ulib/3party/bnflite/bnflite.h

/*************************************************************************\
*   BNF Lite is a C++ template library for lightweight grammar parsers    *
*   Copyright (c) 2017 by Alexander A. Semjonov.  ALL RIGHTS RESERVED.    *
*                                                                         *
*   Permission is hereby granted, free of charge, to any person           *
*   obtaining  a copy of this software and associated documentation       *
*   files (the "Software"), to deal in the Software without restriction,  *
*   including without limitation the rights to use, copy, modify, merge,  *
*   publish, distribute, sublicense, and/or sell copies of the Software,  *
*   and to permit persons to whom the Software is furnished to do so,     *
*   subject to the following conditions:                                  *
*                                                                         *
*   The above copyright notice and this permission notice shall be        *
*   included in all copies or substantial portions of the Software.       *
*                                                                         *
*   THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,       *
*   EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF    *
*   MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.*
*   IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY  *
*   CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,  *
*   TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH         *
*   THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.            *
\*************************************************************************/

#ifndef BNFLITE_H
#define BNFLITE_H

#include <string.h>
#include <string>
#include <list>
#include <vector>
#include <bitset>
#include <map>
#include <algorithm>
#include <typeinfo>

namespace bnf {
// BNF (Backus-Naur form) is a notation for describing syntax of computer languages
// BNF Lite is the source code template library implementing the way to support BNF specifications
// BNF Terms:
// * Production rule is formal BNF expression which is a conjunction of a series
//   of more concrete rules:
//      production_rule ::= <rule_1>...<rule_n> | <rule_n_1>...<rule_m>;
// * e.g.
//      <digit> ::= <0> | <1> | <2> | <3> | <4> | <5> | <6> | <7> | <8> | <9>
//      <number> ::= <digit> | <digit> <number>
//      where the number is just a digit or another number with one more digit;
// Now this example can be presented in C++ friendly notation:
//      Lexem Digit = Token("0") | "1"  | "2" | "4" | "5" | "6" | "7" | "8" | "9";
//      RULE(Number) = Digit | Digit + Number;
// where:
//      * Token is a terminal production;
//      * Lexem (or LEXEM) is a lexical production;
//      * Rule (or RULE) is used here as synonym of syntax production
// To parse any number (e.g. 532) it is just enough to call the bnf::Analyze(Number, "532")

enum Limits {
    maxCharNum = 256,
    maxLexemLength = 1024,
    maxRepeate = 4096,
    maxEmptyStack = 16
};

enum Status {
    eNone = 0,
    eOk = 1,
    eRet = 0x8,
    e1st = 0x10,
    eSkip = 0x20,
    eTry = 0x40,
    eNull = 0x80,
    eRest = 0x0100,
    eNoData = 0x0200,
    eOver = 0x0400,
    eEof = 0x0800,
    eBadRule = 0x1000,
    eBadLexem = 0x2000,
    eSyntax = 0x4000,
    eError = ((~(unsigned int) 0) >> 1) + 1
};

class _Tie;
class _And;
class _Or;
class _Cycle;

/* context class to support the first kind of callback */
class _Base// base parser class
{
public:
    std::vector<const char *> cntxV;// public for internal extensions
protected:
    friend class Token;
    friend class Lexem;
    friend class Rule;
    friend class _And;
    friend class _Or;
    friend class _Cycle;
    int level;
    const char *pstop;

    int _chk_stack()
    {
        static const char *org;
        static int cnt;
        if (org != cntxV.back()) {
            org = cntxV.back();
            cnt = 0;
        } else if (++cnt > maxEmptyStack)
            return eOver | eError;
        return 0;
    }

    const char *(*zero_parse)(const char *);

    int catch_error(const char *ptr)// attempt to catch general syntax error
    {
        return eSyntax | eError;
    }

    virtual void _erase(int low, int up = 0)
    {
        cntxV.erase(cntxV.begin() + low, up ? cntxV.begin() + up : cntxV.end());
    }

    virtual std::pair<void *, int> _pre_call(void *callback)
    {
        return std::make_pair((void *) 0, 0);
    }

    virtual void _post_call(std::pair<void *, int> up){};
    virtual void _do_call(std::pair<void *, int> up,
                          void *callback,
                          size_t org,
                          const char *name){};
    virtual void _stub_call(size_t org, const char *name){};

public:
    int _analyze(_Tie &root, const char *text, size_t *);
    _Base(const char *(*pre)(const char *) )
        : level(1),
          pstop(0),
          zero_parse(pre ? pre : base_parser){};
    virtual ~_Base(){};

