.Remove(startComment, endComment - startComment + 2);
             }
 
-            return glsl.Split('\r', '\n').Sum(o => o.GetCodeCharCountForLine());
-        }
-
-        private static int GetCodeCharCountForLine(this string line)
-        {
-            return line.Count(ch => !char.IsWhiteSpace(ch));
-            //var commentIndex = line.IndexOf("//");
-            //if (commentIndex >= 0)
-            //    line = line.Substring(0, commentIndex);
-            //commentIndex = line.IndexOf("/*");
-            //if (commentIndex >= 0)
-            //    line = line.Substring(0, commentIndex);
-
-            //var sb = new StringBuilder(line.Trim());
-            //int l;
-            //do
-            //{
-            //    l = sb.Length;
-            //    sb.Replace(" ", null)
-            //      .Replace("\t", null)
-            //      .Replace("\r", null)
-            //      .Replace("\n", null);
-            //} while (sb.Length != l);
-
-            //return sb.Length;
+            return glsl.Split('\r', '\n').Sum(o => o.Count(ch => !char.IsWhiteSpace(ch)));
         }
 
         public static bool IsNewline(this char ch) => ch == '\n' || ch == '\r';

ShaderShrinker/Shrinker.Parser/CustomOptions.cs

@@ -47,6 +47,7 @@ public class CustomOptions
         public bool SimplifyBranching { get; set; }
         public bool ReplaceFunctionCallsWithResult { get; set; }
         public bool MoveConstantParametersIntoCalledFunctions { get; set; }
+        public bool GolfNames { get; set; }
 
         private CustomOptions()
         {
@@ -56,12 +57,13 @@ public static CustomOptions All()
         {
             var options = SetAllOptions(true);
             options.KeepHeaderComments = false;
+            options.GolfNames = false;
             return options;
         }
 
         public static CustomOptions None() => SetAllOptions(false);
 
-        private static CustomOptions SetAllOptions(bool value)
+        public static CustomOptions SetAllOptions(bool value)
         {
             var options = new CustomOptions();
 

ShaderShrinker/Shrinker.Parser/Optimizations/GolfExtensions.cs

@@ -0,0 +1,94 @@
+// -----------------------------------------------------------------------
+//  <copyright file="GolfExtensions.cs">
+//      Copyright (c) 2022 Dean Edis. All rights reserved.
+//  </copyright>
+//  <summary>
+//  This code is provided on an "as is" basis and without warranty of any kind.
+//  We do not warrant or make any representations regarding the use or
+//  results of use of this code.
+//  </summary>
+// -----------------------------------------------------------------------
+
+using System.Collections.Generic;
+using System.Linq;
+using Shrinker.Parser.SyntaxNodes;
+
+namespace Shrinker.Parser.Optimizations
+{
+    public static class GolfExtensions
+    {
+        /// <summary>
+        /// Replace named objects (functions/variables) with short 'golfed' versions.
+        /// </summary>
+        public static void GolfNames(this SyntaxNode rootNode)
+        {
+            var nameMap = BuildGolfRenameMap(rootNode).Where(o => o.Key != o.Value).ToDictionary(o => o.Key, o => o.Value);
+
+            foreach (var node in rootNode.TheTree.OfType<IRenamable>().Where(o => nameMap.ContainsKey(NameWithoutDotSuffix(o.Name))).ToList())
+            {
+                if (!((SyntaxNode)node).HasAncestor<StructDefinitionSyntaxNode>())
+                    node.Rename(nameMap[NameWithoutDotSuffix(node.Name)]);
+            }
+        }
+
+        private static string NameWithoutDotSuffix(string name) => name.Split('.').First();
+
+        private static Dictionary<string, string> BuildGolfRenameMap(SyntaxNode rootNode)
+        {
+            var originalNames = rootNode.FindUserDefinedNames();
+            var nameMap = originalNames.ToDictionary(o => o, o => o);
+
+            foreach (var kvp in nameMap.Where(o => o.Value.Length > 1))
+            {
+                // Try to abbreviate to one letter.
+                var candidate = $"{kvp.Value.First()}";
+
+                const string Letters = "abcdefghijlkmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ";
+                if (nameMap.ContainsValue(candidate))
+                {
+                    // Name is used - Assign unused single-letter.
+                    var ch = Letters.FirstOrDefault(o => !nameMap.ContainsValue($"{o}"));
+                    if (ch != 0)
+                        candidate = $"{ch}";
+                }
+
+                if (nameMap.ContainsValue(candidate))
+                {
+                    // Name is used - Concatenate first and last characters.
+                    candidate = $"{kvp.Value.First()}{kvp.Value.Last()}";
+                }
+
+                if (nameMap.ContainsValue(candidate))
+                {
+                    // Name is used - Try upper case.
+                    candidate = candidate.ToUpper();
+                }
+
+                if (nameMap.ContainsValue(candidate))
+                {
+                    // Name is used - Try lower case.
+                    candidate = candidate.ToLower();
+                }
+
+                var n = 0;
+                while (nameMap.ContainsValue(candidate))
+                {
+                    // Name is used - Try letter and number.
+                    foreach (var ch in Letters)
+                    {
+                        candidate = $"{ch}{n}";
+                        if (!nameMap.ContainsValue(candidate))
+                            break;
+                    }
+
+                    n++;
+                }
+
+                // Update the map.
+                nameMap[kvp.Key] = $"{candidate}";
+            }
+
+            return nameMap;
+        }
+    }
+}

