Added number literals to Lexer

Also fixed bugs. I really should refactor the mess that is this Lexer.
This commit is contained in:
Pasha Bibko
2025-04-17 13:46:10 +01:00
parent 2f34a23ba2
commit e1fce699da
4 changed files with 97 additions and 47 deletions

View File

@@ -30,6 +30,7 @@ namespace LX
TOKEN_CASE(Token::SUB);
TOKEN_CASE(Token::MUL);
TOKEN_CASE(Token::DIV);
TOKEN_CASE(Token::NUMBER_LITERAL);
default:
return "Unknown: " + std::to_string(type);
@@ -58,7 +59,7 @@ namespace LX
{
if (auto keyword = keywords.find(word); keyword != keywords.end())
{
tokens.push_back({ keyword->second, word });
tokens.push_back({ keyword->second, "" });
}
else
@@ -67,6 +68,24 @@ namespace LX
}
}
struct LexerInfo
{
std::streamsize index = 0;
std::streamsize startOfWord = 0;
std::streamsize startOfNumberLiteral = 0;
std::streamsize startOfStringLiteral = 0;
bool isAlpha : 1 = false;
bool isNumeric : 1 = false;
bool inComment : 1 = false;
bool inStringLiteral : 1 = false;
bool isNextCharAlpha : 1 = false;
bool isNextCharNumeric : 1 = false;
bool wasLastCharAlpha : 1 = false;
bool wasLastCharNumeric : 1 = false;
};
const std::vector<Token> LX::LexicalAnalyze(std::ifstream& src, std::ofstream* log)
{
// Logs the start of the lexical analysis
@@ -87,69 +106,110 @@ namespace LX
src.read(&contents[0], len); // Transfers file to string
// Trackers for when the program is iterating over the file //
std::streamsize index = 0;
std::streamsize startOfWord = 0;
std::streamsize startOfStringLiteral = 0;
bool isAlpha = false;
bool inComment = false;
bool inStringLiteral = false;
bool wasLastCharAlpha = false;
LexerInfo info;
// Iterates over the file and turns it into tokens //
while (index < len)
while (info.index < len)
{
// Stores the current character for easy access
const char current = contents[index];
const char current = contents[info.index];
// Works out if the current character is alphabetic
isAlpha = (current >= 'a' && current <= 'z') || (current >= 'A' && current <= 'Z');
//
if (info.index + 1 < len)
{
const char next = contents[info.index + 1];
info.isNextCharAlpha = (next >= 'a' && next <= 'z') || (next >= 'A' && next <= 'Z');
info.isNextCharNumeric = (next >= '0' && next <= '9');
}
else
{
info.isNextCharAlpha = false;
info.isNextCharNumeric = false;
}
// Works out if the current character is alphabetic or numeric
info.isAlpha = (current >= 'a' && current <= 'z') || (current >= 'A' && current <= 'Z');
info.isNumeric = (current >= '0' && current <= '9');
// Updates string literal tracker and skips over rest if in a string literal
if (current == '"')
{
// Start of string literal
if (inStringLiteral == false)
if (info.inStringLiteral == false)
{
// Updates the neccesarry trackers
startOfStringLiteral = index + 1;
inStringLiteral = true;
info.startOfStringLiteral = info.index + 1;
info.inStringLiteral = true;
}
// End of string literal
else
{
// Adds the string literal token to the token vector
std::string lit(contents.data() + startOfStringLiteral, index - startOfStringLiteral);
std::string lit(contents.data() + info.startOfStringLiteral, info.index - info.startOfStringLiteral);
tokens.push_back({ Token::STRING_LITERAL, lit });
// Updates trackers
inStringLiteral = false;
info.inStringLiteral = false;
}
}
// Skips over rest if within a string literal
else if (inStringLiteral);
else if (info.inStringLiteral);
// Updates comment state
else if (current == '#')
{
inComment = !inComment;
info.inComment = !info.inComment;
}
// Skips over if within a comment
else if (inComment);
else if (info.inComment);
// Start of a word
else if (isAlpha == true && wasLastCharAlpha == false)
else if (info.isAlpha == true && info.wasLastCharAlpha == false)
{
startOfWord = index;
info.startOfWord = info.index;
// Single letter word
if (info.isNextCharAlpha == false)
{
TokenizeWord({ contents.data() + info.startOfWord, 1 }, tokens);
}
}
// End of a word
else if (info.isAlpha == true && info.isNextCharAlpha == false)
{
TokenizeWord({ contents.data() + info.startOfWord, (unsigned __int64)((info.index + 1) - info.startOfWord) }, tokens);
}
// During a word
else if (isAlpha == true);
else if (info.isAlpha == true);
// Start of a number
else if (info.isNumeric == true && info.wasLastCharNumeric == false)
{
info.startOfNumberLiteral = info.index;
if (info.isNextCharNumeric == false)
{
std::string num(contents.data() + info.startOfNumberLiteral, (unsigned __int64)(info.index + 1) - info.startOfNumberLiteral);
tokens.push_back({ Token::NUMBER_LITERAL, num });
}
}
// End of a number
else if (info.isNumeric == true && info.isNextCharNumeric == false)
{
std::string num(contents.data() + info.startOfNumberLiteral, (unsigned __int64)(info.index + 1) - info.startOfNumberLiteral);
tokens.push_back({ Token::NUMBER_LITERAL, num });
}
// During a number
else if (info.isNumeric == true);
// Operators (+, -, /, *)
else if (auto op = operators.find(current); op != operators.end())
@@ -163,26 +223,14 @@ namespace LX
else
{
// Throws an error to alert the user
throw InvalidCharInSource(index, current);
}
// End of a word
if (isAlpha == false && wasLastCharAlpha == true)
{
TokenizeWord({ contents.data() + startOfWord, (unsigned __int64)(index - startOfWord) }, tokens);
throw InvalidCharInSource(info.index, current);
}
// Updates trackers //
index++;
wasLastCharAlpha = isAlpha;
}
// Words are only added the iteration after they end so it has to be done like this //
if (wasLastCharAlpha && isAlpha)
{
std::string word(contents.data() + startOfWord, index - startOfWord);
TokenizeWord(word, tokens);
info.index++;
info.wasLastCharAlpha = info.isAlpha;
info.wasLastCharNumeric = info.isNumeric;
}
// Logs the tokens if logging is on //

View File

@@ -3,9 +3,9 @@
Started lexing file
-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
Token::IDENTIFIER: int
Token::FUNCTION
Token::IDENTIFIER: main
Token::IDENTIFIER: return
Token::IDENTIFIER: a
Token::NUMBER_LITERAL: 34
Token::ADD
Token::IDENTIFIER: b
Token::NUMBER_LITERAL: 4

View File

@@ -1,2 +1,3 @@
int main
return a## + b
func main
return 34 + 4

View File

@@ -39,6 +39,7 @@ namespace LX
// General tokens //
STRING_LITERAL,
NUMBER_LITERAL,
IDENTIFIER,
RETURN,