Parse function calls

ASTPrinter.cs

@@ -130,4 +130,24 @@ class ASTPrinter : IVisitor<string>
 	{
 		return parenthesize("index", expr.Left, expr.Index);
 	}
+
+	public string visitCallExpr(Call expr)
+	{
+		var w = new StringWriter();
+		w.Write("(call ");
+		w.Write(print(expr.Left));
+		foreach (var arg in expr.Arguments)
+		{
+			if (arg == null)
+			{
+				w.Write(" _");
+			}
+			else
+			{
+				w.Write($" {print(arg)}");
+			}
+		}
+		w.Write(')');
+		return w.ToString();
+	}
 }

Expr.g.cs

@@ -23,6 +23,7 @@ public interface IVisitor<T> {
 	T visitRecordExpr(Record expr);
 	T visitSelectorExpr(Selector expr);
 	T visitIndexerExpr(Indexer expr);
+	T visitCallExpr(Call expr);
 }
 public class Sequence : Expr
 {
@@ -130,3 +131,12 @@ public class Indexer : Expr
 		return visitor.visitIndexerExpr(this);
 	}
 }
+public class Call : Expr
+{
+	public required Expr Left { get; init; }
+	public required Expr?[] Arguments { get; init; }
+	public override T accept<T>(IVisitor<T> visitor)
+	{
+		return visitor.visitCallExpr(this);
+	}
+}

Parser.cs

@@ -227,7 +227,24 @@ class Parser
 
 		if (match(TokenType.LParen))
 		{
-			throw new NotImplementedException("TODO apply");
+			var args = new List<Expr?>();
+			while (!check(TokenType.RParen))
+			{
+				if (match(TokenType.Blank))
+				{
+					args.Add(null);
+				}
+				else
+				{
+					args.Add(expression());
+				}
+				if (!match(TokenType.Comma))
+				{
+					break;
+				}
+			}
+			consume(TokenType.RParen, "Expect '(' after arguments.");
+			return new Call { Left = expr, Arguments = args.ToArray() };
 		}
 
 		return expr;

ast_classes.fsx

@@ -36,7 +36,9 @@ let types =
       { Name = "Selector"
         Fields = [ { Type = "Expr"; Name = "Left" }; { Type = "Name"; Name = "FieldName" } ] }
       { Name = "Indexer"
-        Fields = [ { Type = "Expr"; Name = "Left" }; { Type = "Expr"; Name = "Index" } ] } ]
+        Fields = [ { Type = "Expr"; Name = "Left" }; { Type = "Expr"; Name = "Index" } ] }
+      { Name = "Call"
+        Fields = [ { Type = "Expr"; Name = "Left" }; { Type = "Expr?[]"; Name = "Arguments" } ] } ]
 
 let visitorMethod baseName t = $"visit{t.Name}{baseName}"