ShaderShrinker/Shrinker.Parser/Shrinker.cs

@@ -107,6 +107,9 @@ public static SyntaxNode Simplify(this SyntaxNode rootNode, CustomOptions option
                     repeatSimplifications |= rootNode.MoveConstantParametersIntoCalledFunctions();
             }
 
+            if (options.GolfNames)
+                rootNode.GolfNames();
+
             return rootNode;
         }
     }

ShaderShrinker/Shrinker.Parser/SyntaxNodes/FunctionCallSyntaxNode.cs

@@ -17,9 +17,10 @@ namespace Shrinker.Parser.SyntaxNodes
     /// <summary>
     /// Represents a user-defined function.
     /// </summary>
-    public class FunctionCallSyntaxNode : SyntaxNode
+    public class FunctionCallSyntaxNode : SyntaxNode, IRenamable
     {
-        public string Name { get; }
+        public string Name { get; private set; }
+
         public RoundBracketSyntaxNode Params => (RoundBracketSyntaxNode)Children[0];
 
         public FunctionCallSyntaxNode(GenericSyntaxNode nameNode, RoundBracketSyntaxNode brackets) : this(nameNode?.Token?.Content)
@@ -45,5 +46,10 @@ private FunctionCallSyntaxNode(string name)
         /// </summary>
         public FunctionDefinitionSyntaxNode GetCallee() =>
             this.Root().FunctionDefinitions().FirstOrDefault(o => o.Name == Name && Params.GetCsv().Count() == o.Params.GetCsv().Count());
+
+        public void Rename(string newName)
+        {
+            Name = newName;
+        }
     }
 }

ShaderShrinker/Shrinker.Parser/SyntaxNodes/FunctionSyntaxNodeBase.cs

@@ -15,7 +15,7 @@
 
 namespace Shrinker.Parser.SyntaxNodes
 {
-    public abstract class FunctionSyntaxNodeBase : SyntaxNode
+    public abstract class FunctionSyntaxNodeBase : SyntaxNode, IRenamable
     {
         public string ReturnType { get; protected set; }
         public string Name => Children[0].Token.Content;
@@ -37,5 +37,7 @@ public List<GenericSyntaxNode> ParamNames
         }
 
         public bool IsMain() => Name.StartsWith("main");
+
+        public void Rename(string newName) => Children[0].ReplaceWith(new GenericSyntaxNode(newName));
     }
 }

ShaderShrinker/Shrinker.Parser/SyntaxNodes/GenericSyntaxNode.cs

@@ -14,7 +14,7 @@
 
 namespace Shrinker.Parser.SyntaxNodes
 {
-    public class GenericSyntaxNode : SyntaxNode
+    public class GenericSyntaxNode : SyntaxNode, IRenamable
     {
         public GenericSyntaxNode(IToken token) : base(token)
         {
@@ -31,14 +31,13 @@ public GenericSyntaxNode(string s) : base(new AlphaNumToken(s))
         /// </summary>
         public VariableDeclarationSyntaxNode FindVarDeclaration()
         {
-            var varName = Token.Content.Split('.').First();
             var node = (SyntaxNode)this;
 
             while (node != null)
             {
                 var decl = node.Parent?.Children
                     .OfType<VariableDeclarationSyntaxNode>()
-                    .FirstOrDefault(o => o.IsDeclared(varName));
+                    .FirstOrDefault(o => o.IsDeclared(Name));
                 if (decl != null)
                     return decl;
 
@@ -52,5 +51,18 @@ public VariableDeclarationSyntaxNode FindVarDeclaration()
         public bool IsVarName(string varName) => this.HasNodeContent(varName);
 
         protected override SyntaxNode CreateSelf() => new GenericSyntaxNode(Token.Clone());
+
+        public string Name => Token.Content.Split('.').First();
+
+        public void Rename(string newName)
+        {
+            if (Token.Content.Contains('.'))
+            {
+                // Looks like a variable name referencing a named element. (E.g. foo.x) - Rename the prefix only.
+                newName += Token.Content.Substring(Name.Length);
+            }
+
+            Token = new AlphaNumToken(newName);
+        }
     }
 }

ShaderShrinker/Shrinker.Parser/SyntaxNodes/IRenamable.cs

@@ -0,0 +1,19 @@
+// -----------------------------------------------------------------------
+//  <copyright file="IRenamable.cs">
+//      Copyright (c) 2021 Dean Edis. (Twitter: @deanthecoder) All rights reserved.
+//  </copyright>
+//  <summary>
+//  This code is provided on an "as is" basis and without warranty of any kind.
+//  We do not warrant or make any representations regarding the use or
+//  results of use of this code.
+//  </summary>
+// -----------------------------------------------------------------------
+
+namespace Shrinker.Parser.SyntaxNodes;
+
+public interface IRenamable
+{
+    string Name { get; }
+
+    void Rename(string newName);
+}

ShaderShrinker/Shrinker.Parser/SyntaxNodes/SyntaxNode.cs

@@ -69,7 +69,7 @@ public IEnumerable<SyntaxNode> SelfAndNextSiblings
 
         public IEnumerable<SyntaxNode> NextSiblings => SelfAndNextSiblings.Skip(1);
 
-        public IToken Token { get; }
+        public IToken Token { get; protected set; }
 
         public IReadOnlyList<SyntaxNode> Children => m_children;