169 lines
5.4 KiB
C++
169 lines
5.4 KiB
C++
#include <utility>
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#include <cmath>
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#include "Lexer.hpp"
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Lexer::Lexer(string script) {
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Lexer::Script = std::move(script);
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Lexer::Position = 0;
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}
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vector<IToken*> Lexer::Lex() {
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vector<IToken*> tokens;
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while (true){
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IToken* next = Lexer::LexNext(Lexer::Next());
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tokens.push_back(next);
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if (next->GetKind() == TokenKind::EndOfFile)
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break;
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}
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return tokens;
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}
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char Lexer::Peek(){
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if (Lexer::Position > Lexer::Script.length())
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return '\0';
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return Lexer::Script[Lexer::Position];
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}
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char Lexer::Next(){
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char next = Peek();
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Lexer::Position++;
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return next;
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}
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IToken* Lexer::LexNext(char c){
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switch (c) {
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case '\0':
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return new SimpleToken(TokenKind::EndOfFile);
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case ' ': case '\t': case '\n': case '\r': case '\v': case '\f':
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return new SimpleToken(TokenKind::WhiteSpace);
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case '+':
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return new SimpleToken(TokenKind::PlusToken);
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case '-':
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return new SimpleToken(TokenKind::MinusToken);
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case '/':
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return new SimpleToken(TokenKind::SlashToken);
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case '*':
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return new SimpleToken(TokenKind::StarToken);
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case '=':
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if (Lexer::Peek() == '='){
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Lexer::Next();
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return new SimpleToken(TokenKind::EqualityToken);
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}
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return new SimpleToken(TokenKind::AssignmentToken);
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case '0': case '1': case '2': case '3': case '4': case '5': case '6': case '7': case '8': case '9':
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return LexNumber(c);
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case '_':
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return LexIdentifierOrKeyword(c);
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default:
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if (isalpha(c)){
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return LexIdentifierOrKeyword(c);
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}
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throw;
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}
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}
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int CharToInt(char c){
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switch (c){
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case '0': return 0;
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case '1': return 1;
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case '2': return 2;
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case '3': return 3;
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case '4': return 4;
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case '5': return 5;
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case '6': return 6;
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case '7': return 7;
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case '8': return 8;
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case '9': return 9;
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default: return -1;
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}
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}
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IToken* Lexer::LexNumber(char c){
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long int_value = CharToInt(c);
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double float_value = 0;
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short decimal_index = 0;
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bool has_point = false;
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bool is_searching = true;
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while (is_searching){
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char next = Lexer::Peek();
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int next_val = CharToInt(next);
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if (next_val == -1){
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switch (next){
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case '_':
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Lexer::Next();
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continue;
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case '.':
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Lexer::Next();
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has_point = true;
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decimal_index = 0;
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float_value = int_value;
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continue;
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default:
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is_searching = false;
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continue;
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}
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}
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else{
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Lexer::Next();
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if (has_point){
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decimal_index++;
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float_value += next_val / pow(10, decimal_index);
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}
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else {
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int_value *= 10;
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int_value += next_val;
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}
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}
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}
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if (has_point){
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return new FloatToken(float_value);
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}
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else{
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return new IntegerToken(int_value);
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}
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}
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unsigned constexpr const_hash(char const *input) {
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return *input ?
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static_cast<unsigned int>(*input) + 33 * const_hash(input + 1) :
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5381;
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}
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IToken* Lexer::LexIdentifierOrKeyword(char c){
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vector<char> charVec(1, c);
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while (true){
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char next = Lexer::Peek();
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if (next == '\0') break;
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if (isalpha(next) || next == '_'){
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Lexer::Next();
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charVec.push_back(next);
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}
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else{
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break;
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}
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}
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string s = string(charVec.begin(), charVec.end());
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switch (const_hash(s.c_str())){
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case const_hash("and"): return new SimpleToken(TokenKind::AndKeyword);
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case const_hash("break"): return new SimpleToken(TokenKind::BreakKeyword);
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case const_hash("do"): return new SimpleToken(TokenKind::DoKeyword);
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case const_hash("else"): return new SimpleToken(TokenKind::ElseKeyword);
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case const_hash("elseif"): return new SimpleToken(TokenKind::ElseIfKeyword);
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case const_hash("end"): return new SimpleToken(TokenKind::EndKeyword);
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case const_hash("false"): return new SimpleToken(TokenKind::FalseKeyword);
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case const_hash("for"): return new SimpleToken(TokenKind::ForKeyword);
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case const_hash("function"): return new SimpleToken(TokenKind::FunctionKeyword);
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case const_hash("if"): return new SimpleToken(TokenKind::IfKeyword);
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case const_hash("in"): return new SimpleToken(TokenKind::InKeyword);
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case const_hash("local"): return new SimpleToken(TokenKind::LocalKeyword);
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case const_hash("nil"): return new SimpleToken(TokenKind::NilKeyword);
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case const_hash("not"): return new SimpleToken(TokenKind::NotKeyword);
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case const_hash("or"): return new SimpleToken(TokenKind::OrKeyword);
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case const_hash("return"): return new SimpleToken(TokenKind::ReturnKeyword);
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case const_hash("then"): return new SimpleToken(TokenKind::ThenKeyword);
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case const_hash("true"): return new SimpleToken(TokenKind::TrueKeyword);
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case const_hash("while"): return new SimpleToken(TokenKind::WhileKeyword);
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default: return new IdentifierToken(s);
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}
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} |