    // default pre-parser procedure to skip special symbols
    static const char *base_parser(const char *ptr)
    {
        for (char cc = *ptr; cc != 0; cc = *++ptr) {
            if (cc != ' ' && cc != '\t' && cc != '\n' && cc != '\r') { break; }
        }
        return ptr;
    }
};

#if !defined(_MSC_VER)
#define _NAME_OFF 0
#else
#define _NAME_OFF 6
#endif

/* internal base class to support multiform relationships between different BNFlite elements */
class _Tie {
    bool _is_compound();

protected:
    friend class _Base;
    friend class ExtParser;
    friend class _And;
    friend class _Or;
    friend class _Cycle;
    friend class Token;
    friend class Lexem;
    friend class Rule;

    bool inner;
    mutable std::vector<const _Tie *> use;
    mutable std::list<const _Tie *> usage;
    std::string name;

    template<class T>
    static void _setname(T *t, const char *name = 0)
    {
        static int cnt = 0;
        if (name) {
            t->name = name;
        } else {
            t->name = typeid(*t).name() + _NAME_OFF;
            for (int i = ++cnt; i != 0; i /= 10) {
                t->name += '0' + i - (i / 10) * 10;
            }
        }
    }

    void _clone(const _Tie *lnk)
    {
        usage.swap(lnk->usage);
        for (std::list<const _Tie *>::const_iterator usg = usage.begin();
             usg != usage.end(); ++usg) {
            for (size_t i = 0; i < (*usg)->use.size(); i++) {
                if ((*usg)->use[i] == lnk) { (*usg)->use[i] = this; }
            }
        }
        use.swap(lnk->use);
        for (size_t i = 0; i < use.size(); i++) {
            if (!use[i]) continue;
            std::list<const _Tie *>::iterator itr =
                std::find(use[i]->usage.begin(), use[i]->usage.end(), lnk);
            *itr = this;
        }
        if (lnk->inner) { delete lnk; }
    }

    _Tie(std::string nm = "") : inner(false), name(nm){};

    explicit _Tie(const _Tie *lnk) : inner(true), name(lnk->name)
    {
        _clone(lnk);
    }

    _Tie(const _Tie &link) : inner(link.inner), name(link.name)
    {
        _clone(&link);
    }

    virtual ~_Tie()
    {
        for (size_t i = 0; i < use.size(); i++) {
            const _Tie *lnk = use[i];
            if (lnk) {
                lnk->usage.remove(this);
                for (size_t j = 0; j < use.size(); j++) {
                    if (use[j] == lnk) { use[j] = 0; }
                }
                if (lnk->inner && lnk->usage.size() == 0) { delete lnk; }
            }
        }
    }

    static int call_1st(const _Tie *lnk, _Base *parser)
    {
        return lnk->_parse(parser);
    }

    void _clue(const _Tie &link)
    {
        if (!use.size() || _is_compound()) {
            use.push_back(&link);
        } else {
            if (use[0]) {
                use[0]->usage.remove(this);
                if (use[0]->inner && use[0]->usage.size() == 0) {
                    delete use[0];
                }
            }
            use[0] = &link;
        }
        link.usage.push_back(this);
    }

    template<class T>
    static T *_safe_delete(T *t)
    {
        if (t->usage.size() != 0) {
            if (!t->inner) { return new T(t); }
        }
        return 0;
    }

    virtual int _parse(_Base *parser) const throw() = 0;

public:
    void setName(const char *name) { this->name = name; }

    const char *getName() { return name.c_str(); }

    _And operator+(const _Tie &link);
    _And operator+(const char *s);
    _And operator+(bool (*f)(const char *, size_t));
    friend _And operator+(const char *s, const _Tie &lnk);
    friend _And operator+(bool (*f)(const char *, size_t), const _Tie &lnk);
    _Or operator|(const _Tie &link);
    _Or operator|(const char *s);
    _Or operator|(bool (*f)(const char *, size_t));
    friend _Or operator|(const char *s, const _Tie &lnk);
    friend _Or operator|(bool (*f)(const char *, size_t), const _Tie &lnk);

