feat: Better Precedence Handling

Source/Samples/Sample.FuncLanguage/ExpressionGrammar.cs

@@ -20,7 +20,7 @@ protected override void InitParselets()
         AddCommonLiterals();
         AddArithmeticOperators();
 
-        Register("(", new CallParselet(BindingPowers.Get("Call")));
+        Register("(", new CallParselet(PrecedenceLevels.Get("Call")));
         Register("(", new TupleOrGroupParselet());
 
         Register(PredefinedSymbols.Name, new NameParselet());

Source/Silverfly.Testing/SnapshotParserTestBase.cs

@@ -1,3 +1,5 @@
+using System.Reflection;
+using System.Runtime.CompilerServices;
 using Argon;
 using Silverfly.Testing.Converter;
 using static VerifyTests.VerifierSettings;

Source/Silverfly/DefaultPrecedenceLevels.cs

@@ -0,0 +1,25 @@
+namespace Silverfly;
+
+public class DefaultPrecedenceLevels : PrecedenceLevels
+{
+    public static string Assignment = nameof(Assignment);
+    public static string Conditional = nameof(Conditional);
+    public static string Sum = nameof(Sum);
+    public static string Product = nameof(Sum);
+    public static string Exponent = nameof(Exponent);
+    public static string Prefix = nameof(Prefix);
+    public static string PostFix = nameof(PostFix);
+    public static string Call = nameof(Call);
+
+    public DefaultPrecedenceLevels()
+    {
+        AddPrecedence(Assignment);
+        AddPrecedence(Conditional);
+        AddPrecedence(Sum);
+        AddPrecedence(Product);
+        AddPrecedence(Exponent);
+        AddPrecedence(Prefix);
+        AddPrecedence(PostFix);
+        AddPrecedence(Call);
+    }
+}

Source/Silverfly/Parser.cs

@@ -15,7 +15,7 @@ public abstract partial class Parser
     private readonly List<Token> _read = [];
     private Lexer _lexer;
 
-    public SymbolPool BindingPowers { get; internal set; }
+    public PrecedenceLevels PrecedenceLevels = new DefaultPrecedenceLevels();
 
     public SourceDocument Document => _lexer.Document;
 
@@ -91,11 +91,6 @@ public static TranslationUnit Parse<TParser>(string source, string filename = "s
 
         var parser = new TParser { _lexer = lexer };
 
-        var bindingPowerBuilder = new BindingPowerBuilder();
-
-        parser.InitBindingPower(bindingPowerBuilder); // Have to be initialized before parselets to allow named reference
-        parser.BindingPowers = bindingPowerBuilder.BuildPool();
-
         parser.InitParselets();
 
         AddLexerSymbols(lexer, parser._prefixParselets);
@@ -164,19 +159,6 @@ public AstNode ParseExpression()
     protected abstract void InitLexer(Lexer lexer);
     protected abstract void InitParselets();
 
-    protected virtual void InitBindingPower(BindingPowerBuilder precedence)
-    {
-        precedence
-            .StrongerThan("Exponent", "Product")
-            .StrongerThan("Product", "Sum")
-            .StrongerThan("Sum", "Conditional")
-            .StrongerThan("Conditional", "Assignment")
-            .StrongerThan("Prefix", "Exponent")
-            .StrongerThan("Postfix", "Call")
-            .StrongerThan("Prefix", "Postfix")
-            .StrongerThan("Prefix", "Sum");
-    }
-
     public bool Match(Symbol expected)
     {
         if (!IsMatch(expected))
@@ -297,31 +279,31 @@ private int GetBindingPower()
     /// </summary>
     protected void Postfix(Symbol token, string bindingPowerName = "Postfix")
     {
-        Register(token, new PostfixOperatorParselet(BindingPowers.Get(bindingPowerName)));
+        Register(token, new PostfixOperatorParselet(PrecedenceLevels.GetPrecedence(bindingPowerName)));
     }
 
     /// <summary>
     ///     Registers a prefix unary operator parselet for the given token and binding power.
     /// </summary>
     protected void Prefix(Symbol token, string bindingPowerName = "Prefix")
     {
-        Register(token, new PrefixOperatorParselet(BindingPowers.Get(bindingPowerName)));
+        Register(token, new PrefixOperatorParselet(PrecedenceLevels.GetPrecedence(bindingPowerName)));
     }
 
     /// <summary>
     ///     Registers a left-associative binary operator parselet for the given token and binding power.
     /// </summary>
     protected void InfixLeft(Symbol token, string bindingPowerName)
     {
-        Register(token, new BinaryOperatorParselet(BindingPowers.Get(bindingPowerName), false));
+        Register(token, new BinaryOperatorParselet(PrecedenceLevels.GetPrecedence(bindingPowerName), false));
     }
 
     /// <summary>
     ///     Registers a right-associative binary operator parselet for the given token and binding power.
     /// </summary>
     protected void InfixRight(Symbol token, string bindingPowerName)
     {
-        Register(token, new BinaryOperatorParselet(BindingPowers.Get(bindingPowerName), true));
+        Register(token, new BinaryOperatorParselet(PrecedenceLevels.GetPrecedence(bindingPowerName), true));
     }
 
     /// <summary>
@@ -332,6 +314,6 @@ protected void InfixRight(Symbol token, string bindingPowerName)
     /// <param name="bindingPower"></param>
     protected void Ternary(Symbol firstSymbol, Symbol secondSymbol, string bindingPowerName)
     {
-        Register(firstSymbol, new TernaryOperatorParselet(secondSymbol, BindingPowers.Get(bindingPowerName)));
+        Register(firstSymbol, new TernaryOperatorParselet(secondSymbol, PrecedenceLevels.GetPrecedence(bindingPowerName)));
     }
 }

Source/Silverfly/PrecedenceLevels.cs

@@ -0,0 +1,31 @@
+using System.Collections.Generic;
+
+namespace Silverfly;
+
+public abstract class PrecedenceLevels
+{
+    private readonly List<string> precedenceLevels = new List<string>();
+
+    public int GetPrecedence(string level)
+    {
+        var index = precedenceLevels.IndexOf(level);
+
+        return index == -1 ? precedenceLevels.Count : index;
+    }
+
+    public void AddPrecedence(string level)
+    {
+        if (!precedenceLevels.Contains(level))
+        {
+            precedenceLevels.Add(level);
+        }
+    }
+
+    public void InsertPrecedence(int index, string level)
+    {
+        if (!precedenceLevels.Contains(level))
+        {
+            precedenceLevels.Insert(index, level);
+        }
+    }
+}

Source/TestProject/TestParser.cs

@@ -10,7 +10,7 @@ protected override void InitParselets()
     {
         Register(PredefinedSymbols.Name, new NameParselet());
 
-        Register("(", new CallParselet(BindingPowers.Get("Call").Id));
+        Register("(", new CallParselet(PrecedenceLevels.GetPrecedence("Call")));
 
         Ternary("?", ":", "Conditional");
         InfixLeft(".", "Call");