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.

---
 .../src/main/java/lv/enes/orang/parser/Parser.java | 59 ++++++++++++++++------
 1 file changed, 44 insertions(+), 15 deletions(-)

(limited to 'parser/src')

diff --git a/parser/src/main/java/lv/enes/orang/parser/Parser.java b/parser/src/main/java/lv/enes/orang/parser/Parser.java
index 0ff1f78..06183a3 100644
--- a/parser/src/main/java/lv/enes/orang/parser/Parser.java
+++ b/parser/src/main/java/lv/enes/orang/parser/Parser.java
@@ -131,23 +131,51 @@ public class Parser {
 
 	private List<ArgSpec> parseArgSpecs() throws ParserException {
 		var argSpecs = new ArrayList<ArgSpec>();
-		while (true) {
-			if (input.peek().type() == Token.Type.IDENTIFIER) {
-				argSpecs.add(ArgSpec.named(input.next().literal()));
-			} else if (input.peek().type() == Token.Type.PAREN_LEFT) {
-				consumeToken(Token.Type.PAREN_LEFT);
-				consumeToken(Token.Type.PAREN_RIGHT);
-				argSpecs.add(ArgSpec.nothing());
-			} else if (input.peek().type() == Token.Type.UNDERSCORE) {
-				consumeToken(Token.Type.UNDERSCORE);
-				argSpecs.add(ArgSpec.ignored());
-			} else {
-				break;
-			}
+		while (couldStartArgSpec(input.peek().type())) {
+			argSpecs.add(parseArgSpec());
 		}
+		argSpecs.trimToSize();
 		return Collections.unmodifiableList(argSpecs);
 	}
 
+	private boolean couldStartArgSpec(Token.Type type) {
+		return switch (type) {
+			case IDENTIFIER, PAREN_LEFT, UNDERSCORE -> true;
+			default -> false;
+		};
+	}
+
+	private ArgSpec parseArgSpec() throws ParserException {
+		var token = input.next();
+		return switch (token.type()) {
+			case IDENTIFIER -> new ArgSpecNamed(token.literal());
+			case PAREN_LEFT -> {
+				if (maybeConsumeToken(Token.Type.PAREN_RIGHT)) {
+					yield new ArgSpecTuple(List.of());
+				}
+				var argspec = parseArgSpec();
+				if (maybeConsumeToken(Token.Type.COMMA)) {
+					yield parseArgSpecTuple(argspec);
+				}
+				consumeToken(Token.Type.PAREN_RIGHT);
+				yield argspec;
+			}
+			case UNDERSCORE -> ArgSpecIgnored.INSTANCE;
+			default -> throw new ParserException(STR."Unexpected token when parsing argspecs: \{token}");
+		};
+	}
+
+	private ArgSpec parseArgSpecTuple(ArgSpec first) throws ParserException {
+		var specs = new ArrayList<ArgSpec>();
+		specs.add(first);
+		do {
+			specs.add(parseArgSpec());
+			maybeConsumeToken(Token.Type.COMMA);
+		} while (!maybeConsumeToken(Token.Type.PAREN_RIGHT));
+		specs.trimToSize();
+		return new ArgSpecTuple(specs);
+	}
+
 	private Expression parseBinaryExpression() throws ParserException {
 		var lhs = parseCallExpression();
 		if (isNotBinaryOp(input.peek())) {
@@ -283,7 +311,7 @@ public class Parser {
 			case PAREN_LEFT -> {
 				consumeToken(Token.Type.PAREN_LEFT);
 				if (maybeConsumeToken(Token.Type.PAREN_RIGHT)) {
-					yield EmptyTupleLiteral.INSTANCE;
+					yield new TupleExpression(List.of());
 				}
 				var expr = parseExpression();
 				if (maybeConsumeToken(Token.Type.COMMA)) {
@@ -346,7 +374,8 @@ public class Parser {
 			exprs.add(parseExpression());
 			maybeConsumeToken(Token.Type.COMMA);
 		} while (!maybeConsumeToken(Token.Type.PAREN_RIGHT));
-		return new TupleExpression(new NonEmptyList<>(exprs));
+		exprs.trimToSize();
+		return new TupleExpression(exprs);
 	}
 
 	private Expression parseUnaryExpression() throws ParserException {
-- 
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