    // Support Augmented BNF constructions like "<a>*<b><element>" to implement repetition;
    // In ABNF <a> and <b> imply at least <a> and at most <b> occurrences of the element;
    // e.g *<element> allows any number(from 0 to infinity, 1*<element> requires at least one;
    // 3*3<element> allows exactly 3 and 1*2<element> allows one or two.
    _Cycle operator()(int at_least,
                      int total);// ABNF case <a>.<b>*<element> as element(a,b)
    _Cycle operator*();          // ABNF case *<element> (from 0 to infinity)
    _Cycle
    operator!();// ABNF case <0>.<1>*<element> or <1><element> (at least one)
};

/* implementation of parsing control rules */
template<const unsigned int flg, const char cc>
class _Ctrl : public _Tie {
protected:
    friend class _Tie;

    virtual int _parse(_Base *parser) const throw() { return flg; }

    explicit _Ctrl(const _Ctrl *ctrl) : _Tie(ctrl){};
    _Ctrl(const _Ctrl &control) : _Tie(control){};

public:
    explicit _Ctrl() : _Tie(std::string(1, cc)){};

    ~_Ctrl() { _safe_delete(this); }
};

/* Null operation, immediate successful return */
typedef _Ctrl<eOk, 'N'> Null;// stub for some constructions (e.g. "zero-or-one")

/* Force Return, immediate return from conjunction rule to impact disjunction rule */
typedef _Ctrl<eOk | eRet, 'R'> Return;

/* Switch to use "Accept First" strategy for disjunction rule instead "Accept Best" */
typedef _Ctrl<e1st, '1'> AcceptFirst;

/* Try to catch syntax error in current conjunction rule */
typedef _Ctrl<eOk | eTry, 'T'> Try;

/* Check but do not accept next statement for conjunction rule */
typedef _Ctrl<eOk | eSkip, 'S'> Skip;

/* Force syntax error */
typedef _Ctrl<eError | eSyntax, 'E'> Catch;

/* interface class for tokens */
class Token : public _Tie {
    Token &operator=(const _Tie &);
    explicit Token(const _Tie &);

public:
    class interval_set : protected std::map<wchar_t, bool> {
    public:
        interval_set()
        {
            insert(std::make_pair(0, false));
            insert(std::make_pair(WCHAR_MAX, false));
        }

        bool test(wchar_t key) const { return (--upper_bound(key))->second; }

        void reset(wchar_t key) { set(key, 0, false); }

        void set(wchar_t key, size_t rep = 0, bool val = true)
        {
            wchar_t key_end = key + rep + 1;
            if (key == 0 || key_end == WCHAR_MAX) return;
            std::map<wchar_t, bool>::iterator right_begin = lower_bound(key);
            std::map<wchar_t, bool>::iterator left_begin = right_begin;
            --left_begin;
            std::map<wchar_t, bool>::iterator right_end = upper_bound(key_end);
            std::map<wchar_t, bool>::iterator left_end = right_end;
            --left_end;
            if (left_end->second == val)
                if (left_end->first >= key_end && right_begin == left_end)
                    erase(right_begin);
                else
                    erase(right_begin, right_end);
            else {
                std::map<wchar_t, bool>::iterator itr =
                    insert(std::make_pair(key_end, left_end->second)).first;
                if (right_begin->first < itr->first) erase(right_begin, itr);
            }
            if (left_begin->second != val) insert(std::make_pair(key, val));
        }

        void flip()
        {
            for (std::map<wchar_t, bool>::iterator itr = begin(); itr != end();
                 ++itr)
                itr->second = !itr->second;
        }
    };

protected:
    friend class _Tie;
#if defined(BNFLITE_WIDE)
    interval_set match;
#else
    std::bitset<bnf::maxCharNum> match;
#endif
    explicit Token(const Token *tkn) : _Tie(tkn), match(tkn->match){};

    virtual int _parse(_Base *parser) const throw()
    {
        const char *cc = parser->cntxV.back();
        if (parser->level) cc = parser->zero_parse(cc);
        char c = *((unsigned char *) cc);
        if (match.test(c)) {
            if (parser->level) {
                parser->cntxV.push_back(cc);
                parser->_stub_call(parser->cntxV.size() - 1, name.c_str());
            }
            parser->cntxV.push_back(++cc);
            return c ? eOk : eOk | eEof;
        }
        return c ? eNone : eEof;
    }

public:
    Token(const char c) : _Tie(std::string(1, c))
    {
        Add(c, 0);
    };// create single char token

