From 16a20ee8b08df919e93ea1b878013f9a2ad709fa Mon Sep 17 00:00:00 2001
From: Uko Kokņevičs
Date: Sat, 24 Aug 2024 03:54:25 +0800
Subject: Added fancier tuple argument specs. Made ArgSpec use visitor pattern
 to avoid problems the best way. Merged empty tuple and non-empty tuple
 classes.

---
 .../main/java/lv/enes/orang/checker/Checker.java   | 43 ++++++++++++++++------
 1 file changed, 32 insertions(+), 11 deletions(-)

(limited to 'checker/src/main/java')

diff --git a/checker/src/main/java/lv/enes/orang/checker/Checker.java b/checker/src/main/java/lv/enes/orang/checker/Checker.java
index 66b7dac..f926f59 100644
--- a/checker/src/main/java/lv/enes/orang/checker/Checker.java
+++ b/checker/src/main/java/lv/enes/orang/checker/Checker.java
@@ -64,12 +64,6 @@ public class Checker implements ExpressionVisitor<Void, CheckerException>, State
 		return null;
 	}
 
-	@Override
-	public Void visitEmptyTupleExpression() {
-		// Always ok
-		return null;
-	}
-
 	@Override
 	public Checker visitExpression(ExpressionStatement expr) throws CheckerException {
 		visit(expr.expr());
@@ -78,13 +72,40 @@ public class Checker implements ExpressionVisitor<Void, CheckerException>, State
 
 	@Override
 	public Void visitFnExpression(FnExpression expr) throws CheckerException {
-		var newScope = new HashSet<>(definitions);
-		for (var arg : expr.args()) {
-			if (arg instanceof ArgSpec.Named(String name)) {
-				newScope.add(name);
+		class Helper implements ArgSpecVisitor<HashSet<String>, CheckerException> {
+			private final HashSet<String> scope = new HashSet<>();
+
+			@Override
+			public HashSet<String> visitIgnored() {
+				// do nothing
+				return scope;
+			}
+
+			@Override
+			public HashSet<String> visitNamed(ArgSpecNamed named) throws CheckerException {
+				if (scope.contains(named.name())) {
+					throw new CheckerException(STR."Redefined argument \{named.name()}!");
+				}
+				scope.add(named.name());
+				return scope;
+			}
+
+			@Override
+			public HashSet<String> visitTuple(ArgSpecTuple tuple) throws CheckerException {
+				for (var child : tuple.children()) {
+					visit(child);
+				}
+				return scope;
 			}
 		}
-		new Checker(newScope).visit(expr.body());
+
+		var helper = new Helper();
+		for (var arg : expr.args()) {
+			helper.visit(arg);
+		}
+
+		helper.scope.addAll(definitions);
+		new Checker(helper.scope).visit(expr.body());
 		return null;
 	}
 
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