mirror of https://github.com/djcb/mu.git
129 lines
2.7 KiB
C++
129 lines
2.7 KiB
C++
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/*
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** Copyright (C) 2017 Dirk-Jan C. Binnema <djcb@djcbsoftware.nl>
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**
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** This library is free software; you can redistribute it and/or
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** modify it under the terms of the GNU Lesser General Public License
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** as published by the Free Software Foundation; either version 2.1
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** of the License, or (at your option) any later version.
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**
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** This library is distributed in the hope that it will be useful,
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** but WITHOUT ANY WARRANTY; without even the implied warranty of
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** MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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** Lesser General Public License for more details.
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**
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** You should have received a copy of the GNU Lesser General Public
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** License along with this library; if not, write to the Free
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** Software Foundation, 51 Franklin Street, Fifth Floor, Boston, MA
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** 02110-1301, USA.
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*/
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#include "tokenizer.hh"
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#include <cctype>
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#include <iostream>
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#include <algorithm>
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using namespace Mux;
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static bool
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is_separator (char c)
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{
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const auto seps = std::string (":()\"");
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if (isblank(c))
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return true;
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else
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return seps.find(c) != std::string::npos;
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}
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static Mux::Token
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op_or_value (size_t pos, const std::string& val)
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{
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auto s = val;
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std::transform(s.begin(), s.end(), s.begin(), ::tolower);
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if (s == "and")
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return Token{pos, Token::Type::And, val};
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else if (s == "or")
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return Token{pos, Token::Type::Or, val};
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else if (s == "xor")
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return Token{pos, Token::Type::Xor, val};
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else if (s == "not")
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return Token{pos, Token::Type::Not, val};
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else
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return Token{pos, Token::Type::Data, val};
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}
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static void
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unread_char (std::string& food, char kar, size_t& pos)
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{
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food = kar + food;
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--pos;
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}
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static Mux::Token
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eat_token (std::string& food, size_t& pos)
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{
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bool quoted{};
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bool escaped{};
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std::string value {};
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while (!food.empty()) {
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const auto kar = food[0];
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food.erase(0, 1);
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++pos;
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if (kar == '\\') {
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escaped = !escaped;
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if (escaped)
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continue;
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}
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if (kar == '"' && !escaped && quoted)
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return Token{pos, Token::Type::Data, value};
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if (!quoted && !escaped && is_separator(kar)) {
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if (!value.empty() && kar != ':') {
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unread_char (food, kar, pos);
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return op_or_value(pos, value);
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}
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if (kar == '"')
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quoted = true;
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if (quoted || isblank(kar))
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continue;
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switch (kar) {
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case '(': return {pos, Token::Type::Open, "("};
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case ')': return {pos, Token::Type::Close,")"};
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default: break;
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}
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}
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value += kar;
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escaped = false;
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}
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return {pos, Token::Type::Data, value};
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}
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Mux::Tokens
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Mux::tokenize (const std::string& s)
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{
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Tokens tokens{};
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std::string food{s};
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size_t pos{0};
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if (s.empty())
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return {};
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while (!food.empty())
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tokens.emplace_back(eat_token (food, pos));
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return tokens;
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}
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