    Token(int fst, int lst) : _Tie(std::string(1, fst).append("-") += lst)
    {
        Add(fst, lst);
    };// create token by ASCII charactes in range

    Token(const char *s) : _Tie(std::string(s))
    {
        Add(s);
    };// create token by C string sample

    Token(const char *s, const Token &token)
        : _Tie(std::string(s)),
          match(token.match)
    {
        Add(s);
    };// create token by both C string sample and another token set

    Token(const Token &token) : _Tie(token), match(token.match){};

    virtual ~Token() { _safe_delete(this); }

    void
    Add(int fst,
        int lst = 0,
        const char *sample =
            "")// add characters in range fst...lst exept mentioned in sample;
    {
        switch (lst) {// lst == 0|1: add single | upper&lower case character(s)
        case 1:
            if (fst >= 'A' && fst <= 'Z')
                match.set(fst - 'A' + 'a');
            else if (fst >= 'a' && fst <= 'z')
                match.set(fst - 'a' + 'A');
        case 0:
            match.set((unsigned char) fst);
            break;
        default:
            for (int i = fst; i <= lst; i++) { match.set((unsigned char) i); }
            Remove(sample);
        }
    }

    void Add(const char *sample)
    {
        while (*sample) { match.set((unsigned char) *sample++); }
    }

    void Remove(int fst, int lst = 0)
    {
        for (int i = fst; i <= (lst ? lst : fst); i++) {
            match.reset((unsigned char) i);
        }
    }

    void Remove(const char *sample)
    {
        while (*sample) { match.reset((unsigned char) *sample++); }
    }

    int GetSymbol(int next = 1)// get first short symbol
    {
        for (unsigned int i = next; i < maxCharNum; i++) {
            if (match.test(i)) return i;
        }
        return 0;
    }

    Token &Invert()// invert token to build construction to not match
    {
        match.flip();
        return *this;
    }
};
#if __cplusplus > 199711L
inline Token
operator""_T(const char *sample, size_t len)
{
    return Token(std::string(sample, len).c_str());
}
#endif

/*  standalone callback wrapper class */
class Action : public _Tie {
    bool (*action)(const char *lexem, size_t len);
    Action(_Tie &);

protected:
    friend class _Tie;
    explicit Action(const Action *a) : _Tie(a), action(a->action){};

    int _parse(_Base *parser) const throw()
    {
        std::vector<const char *>::reverse_iterator itr =
            parser->cntxV.rbegin() + 1;
        return (*action)(*itr, parser->cntxV.back() - *itr);
    }

public:
    Action(bool (*action)(const char *lexem, size_t len), const char *name = "")
        : _Tie(name),
          action(action){};

    virtual ~Action() { _safe_delete(this); }
};

/* internal class to support conjunction constructions of BNFlite elements */
class _And : public _Tie {
protected:
    friend class _Tie;
    friend class Lexem;

    _And(const _Tie &b1, const _Tie &b2) : _Tie("")
    {
        (name = b1.name).append("+") += b2.name;
        _clue(b1);
        _clue(b2);
    }

    explicit _And(const _And *rl) : _Tie(rl){};

    virtual int _parse(_Base *parser) const throw()
    {
        int stat = 0;
        size_t save = 0;
        size_t size = parser->cntxV.size();
        for (unsigned i = 0; i < use.size(); i++, stat &= ~(eSkip | eOk)) {
            stat |= use[i]->_parse(parser);
            if (!(stat & eOk) || (stat & eError)
                || ((stat & eEof)
                    && (parser->cntxV.back() == parser->cntxV[size - 1]))) {
                if (parser->level && (stat & eTry) && !(stat & eError)
                    && !save) {
                    stat |= parser->catch_error(parser->cntxV.back());
                }
                parser->_erase(size);
                return stat & ~(eTry | eSkip | eOk);
            } else {
                if (save) {
                    parser->cntxV.resize(save);
                    save = 0;
                }
                if (stat & eSkip) { save = parser->cntxV.size(); }
            }
        }
        return eOk | (stat & ~(eTry | eSkip));
    }

public:
    ~_And() { _safe_delete(this); }

    _And &operator+(const _Tie &rule2)
    {
        name.append("+") += rule2.name;
        _clue(rule2);
        return *this;
    }

