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/*
* Copyright (c) 2020, Benoit Lormeau <blormeau@outlook.com>
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
*
* 1. Redistributions of source code must retain the above copyright notice, this
* list of conditions and the following disclaimer.
*
* 2. Redistributions in binary form must reproduce the above copyright notice,
* this list of conditions and the following disclaimer in the documentation
* and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
* DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
* SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
* CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#pragma once
#include <AK/StringView.h>
namespace AK {
class GenericLexer {
public:
explicit GenericLexer(const StringView& input);
virtual ~GenericLexer();
size_t tell() const { return m_index; }
size_t tell_remaining() const { return m_input.length() - m_index; }
StringView remaining() const { return m_input.substring_view(m_index); }
bool is_eof() const;
char peek(size_t offset = 0) const;
bool next_is(char) const;
bool next_is(StringView) const;
bool next_is(const char*) const;
void retreat();
char consume();
bool consume_specific(char);
bool consume_specific(StringView);
bool consume_specific(const char*);
char consume_escaped_character(char escape_char = '\\', const StringView& escape_map = "n\nr\rt\tb\bf\f");
StringView consume(size_t count);
StringView consume_all();
StringView consume_line();
StringView consume_until(char);
StringView consume_until(const char*);
StringView consume_quoted_string(char escape_char = 0);
String consume_and_unescape_string(char escape_char = '\\');
void ignore(size_t count = 1);
void ignore_until(char);
void ignore_until(const char*);
/*
* Conditions are used to match arbitrary characters. You can use lambdas,
* ctype functions, or is_any_of() and its derivatives (see below).
* A few examples:
* - `if (lexer.next_is(isdigit))`
* - `auto name = lexer.consume_while([](char c) { return isalnum(c) || c == '_'; });`
* - `lexer.ignore_until(is_any_of("<^>"));`
*/
// Test the next character against a Condition
template<typename C>
bool next_is(C condition) const
{
return condition(peek());
}
// Consume and return characters while `condition` returns true
template<typename C>
StringView consume_while(C condition)
{
size_t start = m_index;
while (!is_eof() && condition(peek()))
m_index++;
size_t length = m_index - start;
if (length == 0)
return {};
return m_input.substring_view(start, length);
}
// Consume and return characters until `condition` return true
template<typename C>
StringView consume_until(C condition)
{
size_t start = m_index;
while (!is_eof() && !condition(peek()))
m_index++;
size_t length = m_index - start;
if (length == 0)
return {};
return m_input.substring_view(start, length);
}
// Ignore characters while `condition` returns true
template<typename C>
void ignore_while(C condition)
{
while (!is_eof() && condition(peek()))
m_index++;
}
// Ignore characters until `condition` return true
// We don't skip the stop character as it may not be a unique value
template<typename C>
void ignore_until(C condition)
{
while (!is_eof() && !condition(peek()))
m_index++;
}
protected:
StringView m_input;
size_t m_index { 0 };
};
constexpr auto is_any_of(const StringView& values)
{
return [values](auto c) { return values.contains(c); };
}
constexpr auto is_path_separator = is_any_of("/\\");
constexpr auto is_quote = is_any_of("'\"");
}
using AK::GenericLexer;
using AK::is_any_of;
using AK::is_path_separator;
using AK::is_quote;
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