From 9fa63143784c0e1a074a13a8743eee0f5d478c07 Mon Sep 17 00:00:00 2001
From: Riyyi <riyyi3@gmail.com>
Date: Sat, 25 Mar 2023 10:51:50 +0100
Subject: [PATCH] Reader: Improve error reporting

---
 src/lexer.h    |  2 +-
 src/reader.cpp | 54 ++++++++++++++++----------------------------------
 src/reader.h   |  2 +-
 3 files changed, 19 insertions(+), 39 deletions(-)

diff --git a/src/lexer.h b/src/lexer.h
index 175ab7d..c8fbcb2 100644
--- a/src/lexer.h
+++ b/src/lexer.h
@@ -33,7 +33,7 @@ struct Token {
 		At,           // @
 		String,       // "foobar"
 		Keyword,      // :keyword
-		Value,        // numbers, "true", "false", and "nil", symbols
+		Value,        // number, "true", "false", "nil", symbol
 		Comment,      // ;
 		Error,
 	};
diff --git a/src/reader.cpp b/src/reader.cpp
index 15b7868..d74fe19 100644
--- a/src/reader.cpp
+++ b/src/reader.cpp
@@ -38,32 +38,18 @@ void Reader::read()
 
 	m_node = readImpl();
 
-	// TODO: Move these to the appropriate functions
-	// Error checking
-
-	if (m_invalid_syntax) {
-		Error::the().addError("invalid read syntax: '" + std::string(1, m_error_character) + "'");
-		return;
-	}
-
-	if (m_is_unbalanced) {
-		Error::the().addError("expected '" + std::string(1, m_error_character) + "', got EOF");
+	if (Error::the().hasOtherError()) {
 		return;
 	}
 
+	// Check for multiple expressions
 	if (!isEOF()) {
 		Token::Type type = peek().type;
 		switch (type) {
-		case Token::Type::ParenOpen:  // (
-		case Token::Type::ParenClose: // )
-		case Token::Type::String:
-		case Token::Type::Value:
-			Error::the().addError("more than one sexp in input");
-			break;
 		case Token::Type::Comment:
 			break;
 		default:
-			Error::the().addError("unknown error");
+			Error::the().addError("more than one sexp in input");
 			break;
 		};
 	}
@@ -79,28 +65,25 @@ ASTNode* Reader::readImpl()
 	case Token::Type::Special: // ~@
 		return readSpliceUnquote();
 		break;
+	case Token::Type::ParenOpen: // (
+		return readList();
+		break;
+	case Token::Type::ParenClose: // )
+		Error::the().addError("invalid read syntax: ')'");
+		return nullptr;
+		break;
 	case Token::Type::BracketOpen: // [
 		return readVector();
 		break;
 	case Token::Type::BracketClose: // ]
-		m_invalid_syntax = true;
-		m_error_character = ']';
+		Error::the().addError("invalid read syntax: ']'");
 		return nullptr;
 		break;
 	case Token::Type::BraceOpen: // {
 		return readHashMap();
 		break;
 	case Token::Type::BraceClose: // }
-		m_invalid_syntax = true;
-		m_error_character = '}';
-		return nullptr;
-		break;
-	case Token::Type::ParenOpen: // (
-		return readList();
-		break;
-	case Token::Type::ParenClose: // )
-		m_invalid_syntax = true;
-		m_error_character = ')';
+		Error::the().addError("invalid read syntax: '}'");
 		return nullptr;
 		break;
 	case Token::Type::Quote: // '
@@ -166,8 +149,8 @@ ASTNode* Reader::readList()
 	}
 
 	if (!consumeSpecific(Token { .type = Token::Type::ParenClose })) { // )
-		m_error_character = ')';
-		m_is_unbalanced = true;
+		Error::the().addError("expected ')', got EOF");
+		return nullptr;
 	}
 
 	return list;
@@ -183,8 +166,7 @@ ASTNode* Reader::readVector()
 	}
 
 	if (!consumeSpecific(Token { .type = Token::Type::BracketClose })) { // ]
-		m_error_character = ']';
-		m_is_unbalanced = true;
+		Error::the().addError("expected ']', got EOF");
 	}
 
 	return vector;
@@ -218,8 +200,7 @@ ASTNode* Reader::readHashMap()
 	}
 
 	if (!consumeSpecific(Token { .type = Token::Type::BraceClose })) { // }
-		m_error_character = '}';
-		m_is_unbalanced = true;
+		Error::the().addError("expected '}', got EOF");
 	}
 
 	return hash_map;
@@ -316,8 +297,7 @@ ASTNode* Reader::readString()
 
 	// Unbalanced string
 	if (symbol.size() < 2 || symbol.front() != '"' || symbol.back() != '"') {
-		m_error_character = '"';
-		m_is_unbalanced = true;
+		Error::the().addError("expected '\"', got EOF");
 	}
 
 	return new String(symbol);
diff --git a/src/reader.h b/src/reader.h
index 1f30ec8..91dfb44 100644
--- a/src/reader.h
+++ b/src/reader.h
@@ -46,7 +46,7 @@ private:
 	ASTNode* readDeref();         // @
 	ASTNode* readString();        // "foobar"
 	ASTNode* readKeyword();       // :keyword
-	ASTNode* readValue();         // true, false, nil
+	ASTNode* readValue();         // number, "true", "false", "nil", symbol
 
 	void dumpImpl(ASTNode* node);