Lexer+Reader: Don't tokenize comments

README.org

@@ -3,12 +3,10 @@
 #+LANGUAGE: en
 #+OPTIONS: toc:nil
 
-This is my implementation of the [[https://github.com/kanaka/mal][Make A Lisp]] project, done in C++20.
+This is an implementation of the [[https://github.com/kanaka/mal][Make A Lisp]] project, done in C++20.
 
 ** Usage
 
-Change the ~#if 0~ macro at the top of the ~stepX.cpp~ to ~#if 1~.
-
 *** Run the REPL
 
 #+BEGIN_SRC shell-script

src/functions.cpp

@@ -168,7 +168,6 @@ ADD_FUNCTION(
 		return makePtr<Constant>((result) ? Constant::True : Constant::False);
 	});
 
-// FIXME: (count {1}) infinite loop
 ADD_FUNCTION(
 	"count",
 	{

src/lexer.cpp

@@ -256,9 +256,6 @@ bool Lexer::consumeValue()
 
 bool Lexer::consumeComment()
 {
-	size_t column = m_column;
-	std::string comment;
-
 	ignore(); // ;
 
 	static std::unordered_set<char> exit = {
@@ -275,18 +272,9 @@ bool Lexer::consumeComment()
 			break;
 		}
 
-		comment += character;
 		ignore();
 	}
 
-	// Trim comment
-	comment.erase(comment.begin(),
-	              std::find_if(comment.begin(), comment.end(), [](char c) { return !std::isspace(c); }));
-	comment.erase(std::find_if(comment.rbegin(), comment.rend(), [](char c) { return !std::isspace(c); }).base(),
-	              comment.end());
-
-	m_tokens.push_back({ Token::Type::Comment, m_line, column, comment });
-
 	return true;
 }
 

src/lexer.h

@@ -34,7 +34,6 @@ struct Token {
 		String,       // "foobar"
 		Keyword,      // :keyword
 		Value,        // number, "nil", "true", "false", symbol
-		Comment,      // ;
 		Error,
 	};
 

src/reader.cpp

@@ -45,14 +45,7 @@ void Reader::read()
 
 	// Check for multiple expressions
 	if (!isEOF()) {
-		Token::Type type = peek().type;
+		Error::the().add("more than one sexp in input");
-		switch (type) {
-		case Token::Type::Comment:
-			break;
-		default:
-			Error::the().add("more than one sexp in input");
-			break;
-		};
 	}
 }
 
@@ -108,10 +101,6 @@ ValuePtr Reader::readImpl()
 	case Token::Type::Keyword: // :keyword
 		return readKeyword();
 		break;
-	case Token::Type::Comment: // ;
-		ignore();
-		return nullptr;
-		break;
 	case Token::Type::Value: // true, false, nil
 		return readValue();
 		break;
@@ -146,7 +135,11 @@ ValuePtr Reader::readList()
 
 	auto list = makePtr<List>();
 	while (!isEOF() && peek().type != Token::Type::ParenClose) {
-		list->add(readImpl());
+		auto node = readImpl();
+		if (node == nullptr) {
+			return nullptr;
+		}
+		list->add(node);
 	}
 
 	if (!consumeSpecific(Token { .type = Token::Type::ParenClose })) { // )
@@ -163,7 +156,11 @@ ValuePtr Reader::readVector()
 
 	auto vector = makePtr<Vector>();
 	while (!isEOF() && peek().type != Token::Type::BracketClose) {
-		vector->add(readImpl());
+		auto node = readImpl();
+		if (node == nullptr) {
+			return nullptr;
+		}
+		vector->add(node);
 	}
 
 	if (!consumeSpecific(Token { .type = Token::Type::BracketClose })) { // ]

src/stepA_mal.cpp

@@ -24,7 +24,6 @@
 #include "readline.h"
 #include "settings.h"
 
-#if 1
 namespace blaze {
 
 static blaze::Readline s_readline;
@@ -178,4 +177,3 @@ auto main(int argc, char* argv[]) -> int
 
 	return 0;
 }
-#endif