match parsing

compiler/Parser.cs

@@ -234,15 +234,34 @@ public class Parser
             return new NodeStatementWhile(TokensFrom(startIndex), condition, thenBlock);
         }
 
-        var target = ParseExpression();
+        if (TryExpectKeyword(Keyword.Match))
-
-        if (TryExpectSymbol(Symbol.Equal))
         {
-            var value = ParseExpression();
+            var target = ParseExpression();
-            return new NodeStatementAssignment(TokensFrom(startIndex), target, value);
+            var cases = new List<NodeStatementMatch.Case>();
+
+            ExpectSymbol(Symbol.OpenCurly);
+            while (!TryExpectSymbol(Symbol.CloseCurly))
+            {
+                var caseStartIndex = index;
+                var name = ExpectIdent();
+                var body = ParseStatement();
+                cases.Add(new NodeStatementMatch.Case(TokensFrom(caseStartIndex), name, body));
+            }
+
+            return new NodeStatementMatch(TokensFrom(startIndex), target, cases);
         }
 
-        return new NodeStatementExpression(TokensFrom(startIndex), target);
+        {
+            var target = ParseExpression();
+
+            if (TryExpectSymbol(Symbol.Equal))
+            {
+                var value = ParseExpression();
+                return new NodeStatementAssignment(TokensFrom(startIndex), target, value);
+            }
+
+            return new NodeStatementExpression(TokensFrom(startIndex), target);
+        }
     }
 
     private NodeExpression ParseExpression(int minPrecedence = -1)
@@ -753,6 +772,18 @@ public class NodeStatementWhile(List<Token> tokens, NodeExpression condition, No
     public NodeStatement Block { get; } = block;
 }
 
+public class NodeStatementMatch(List<Token> tokens, NodeExpression target, List<NodeStatementMatch.Case> cases) : NodeStatement(tokens)
+{
+    public NodeExpression Target { get; } = target;
+    public List<Case> Cases { get; } = cases;
+
+    public class Case(List<Token> tokens, TokenIdent type, NodeStatement block) : Node(tokens)
+    {
+        public TokenIdent Type { get; } = type;
+        public NodeStatement Block { get; } = block;
+    }
+}
+
 public abstract class NodeExpression(List<Token> tokens) : Node(tokens);
 
 public class NodeExpressionIntLiteral(List<Token> tokens, TokenIntLiteral value) : NodeExpression(tokens)

compiler/Tokenizer.cs

@@ -389,6 +389,7 @@ public class Tokenizer
                         "struct" => new TokenKeyword(line, startColumn, column - startColumn, Keyword.Struct),
                         "packed" => new TokenKeyword(line, startColumn, column - startColumn, Keyword.Packed),
                         "enum" => new TokenKeyword(line, startColumn, column - startColumn, Keyword.Enum),
+                        "match" => new TokenKeyword(line, startColumn, column - startColumn, Keyword.Match),
                         "let" => new TokenKeyword(line, startColumn, column - startColumn, Keyword.Let),
                         "if" => new TokenKeyword(line, startColumn, column - startColumn, Keyword.If),
                         "else" => new TokenKeyword(line, startColumn, column - startColumn, Keyword.Else),
@@ -536,6 +537,7 @@ public enum Keyword
     Struct,
     Packed,
     Enum,
+    Match,
     Let,
     If,
     Else,
@@ -601,6 +603,7 @@ public static class TokenExtensions
             Keyword.Struct => "struct",
             Keyword.Packed => "packed",
             Keyword.Enum => "enum",
+            Keyword.Match => "enum",
             Keyword.Let => "let",
             Keyword.If => "if",
             Keyword.Else => "else",