    _And &operator+(const char *s)
    {
        name.append("+") += s;
        _clue(Token(s));
        return *this;
    }

    _And &operator+(bool (*f)(const char *, size_t))
    {
        name += "+()";
        _clue(Action(f));
        return *this;
    }

    friend _And operator+(const char *s, const _Tie &link);
    friend _And operator+(bool (*f)(const char *, size_t), const _Tie &link);
};

inline _And
_Tie::operator+(const _Tie &rule2)
{
    return _And(*this, rule2);
}

inline _And
_Tie::operator+(const char *s)
{
    return _And(*this, Token(s));
}

inline _And
_Tie::operator+(bool (*f)(const char *, size_t))
{
    return _And(*this, Action(f));
}

inline _And
operator+(const char *s, const _Tie &link)
{
    return _And(Token(s), link);
}

inline _And
operator+(bool (*f)(const char *, size_t), const _Tie &link)
{
    return _And(Action(f), link);
}

/* internal class to support disjunction constructions of BNFlite elements */
class _Or : public _Tie {
protected:
    friend class _Tie;

    _Or(const _Tie &b1, const _Tie &b2) : _Tie("")
    {
        (name = b1.name).append("|") += b2.name;
        _clue(b1);
        _clue(b2);
    }

    explicit _Or(const _Or *rl) : _Tie(rl){};

    virtual int _parse(_Base *parser) const throw()
    {
        int stat = 0;
        int tstat = 0;
        int max = 0;
        int tmp = -1;
        size_t size = parser->cntxV.size();
        for (unsigned i = 0; i < use.size();
             i++, stat &= ~(eOk | eRet | eEof | eError)) {
            size_t msize = parser->cntxV.size();
            if (msize > size) {
                parser->cntxV.push_back(parser->cntxV[size - 1]);
            }
            stat |= use[i]->_parse(parser);
            if (stat & (eOk | eError)) {
                tmp = parser->cntxV.back() - parser->cntxV[size - 1];
                if ((tmp > max) || (tmp > 0 && (stat & (eRet | e1st)))
                    || (tmp >= 0 && (stat & eError))) {
                    max = tmp;
                    tstat = stat;
                    if (msize > size) { parser->_erase(size, msize + 1); }
                    if (stat & (eRet | e1st | eError)) { break; }
                    continue;
                }
            }
            if (parser->cntxV.size() > msize) { parser->_erase(msize); }
        }
        return (max || tmp >= 0 ? tstat | eOk : tstat & ~eOk) & ~(e1st | eRet);
    }

public:
    ~_Or() { _safe_delete(this); }

    _Or &operator|(const _Tie &rule2)
    {
        name.append("|") += rule2.name;
        _clue(rule2);
        return *this;
    }

    _Or &operator|(const char *s)
    {
        name.append("|") += s;
        _clue(Token(s));
        return *this;
    }

    _Or &operator|(bool (*f)(const char *, size_t))
    {
        name += "|()";
        _clue(Action(f));
        return *this;
    }

    friend _Or operator|(const char *s, const _Tie &link);
    friend _Or operator|(bool (*f)(const char *, size_t), const _Tie &link);
};

inline _Or
_Tie::operator|(const _Tie &rule2)
{
    return _Or(*this, rule2);
}

inline _Or
_Tie::operator|(const char *s)
{
    return _Or(*this, Token(s));
}

inline _Or
_Tie::operator|(bool (*f)(const char *, size_t))
{
    return _Or(*this, Action(f));
}

inline _Or
operator|(const char *s, const _Tie &link)
{
    return _Or(Token(s), link);
}

inline _Or
operator|(bool (*f)(const char *, size_t), const _Tie &link)
{
    return _Or(Action(f), link);
}

inline bool
_Tie::_is_compound()
{
    return dynamic_cast<_And *>(this) || dynamic_cast<_Or *>(this);
}

