for in syntax

compiler/NubLang/Syntax/Parser.cs

@@ -241,6 +241,8 @@ public sealed class Parser
                     return ParseIf(startIndex);
                 case Symbol.While:
                     return ParseWhile(startIndex);
+                case Symbol.For:
+                    return ParseFor(startIndex);
                 case Symbol.Let:
                     return ParseVariableDeclaration(startIndex);
                 case Symbol.Defer:
@@ -330,6 +332,23 @@ public sealed class Parser
         return new WhileSyntax(GetTokens(startIndex), condition, body);
     }
 
+    private ForSyntax ParseFor(int startIndex)
+    {
+        var itemName = ExpectIdentifier().Value;
+        string? indexName = null;
+
+        if (TryExpectSymbol(Symbol.Comma))
+        {
+            indexName = ExpectIdentifier().Value;
+        }
+
+        ExpectSymbol(Symbol.In);
+        var target = ParseExpression();
+        var body = ParseBlock();
+
+        return new ForSyntax(GetTokens(startIndex), itemName, indexName, target, body);
+    }
+
     private ExpressionSyntax ParseExpression(int precedence = 0)
     {
         var startIndex = _tokenIndex;

compiler/NubLang/Syntax/Syntax.cs

@@ -74,6 +74,8 @@ public record DeferSyntax(List<Token> Tokens, StatementSyntax Statement) : State
 
 public record WhileSyntax(List<Token> Tokens, ExpressionSyntax Condition, BlockSyntax Body) : StatementSyntax(Tokens);
 
+public record ForSyntax(List<Token> Tokens, string ElementName, string? IndexName, ExpressionSyntax Target, BlockSyntax Body) : StatementSyntax(Tokens);
+
 #endregion
 
 #region Expressions

compiler/NubLang/Syntax/Token.cs

@@ -8,6 +8,8 @@ public enum Symbol
     If,
     Else,
     While,
+    For,
+    In,
     Break,
     Continue,
     Return,

compiler/NubLang/Syntax/Tokenizer.cs

@@ -10,6 +10,8 @@ public sealed class Tokenizer
         ["if"] = Symbol.If,
         ["else"] = Symbol.Else,
         ["while"] = Symbol.While,
+        ["for"] = Symbol.For,
+        ["in"] = Symbol.In,
         ["break"] = Symbol.Break,
         ["continue"] = Symbol.Continue,
         ["return"] = Symbol.Return,