From 1fd741f7d5019b929affd29741b5ce92d7993f0f Mon Sep 17 00:00:00 2001
From: Uko Kokņevičs
Date: Thu, 22 Aug 2024 22:04:14 +0800
Subject: Fix bug in checker that made it not execute and made ArgSpec less
 likely to cause accidental errors.

---
 ast/src/main/java/lv/enes/orang/ast/ArgSpec.java   | 43 ++++++++++++----------
 .../main/java/lv/enes/orang/checker/Checker.java   |  8 +++-
 .../java/lv/enes/orang/value/PartialFunction.java  |  4 +-
 3 files changed, 32 insertions(+), 23 deletions(-)

diff --git a/ast/src/main/java/lv/enes/orang/ast/ArgSpec.java b/ast/src/main/java/lv/enes/orang/ast/ArgSpec.java
index 7fea2f4..8fa52be 100644
--- a/ast/src/main/java/lv/enes/orang/ast/ArgSpec.java
+++ b/ast/src/main/java/lv/enes/orang/ast/ArgSpec.java
@@ -1,34 +1,39 @@
 package lv.enes.orang.ast;
 
-public class ArgSpec {
-	public final Type type;
+public sealed interface ArgSpec {
+	enum Type {
+		IGNORED,
+		NOTHING,
+		NAMED,
+	}
 
-	// non-null if NAMED
-	public final String name;
+	Type getType();
 
-	private static final ArgSpec NOTHING = new ArgSpec(Type.NOTHING, null);
-	private static final ArgSpec IGNORED = new ArgSpec(Type.IGNORED, null);
+	static Ignored ignored() {
+		return Ignored.INSTANCE;
+	}
 
-	public static ArgSpec ignored() {
-		return IGNORED;
+	static Named named(String name) {
+		return new Named(name);
 	}
 
-	public static ArgSpec nothing() {
-		return NOTHING;
+	static Nothing nothing() {
+		return Nothing.INSTANCE;
 	}
 
-	public static ArgSpec named(String name) {
-		return new ArgSpec(Type.NAMED, name);
+	final class Ignored implements ArgSpec {
+		public static final Ignored INSTANCE = new Ignored();
+		private Ignored() {}
+		@Override public Type getType() { return Type.IGNORED; }
 	}
 
-	private ArgSpec(Type type, String name) {
-		this.type = type;
-		this.name = name;
+	record Named(String name) implements ArgSpec {
+		@Override public Type getType() { return Type.NAMED; }
 	}
 
-	public enum Type {
-		IGNORED,
-		NOTHING,
-		NAMED,
+	final class Nothing implements ArgSpec {
+		public static final Nothing INSTANCE = new Nothing();
+		private Nothing() {}
+		@Override public Type getType() { return Type.NOTHING; }
 	}
 }
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 446d3f1..14604b8 100644
--- a/checker/src/main/java/lv/enes/orang/checker/Checker.java
+++ b/checker/src/main/java/lv/enes/orang/checker/Checker.java
@@ -58,7 +58,9 @@ public class Checker implements ExpressionVisitor<Void, CheckerException>, State
 		if (definitions.hasDefinition(def.name())) {
 			throw new CheckerException(STR."Top-level definition '\{def.name()}' redefined!");
 		}
-		return new Checker(ImmutableScope.of(definitions, def.name(), true));
+		var ch = new Checker(ImmutableScope.of(definitions, def.name(), true));
+		ch.visit(def.body());
+		return ch;
 	}
 
 	@Override
@@ -79,7 +81,9 @@ public class Checker implements ExpressionVisitor<Void, CheckerException>, State
 	public Void visitFnExpression(FnExpression expr) throws CheckerException {
 		var args = new HashMap<String, Boolean>();
 		for (var arg : expr.args()) {
-			args.put(arg.name, true);
+			if (arg instanceof ArgSpec.Named(String name)) {
+				args.put(name, true);
+			}
 		}
 		new Checker(ImmutableScope.of(definitions, args)).visit(expr.body());
 		return null;
diff --git a/orang/src/main/java/lv/enes/orang/value/PartialFunction.java b/orang/src/main/java/lv/enes/orang/value/PartialFunction.java
index e73ba0c..d03bb13 100644
--- a/orang/src/main/java/lv/enes/orang/value/PartialFunction.java
+++ b/orang/src/main/java/lv/enes/orang/value/PartialFunction.java
@@ -12,8 +12,8 @@ public record PartialFunction(Scope<Value> scope, NonEmptyList<ArgSpec> remainin
 	public static Value of(Scope<Value> scope, NonEmptyList<ArgSpec> remainingArgs, Expression body, Value param) throws OrangRuntimeException {
 		var spec = remainingArgs.getFirst();
 		var newScope = MutableScope.of(scope);
-		switch (spec.type) {
-			case NAMED -> newScope.setDefinition(spec.name, param);
+		switch (spec.getType()) {
+			case NAMED -> newScope.setDefinition(((ArgSpec.Named)spec).name(), param);
 			case NOTHING -> {
 				if (!(param instanceof Nothing)) {
 					throw new OrangRuntimeException(STR."Expected () as a parameter but got \{param.typeName()}");
-- 
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