Introduce simple character literal

src/token/tokenizer.cpp

@@ -1,20 +1,21 @@
 #include <map>
+#include <optional>
 #include <stdexcept>
 #include <token/errors.hpp>
 #include <token/tokenizer.hpp>
 
 namespace Token
 {
-	std::tuple<int, bool> TryParseInt(std::string const & string)
+	std::optional<int> TryParseInt(std::string const & string)
 	{
 		try
 		{
 			int value = std::stoi(string);
-			return std::make_tuple(value, true);
+			return std::make_optional<int>(value);
 		}
 		catch(std::invalid_argument &)
 		{
-			return std::make_tuple(0, false);
+			return std::nullopt;
 		}
 	}
 
@@ -42,9 +43,19 @@ namespace Token
 			case '$':
 			{
 				auto const result = TryParseInt(string.substr(1, string.size()));
+
+				if (result.has_value())
+				{
+					return Token::CreateImmediateValueToken(
+						result.value(),
+						true,
+						lineNumber,
+						lineColumn);
+				}
+
 				return Token::CreateImmediateValueToken(
-					std::get<0>(result),
-					std::get<1>(result),
+					0,
+					false,
 					lineNumber,
 					lineColumn);
 			}
@@ -85,9 +96,19 @@ namespace Token
 			if (memoryPrefix == '$')
 			{
 				auto const result = TryParseInt(valueString);
+
+				if (result.has_value())
+				{
+					return Token::CreateMemoryToken(
+						result.value(),
+						true,
+						lineNumber,
+						lineColumn);
+				}
+
 				return Token::CreateMemoryToken(
-					std::get<0>(result),
-					std::get<1>(result),
+					0,
+					false,
 					lineNumber,
 					lineColumn);
 			}
@@ -224,6 +245,51 @@ end_state_loop:
 		}
 	}
 
+	// Modifies the lineColumn parameter to point at the character literal end
+	void Tokenizer::ParseCharacterLiteral(
+		std::string const & line,
+		int const lineNumber,
+		unsigned & lineColumn,
+		std::vector<Token> & tokens) const
+	{
+		for(unsigned int i = lineColumn + 1; i < line.size(); ++i)
+		{
+			if (line[i] == '\'')
+			{
+				// Character literal must be exactly length 3 for now (2x ' + 1
+				// character in between)
+				if (lineColumn + 2u != i)
+				{
+					tokens.emplace_back(Token::CreateImmediateValueToken(
+						0,
+						false,
+						lineNumber,
+						lineColumn));
+				}
+				else
+				{
+					tokens.emplace_back(Token::CreateImmediateValueToken(
+						line[i - 1],
+						true,
+						lineNumber,
+						lineColumn));
+				}
+
+				lineColumn = i;
+				return;
+			}
+		}
+
+		// Non terminated character literal!
+		tokens.emplace_back(Token::CreateImmediateValueToken(
+			0,
+			false,
+			lineNumber,
+			lineColumn));
+
+		lineColumn = line.size();
+	}
+
 	void Tokenizer::Tokenize(
 		std::string const & line,
 		int const lineNumber,
@@ -250,6 +316,12 @@ end_state_loop:
 						return;
 					}
 
+					if (line[column] == '\'')
+					{
+						ParseCharacterLiteral(line, lineNumber, column, tokens);
+						break;
+					}
+
 					columnTokenStart = column;
 
 					switch(line[column])