Swiftgram/third-party/libprisma/Sources/Highlight.h

#pragma once
#include <string>
#include <vector>
#include <boost/regex.hpp>
#include <map>
#include <functional>

class GrammarPtr;
class GrammarToken;
class Pattern;
class TokenList;

class LanguageTree;

struct Grammar {
    std::vector<GrammarToken> tokens;
};

class GrammarPtr
{
public:
    GrammarPtr(std::shared_ptr<LanguageTree> tree, size_t path);

    const Grammar* operator->() const;
    const Grammar* get() const;

private:
    std::shared_ptr<LanguageTree> m_tree;
    size_t m_path;
};

class Pattern
{
public:
    Pattern(std::string_view pattern, boost::regex_constants::syntax_option_type flags, bool lookbehind, bool greedy, std::string alias, GrammarPtr inside)
        : Pattern(pattern, flags, lookbehind, greedy, alias, std::make_shared<GrammarPtr>(inside))
    {

    }

    Pattern(std::string_view pattern, boost::regex_constants::syntax_option_type flags, bool lookbehind = false, bool greedy = false, std::string alias = "", std::shared_ptr<GrammarPtr> inside = nullptr)
        : m_regex(boost::regex(std::string{pattern}, flags | boost::regex_constants::optimize))
        , m_lookbehind(lookbehind)
        , m_greedy(greedy)
        , m_alias(alias)
        , m_inside(inside)
    {
    }

    std::string_view match(bool& success, size_t& pos, std::string_view text) const
    {
        try {
            boost::cmatch m;
            
            auto flags = boost::regex_constants::match_not_dot_newline;
            auto match = boost::regex_search(text.data() + pos, text.data() + text.size(), m, m_regex, flags);
            if (match)
            {
                success = true;
                pos += m.position();
                
                if (m_lookbehind && m[1].matched)
                {
                    // change the match to remove the text matched by the Prism lookbehind group
                    auto lookbehindLength = m[1].length();
                    pos += lookbehindLength;
                    
                    return text.substr(pos, m[0].length() - lookbehindLength);
                }
                
                return text.substr(pos, m[0].length());
            }
        } catch(...) {
        }

        return {};
    }

    bool lookbehind() const
    {
        return m_lookbehind;
    }

    bool greedy() const
    {
        return m_greedy;
    }

    std::string alias() const
    {
        return m_alias;
    }

    const Grammar* inside() const;

private:
    boost::regex m_regex;
    bool m_lookbehind;
    bool m_greedy;
    std::string m_alias;
    std::shared_ptr<GrammarPtr> m_inside;
};

class PatternPtr
{
public:
    PatternPtr(std::shared_ptr<LanguageTree> tree, size_t path);

    const Pattern* operator->() const
    {
        return get();
    }

    const Pattern* get() const;

private:
    std::shared_ptr<LanguageTree> m_tree;
    size_t m_path;
};

class GrammarToken
{
public:
    GrammarToken(const std::string name, std::vector<PatternPtr> patterns)
        : m_name(name)
        , m_patterns(std::move(patterns))
    {

    }

    const std::string &name() const
    {
        return m_name;
    }

    std::vector<PatternPtr>::const_iterator cbegin() const noexcept
    {
        return m_patterns.cbegin();
    }

    std::vector<PatternPtr>::const_iterator cend() const noexcept
    {
        return m_patterns.cend();
    }

private:
    std::string m_name;
    const std::vector<PatternPtr> m_patterns;
};