From 6c4f39708bfa0c1d8d9afab299ef538c6183204e Mon Sep 17 00:00:00 2001
From: Uko Kokņevičs
Date: Sun, 18 Aug 2024 23:56:26 +0800
Subject: Changed the grammar to allow bare top-level expressions only in REPL.

---
 .../src/main/java/lv/enes/orang/parser/Parser.java | 27 ++++++++++++++++------
 1 file changed, 20 insertions(+), 7 deletions(-)

(limited to 'parser/src/main/java/lv')

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 3a2e931..9103123 100644
--- a/parser/src/main/java/lv/enes/orang/parser/Parser.java
+++ b/parser/src/main/java/lv/enes/orang/parser/Parser.java
@@ -27,9 +27,9 @@ public class Parser {
 		return parser.parseProgram();
 	}
 
-	public static Program parseProgram(String in) throws ParserException {
+	public static Program parseReplProgram(String in) throws ParserException {
 		var parser = new Parser(in);
-		return parser.parseProgram();
+		return parser.parseReplProgram();
 	}
 
 	private final PeekableStream<Token> input;
@@ -59,6 +59,15 @@ public class Parser {
 		return new Program(Collections.unmodifiableList(statements));
 	}
 
+	public Program parseReplProgram() throws ParserException {
+		var statements = new ArrayList<Statement>();
+		while (!maybeConsumeToken(Token.Type.EOF)) {
+			statements.add(parseReplLine());
+			maybeConsumeToken(Token.Type.SEMICOLON);
+		}
+		return new Program(Collections.unmodifiableList(statements));
+	}
+
 	private static boolean isNotBinaryOp(Token token) {
 		return switch (token.type()) {
 			case ASTERISK, SLASH, PLUS, MINUS, QUESTION_EQUAL, SLASH_EQUAL, GREATER, GREATER_EQUAL, LESS, LESS_EQUAL
@@ -275,6 +284,14 @@ public class Parser {
 		return new LetInExpression(Collections.unmodifiableList(bindings), body);
 	}
 
+	private Statement parseReplLine() throws ParserException {
+		if (input.peek().type() == Token.Type.DEF) {
+			return parseStatement();
+		} else {
+			return new ExpressionStatement(parseExpression());
+		}
+	}
+
 	private Expression parseSimpleExpression() throws ParserException {
 		return switch (input.peek().type()) {
 			case PAREN_LEFT -> {
@@ -307,11 +324,7 @@ public class Parser {
 	}
 
 	private Statement parseStatement() throws ParserException {
-		if (input.peek().type() == Token.Type.DEF) {
-			return parseDefinition();
-		} else {
-			return new ExpressionStatement(parseExpression());
-		}
+		return parseDefinition();
 	}
 
 	private Expression parseString() throws ParserException {
-- 
cgit v1.2.3