belka/elna
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Eugen Wissner
2022-06-05 15:16:04 +02:00
commit 9651c57760
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source/scanner.l Normal file
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%{
#define YY_NO_UNISTD_H
#define YY_USER_ACTION token_position = elna::source::position{ line_no, column_no }; column_no += yyleng;
#include <fstream>
#include "elna/source/lexer.hpp"
elna::source::token::value yylval{};
elna::source::position token_position{};
static std::size_t column_no = 1;
static std::size_t line_no = 1;
%}
%option noyywrap
%option never-interactive
%%
\-\-.* {
/* Skip the comment */
}
[\ \t\r] {
/* Skip the whitespaces */
}
\n {
++line_no;
column_no = 1;
}
if {
yylval.nil = nullptr;
return static_cast<int>(elna::source::token::type::when);
}
then {
yylval.nil = nullptr;
return static_cast<int>(elna::source::token::type::then);
}
while {
yylval.nil = nullptr;
return static_cast<int>(elna::source::token::type::loop);
}
do {
yylval.nil = nullptr;
return static_cast<int>(elna::source::token::type::_do);
}
proc {
yylval.nil = nullptr;
return static_cast<int>(elna::source::token::type::procedure);
}
begin {
yylval.nil = nullptr;
return static_cast<int>(elna::source::token::type::begin);
}
end {
yylval.nil = nullptr;
return static_cast<int>(elna::source::token::type::end);
}
const {
yylval.nil = nullptr;
return static_cast<int>(elna::source::token::type::let);
}
var {
yylval.nil = nullptr;
return static_cast<int>(elna::source::token::type::var);
}
True {
yylval.number = 1;
return static_cast<int>(elna::source::token::type::boolean);
}
False {
yylval.number = 0;
return static_cast<int>(elna::source::token::type::boolean);
}
[A-Za-z_][A-Za-z0-9_]* {
new((void *) &yylval.identifier) std::string(yytext);
return static_cast<int>(elna::source::token::type::identifier);
}
[0-9]+ {
yylval.number = strtol(yytext, NULL, 10);
return static_cast<int>(elna::source::token::type::number);
}
\( {
yylval.nil = nullptr;
return static_cast<int>(elna::source::token::type::left_paren);
}
\) {
yylval.nil = nullptr;
return static_cast<int>(elna::source::token::type::right_paren);
}
\>= {
new((void *) &yylval.identifier) std::string(1, 'g');
return static_cast<int>(elna::source::token::type::comparison_operator);
}
\<= {
new((void *) &yylval.identifier) std::string(1, 'l');
return static_cast<int>(elna::source::token::type::comparison_operator);
}
(>|<) {
new((void *) &yylval.identifier) std::string(yytext);
return static_cast<int>(elna::source::token::type::comparison_operator);
}
\/= {
new((void *) &yylval.identifier) std::string(1, 'n');
return static_cast<int>(elna::source::token::type::comparison_operator);
}
= {
yylval.nil = nullptr;
return static_cast<int>(elna::source::token::type::equals);
}
; {
yylval.nil = nullptr;
return static_cast<int>(elna::source::token::type::semicolon);
}
\. {
yylval.nil = nullptr;
return static_cast<int>(elna::source::token::type::dot);
}
, {
yylval.nil = nullptr;
return static_cast<int>(elna::source::token::type::comma);
}
(\+|\-) {
new((void *) &yylval.identifier) std::string(yytext);
return static_cast<int>(elna::source::token::type::term_operator);
}
(\*|\/) {
new((void *) &yylval.identifier) std::string(yytext);
return static_cast<int>(elna::source::token::type::factor_operator);
}
:= {
yylval.nil = nullptr;
return static_cast<int>(elna::source::token::type::assignment);
}
: {
yylval.nil = nullptr;
return static_cast<int>(elna::source::token::type::colon);
}
\^ {
yylval.nil = nullptr;
return static_cast<int>(elna::source::token::type::hat);
}
@ {
yylval.nil = nullptr;
return static_cast<int>(elna::source::token::type::at);
}
. {
return -1;
}
%%
namespace elna::source
{
result<lexer> tokenize(const std::filesystem::path& path)
{
int yytoken;
std::vector<token> tokens;
yyin = fopen(path.c_str(), "rb");
if (yyin == nullptr)
{
throw std::ios_base::failure("File does not exist");
}
do
{
yytoken = yylex();
if (yytoken < 0)
{
return result<lexer>(unexpected_character{ std::string{ yytext[0] }, path, token_position });
}
tokens.emplace_back(static_cast<token::type>(yytoken), std::move(yylval), token_position);
}
while (yytoken != 0);
return result<lexer>(std::in_place, std::move(tokens), position{ line_no, column_no }, path);
}
}