/* interface class for lexem */
class Lexem : public _Tie {
    Lexem &operator=(const class Rule &);
    Lexem(const Rule &rule);

protected:
    friend class _Tie;
    explicit Lexem(Lexem *lxm) : _Tie(lxm){};

    virtual int _parse(_Base *parser) const throw()
    {
        if (!use.size()) return eError | eBadLexem;
        if (!parser->level || dynamic_cast<const Action *>(use[0]))
            return use[0]->_parse(parser);
        size_t size = parser->cntxV.size();
        parser->cntxV.push_back(parser->zero_parse(parser->cntxV.back()));
        parser->level--;
        int stat = use[0]->_parse(parser);
        parser->level++;
        if ((stat & eOk) && parser->cntxV.size() - size > 1) {
            parser->_stub_call(size - 1, name.c_str());
            if (parser->cntxV.back() > parser->pstop)
                parser->pstop = parser->cntxV.back();
            parser->cntxV[(++size)++] = parser->cntxV.back();
        }
        parser->cntxV.resize(size);
        return stat;
    }

public:
    Lexem(const char *literal, bool cs = 0) : _Tie()
    {
        int size = strlen(literal);
        switch (size) {
        case 1:
            this->operator=(Token(literal[0], cs));
        case 0:
            break;
        default: {
            _And _and(Token(literal[0], cs), Token(literal[1], cs));
            for (int i = 2; i < size; i++) {
                _and.operator+((const _Tie &) Token(literal[i], cs));
            }
            this->operator=(_and);
        }
        }
        _setname(this, literal);
    }

    explicit Lexem() : _Tie() { _setname(this); }

    virtual ~Lexem() { _safe_delete(this); }

    Lexem(const _Tie &link) : _Tie()
    {
        _setname(this, 0);
        _clue(link);
    }

    Lexem &operator=(const Lexem &lexem)
    {
        if (&lexem != this) _clue(lexem);
        return *this;
    }

    Lexem &operator=(const _Tie &link)
    {
        _clue(link);
        return *this;
    }
};

/* interface class for BNF rules */
class Rule : public _Tie {
    void *callback;

protected:
    friend class _Tie;
    friend class _And;
    explicit Rule(const Rule *rl) : _Tie(rl), callback(rl->callback){};

    virtual int _parse(_Base *parser) const throw()
    {
        if (!use.size() || !parser->level) return eError | eBadRule;
        if (dynamic_cast<const Action *>(use[0])) {
            return use[0]->_parse(parser);
        }
        size_t size = parser->cntxV.size();
        std::pair<void *, int> up = parser->_pre_call(callback);
        int stat = use[0]->_parse(parser);
        if ((stat & eOk) && parser->cntxV.size() - size > 1) {
            parser->_do_call(up, callback, size, name.c_str());
            if (parser->cntxV.back() > parser->pstop)
                parser->pstop = parser->cntxV.back();
            parser->cntxV[(++size)++] = parser->cntxV.back();
        }
        parser->cntxV.resize(size);
        parser->_post_call(up);
        return stat;
    }

public:
    explicit Rule() : _Tie(), callback(0) { _setname(this); }

    virtual ~Rule() { _safe_delete(this); }

    Rule(const _Tie &link) : _Tie(), callback(0)
    {
        const Rule *rl = dynamic_cast<const Rule *>(&link);
        if (rl) {
            _clone(&link);
            callback = rl->callback;
            name = rl->name;
        } else {
            _clue(link);
            callback = 0;
            _setname(this);
        }
    }

    Rule &operator=(const _Tie &link)
    {
        _clue(link);
        return *this;
    }

    Rule &operator=(const Rule &rule)
    {
        if (&rule == this) return *this;
        return this->operator=((const _Tie &) rule);
    }
    template<class U>
    friend Rule &Bind(Rule &rule, U (*callback)(std::vector<U> &));
    template<class U>
    Rule &operator[](U (*callback)(std::vector<U> &));
};

/* friendly debug interface */
#define LEXEM(lexem)                                                           \
    Lexem lexem;                                                               \
    lexem.setName(#lexem);                                                     \
    lexem
#define RULE(rule)                                                             \
    Rule rule;                                                                 \
    rule.setName(#rule);                                                       \
    rule

