Started implementing lexer in lexer.cpp
The implementation for tokenise_symbol is already a lot nicer to look at and add to due to string/string_view operator overloading of ==. Furthermore, error handling through pair<> instead of making some custom structure which essentially does the same thing is already making me happy for this rewrite.
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asm/lexer.cpp
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215
asm/lexer.cpp
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/* Copyright (C) 2024 Aryadev Chavali
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* You may distribute and modify this code under the terms of the GPLv2
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* license. You should have received a copy of the GPLv2 license with
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* this file. If not, please write to: aryadev@aryadevchavali.com.
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* Created: 2024-04-14
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* Author: Aryadev Chavali
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* Description: Lexer for assembly language
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*/
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#include <lib/inst.h>
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#include <algorithm>
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#include <tuple>
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#include "./lexer.hpp"
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using std::string_view, std::pair, std::make_pair;
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constexpr auto VALID_SYMBOL =
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"abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789-_.:()%#$";
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bool is_char_in_s(char c, const char *s)
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{
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return string_view(s).find(c) != string::npos;
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}
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bool initial_match(string_view src, string_view match)
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{
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return (src.size() > match.size() && src.substr(0, match.size()) == match);
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}
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pair<token_t, lerr_t> tokenise_symbol(string_view &source, size_t &column)
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{
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auto end = source.find_first_not_of(VALID_SYMBOL);
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if (end == string::npos)
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end = source.size() - 1;
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string sym{source.substr(0, end)};
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source.remove_prefix(end);
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std::transform(sym.begin(), sym.end(), sym.begin(), ::toupper);
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token_t t{};
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if (initial_match(sym, "%CONST"))
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{
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t = token_t(token_type_t::PP_CONST, sym.substr(6));
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}
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else if (sym == "%USE")
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{
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t.type = token_type_t::PP_USE;
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}
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else if (sym == "%END")
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{
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t.type = token_type_t::PP_END;
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}
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else if (sym[0] == '%')
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{
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return make_pair(t, lerr_t::INVALID_PREPROCESSOR_DIRECTIVE);
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}
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else if (sym.size() > 1 && sym[0] == '$')
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{
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t = token_t(token_type_t::PP_REFERENCE, sym.substr(1));
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}
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else if (sym == "NOOP")
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{
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t.type = token_type_t::NOOP;
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}
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else if (sym == "HALT")
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{
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t.type = token_type_t::HALT;
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}
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else if (initial_match(sym, "PUSH.REG."))
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{
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t = token_t(token_type_t::PUSH_REG, sym.substr(9));
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}
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else if (initial_match(sym, "PUSH."))
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{
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t = token_t(token_type_t::PUSH, sym.substr(5));
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}
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else if (initial_match(sym, "POP."))
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{
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t = token_t(token_type_t::POP, sym.substr(4));
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}
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else if (initial_match(sym, "MOV."))
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{
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t = token_t(token_type_t::MOV, sym.substr(4));
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}
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else if (initial_match(sym, "DUP."))
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{
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t = token_t(token_type_t::DUP, sym.substr(4));
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}
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else if (initial_match(sym, "MALLOC.STACK."))
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{
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t = token_t(token_type_t::MALLOC_STACK, sym.substr(13));
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}
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else if (initial_match(sym, "MALLOC."))
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{
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t = token_t(token_type_t::MALLOC, sym.substr(7));
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}
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else if (initial_match(sym, "MSET.STACK."))
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{
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t = token_t(token_type_t::MSET_STACK, sym.substr(11));
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}
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else if (initial_match(sym, "MSET."))
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{
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t = token_t(token_type_t::MSET, sym.substr(5));
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}
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else if (initial_match(sym, "MGET.STACK."))
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{
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t = token_t(token_type_t::MGET_STACK, sym.substr(11));
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}
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else if (initial_match(sym, "MGET."))
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{
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t = token_t(token_type_t::MGET, sym.substr(5));
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}
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else if (sym == "MDELETE")
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{
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t.type = token_type_t::MDELETE;
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}
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else if (sym == "MSIZE")
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{
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t.type = token_type_t::MSIZE;
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}
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else if (initial_match(sym, "NOT."))
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{
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t = token_t(token_type_t::NOT, sym.substr(4));
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}
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else if (initial_match(sym, "OR."))
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{
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t = token_t(token_type_t::OR, sym.substr(3));
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}
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else if (initial_match(sym, "AND."))
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{
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t = token_t(token_type_t::AND, sym.substr(4));
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}
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else if (initial_match(sym, "XOR."))
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{
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t = token_t(token_type_t::XOR, sym.substr(4));
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}
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else if (initial_match(sym, "EQ."))
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{
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t = token_t(token_type_t::EQ, sym.substr(3));
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}
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else if (initial_match(sym, "LTE."))
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{
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t = token_t(token_type_t::LTE, sym.substr(4));
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}
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else if (initial_match(sym, "LT."))
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{
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t = token_t(token_type_t::LT, sym.substr(3));
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}
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else if (initial_match(sym, "GTE."))
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{
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t = token_t(token_type_t::GTE, sym.substr(4));
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}
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else if (initial_match(sym, "GT."))
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{
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t = token_t(token_type_t::GT, sym.substr(3));
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}
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else if (initial_match(sym, "SUB."))
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{
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t = token_t(token_type_t::SUB, sym.substr(4));
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}
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else if (initial_match(sym, "PLUS."))
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{
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t = token_t(token_type_t::PLUS, sym.substr(5));
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}
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else if (initial_match(sym, "MULT."))
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{
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t = token_t(token_type_t::MULT, sym.substr(5));
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}
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else if (initial_match(sym, "PRINT."))
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{
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t = token_t(token_type_t::PRINT, sym.substr(6));
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}
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else if (sym == "JUMP.ABS")
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{
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t.type = token_type_t::JUMP_ABS;
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}
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else if (sym == "JUMP.STACK")
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{
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t.type = token_type_t::JUMP_STACK;
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}
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else if (initial_match(sym, "JUMP.IF."))
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{
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t = token_t(token_type_t::JUMP_IF, sym.substr(8));
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}
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else if (sym == "CALL.STACK")
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{
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t.type = token_type_t::CALL_STACK;
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}
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else if (sym == "CALL")
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{
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t.type = token_type_t::CALL;
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}
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else if (sym == "RET")
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{
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t.type = token_type_t::RET;
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}
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else if (sym == "GLOBAL")
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{
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t.type = token_type_t::GLOBAL;
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}
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else
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{
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t.type = token_type_t::SYMBOL;
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}
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if (t.content == "")
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t.content = sym;
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t.column = column;
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column += sym.size();
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return make_pair(t, lerr_t::OK);
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}
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