/* internal class to support repeat constructions of BNF elements */
class _Cycle : public _Tie {
    unsigned int min, max;
    int flag;

protected:
    friend class _Tie;
    explicit _Cycle(const _Cycle *u)
        : _Tie(u),
          min(u->min),
          max(u->max),
          flag(u->flag){};
    _Cycle(const _Cycle &w) : _Tie(w), min(w.min), max(w.max), flag(w.flag){};

    int _parse(_Base *parser) const throw()
    {
        int stat;
        unsigned int i;
        for (stat = 0, i = 0; i < max;
             i++, stat &= ~(e1st | eTry | eSkip | eRet | eOk)) {
            stat |= use[0]->_parse(parser);
            if ((stat & (eOk | eError)) == eOk) continue;
            return i < min ? stat & ~eOk : stat | parser->_chk_stack() | eOk;
        }
        return stat | flag | eOk;
    }

    _Cycle(int at_least,
           const _Tie &link,
           int total = maxRepeate,
           int limit = maxRepeate)
        : _Tie(std::string("@")),
          min(at_least),
          max(total),
          flag(total < limit ? eNone : eOver | eError)
    {
        _clue(link);
    }

public:
    ~_Cycle() { _safe_delete(this); }

    friend _Cycle operator*(int at_least, const _Tie &link);
    friend _Cycle Repeat(int at_least, const Rule &rule, int total, int limit);
    friend _Cycle
    Iterate(int at_least, const Lexem &lexem, int total, int limit);
    friend _Cycle
    Series(int at_least, const Token &token, int total, int limit);
};

inline _Cycle
_Tie::operator*()
{
    return _Cycle(0, *this);
}

inline _Cycle
_Tie::operator!()
{
    return _Cycle(0, *this, 1);
}

inline _Cycle
_Tie::operator()(int at_least, int total)
{
    return _Cycle(at_least, *this, total);
}

inline _Cycle
operator*(int at_least, const _Tie &link)
{
    return _Cycle(at_least, link);
}

inline _Cycle
Repeat(int at_least,
       const Rule &rule,
       int total = maxLexemLength,
       int limit = maxRepeate)
{
    return _Cycle(at_least, rule, total, limit);
}

inline _Cycle
Iterate(int at_least,
        const Lexem &lexem,
        int total = maxLexemLength,
        int limit = maxLexemLength)
{
    return _Cycle(at_least, lexem, total, limit);
}

inline _Cycle
Series(int at_least,
       const Token &token,
       int total = maxLexemLength,
       int limit = maxCharNum)
{
    return _Cycle(at_least, token, total, limit);
}

/* context class to support the second kind of callback */
template<class U>
class _Parser : public _Base {
protected:
    std::vector<U> *cntxU;
    unsigned int off;

    void _erase(int low, int up = 0)
    {
        cntxV.erase(cntxV.begin() + low, up ? cntxV.begin() + up : cntxV.end());
        if (cntxU && level)
            cntxU->erase(cntxU->begin() + (low - off) / 2,
                         up ? cntxU->begin() + (up - off) / 2 : cntxU->end());
    }

    virtual std::pair<void *, int> _pre_call(void *callback)
    {
        std::pair<void *, int> up = std::make_pair(cntxU, off);
        cntxU = callback ? new std::vector<U> : 0;
        off = callback ? cntxV.size() : 0;
        return up;
    }

    virtual void _post_call(std::pair<void *, int> up)
    {
        if (cntxU) { delete cntxU; }
        cntxU = (std::vector<U> *) up.first;
        off = up.second;
    }

    virtual void _do_call(std::pair<void *, int> up,
                          void *callback,
                          size_t org,
                          const char *name)
    {
        if (callback) {
            if (up.first) {
                ((std::vector<U> *) up.first)
                    ->push_back(U(reinterpret_cast<U (*)(std::vector<U> &)>(
                                      callback)(*cntxU),
                                  cntxV[org], cntxV.back() - cntxV[org], name));
            } else {
                reinterpret_cast<U (*)(std::vector<U> &)>(callback)(*cntxU);
            }
        } else if (up.first) {
            ((std::vector<U> *) up.first)
                ->push_back(U(cntxV[org], cntxV.back() - cntxV[org], name));
        }
    }

    virtual void _stub_call(size_t org, const char *name)
    {
        if (cntxU) {
            cntxU->push_back(U(cntxV[org], cntxV.back() - cntxV[org], name));
        }
    }

public:
    _Parser(const char *(*f)(const char *), std::vector<U> *v)
        : _Base(f),
          cntxU(v),
          off(0){};
    virtual ~_Parser(){};

    int _get_result(U &u)
    {
        if (cntxU && cntxU->size()) {
            u.data = cntxU->front().data;
            return 0;
        } else
            return eNull;
    }
    template<class W>
    friend Rule &Bind(Rule &rule, W (*callback)(std::vector<W> &));
};

inline int
_Base::_analyze(_Tie &root, const char *text, size_t *plen)
{
    cntxV.push_back(text);
    cntxV.push_back(text);
    int stat = root._parse(this);
    const char *ptr = zero_parse(pstop > cntxV.back() ? pstop : cntxV.back());
    if (plen) *plen = ptr - text;
    return stat | (*ptr ? eError | eRest : 0);
}

/* User interface template to support the second kind of callback */
/* The user need to specify own 'Foo' abstract type to develop own callbaks */
/* like: Interface<Foo> CallBack(std::vector<Interface<Foo>>& res); */
template<typename Data = bool>
struct Interface {
    Data data;       //  user data element
    const char *text;//  pointer to parsed text according to bound Rule
    size_t length;   //  length of parsed text according to bound Rule
    const char *name;//  the name of bound Rule
    Interface(const Interface &ifc,
              const char *text,
              size_t length,
              const char *name)
        : data(ifc.data),
          text(text),
          length(length),
          name(
              name){};// mandatory constructor with user data to be called from library
    Interface(const char *text, size_t length, const char *name)
        : data(),
          text(text),
          length(length),
          name(
              name){};//  mandatory default constructor to be called from library
    Interface(Data data, std::vector<Interface> &res, const char *name = "")
        : data(data),
          text(res.size() ? res[0].text : ""),
          length(res.size() ? res[res.size() - 1].text - res[0].text
                         + res[res.size() - 1].length
                            : 0),
          name(
              name){};// constructor to pass data from user's callback to library
    Interface(const Interface &front,
              const Interface &back,
              const char *name = "")
        : data(),
          text(front.text),
          length(back.text - front.text + back.length),
          name(
              name){};// constructor to pass data from user's callback to library
    Interface() : data(), text(0), length(0), name(0){};// default constructor

    static Interface
    ByPass(std::vector<Interface> &res)// simplest user callback example
    {
        return res.size() ? res[0] : Interface();
    }// just to pass data to upper level

    int _get_pstop(const char **pstop)
    {
        if (pstop) *pstop = text + length;
        return length ? eNone : eNull;
    }
};

/* Private parsing interface */
template<class U>
inline int
_Analyze(_Tie &root, U &u, const char *(*pre_parse)(const char *) )
{
    if (typeid(U) == typeid(Interface<>)) {
        _Base base(pre_parse);
        return base._analyze(root, u.text, &u.length);
    } else {
        std::vector<U> v;
        _Parser<U> parser(pre_parse, &v);
        return parser._analyze(root, u.text, &u.length) | parser._get_result(u);
    }
}

/* Primary interface set to start parsing of text against constructed rules */
template<class U>
inline int
Analyze(_Tie &root,
        const char *text,
        const char **pstop,
        U &u,
        const char *(*pre_parse)(const char *) = 0)
{
    u.text = text;
    return _Analyze(root, u, pre_parse) | u._get_pstop(pstop);
}

template<class U>
inline int
Analyze(_Tie &root,
        const char *text,
        U &u,
        const char *(*pre_parse)(const char *) = 0)
{
    u.text = text;
    return _Analyze(root, u, pre_parse) | u._get_pstop(0);
}

inline int
Analyze(_Tie &root,
        const char *text,
        const char **pstop = 0,
        const char *(*pre_parse)(const char *) = 0)
{
    Interface<> u;
    u.text = text;
    return _Analyze(root, u, pre_parse) | u._get_pstop(pstop);
}

/* Create association between Rule and user's callback */
template<class U>
inline Rule &
Bind(Rule &rule, U (*callback)(std::vector<U> &))
{
    rule.callback = reinterpret_cast<void *>(callback);
    return rule;
}

template<class U>
inline Rule &
Rule::operator[](U (*callback)(std::vector<U> &))// for C++11
{
    this->callback = reinterpret_cast<void *>(callback);
    return *this;
}

};    // namespace bnf
#endif// BNFLITE_H