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Diffstat (limited to 'lib/parse_plural.h')
| -rw-r--r-- | lib/parse_plural.h | 412 |
1 files changed, 412 insertions, 0 deletions
diff --git a/lib/parse_plural.h b/lib/parse_plural.h new file mode 100644 index 00000000..847bec35 --- /dev/null +++ b/lib/parse_plural.h @@ -0,0 +1,412 @@ +// ************************************************************************** +// * This file is part of the FreeFileSync project. It is distributed under * +// * GNU General Public License: http://www.gnu.org/licenses/gpl.html * +// * Copyright (C) 2008-2011 ZenJu (zhnmju123 AT gmx.de) * +// ************************************************************************** + +#ifndef PARSE_PLURAL_H_INCLUDED +#define PARSE_PLURAL_H_INCLUDED + +#include <list> +#include <memory> +#include <zen/string_base.h> + + +//http://www.gnu.org/software/hello/manual/gettext/Plural-forms.html +//http://translate.sourceforge.net/wiki/l10n/pluralforms +/* +Grammar for Plural forms parser +------------------------------- +expression: + conditional-expression + +conditional-expression: + logical-or-expression + logical-or-expression ? expression : expression + +logical-or-expression: + logical-and-expression + logical-or-expression || logical-and-expression + +logical-and-expression: + equality-expression + logical-and-expression && equality-expression + +equality-expression: + relational-expression + relational-expression == relational-expression + relational-expression != relational-expression + +relational-expression: + multiplicative-expression + multiplicative-expression > multiplicative-expression + multiplicative-expression < multiplicative-expression + multiplicative-expression >= multiplicative-expression + multiplicative-expression <= multiplicative-expression + +multiplicative-expression: + pm-expression + multiplicative-expression % pm-expression + +pm-expression: + N + Number + ( Expression ) +*/ + + + +//expression interface +struct Expression { virtual ~Expression() {} }; + +template <class T> +struct Expr : public Expression +{ + typedef T ValueType; + virtual ValueType eval() const = 0; +}; + +//specific binary expression based on STL function objects +template <class StlOp> +struct BinaryExp : public Expr<typename StlOp::result_type> +{ + typedef const Expr<typename StlOp::first_argument_type> SourceExp; + + BinaryExp(const SourceExp& lhs, const SourceExp& rhs, StlOp biop) : lhs_(lhs), rhs_(rhs), biop_(biop) {} + virtual typename StlOp::result_type eval() const { return biop_(lhs_.eval(), rhs_.eval()); } + const SourceExp& lhs_; + const SourceExp& rhs_; + StlOp biop_; +}; + +template <class StlOp> +inline +BinaryExp<StlOp> makeBiExp(const Expression& lhs, const Expression& rhs, StlOp biop) //throw (std::bad_cast) +{ + return BinaryExp<StlOp>(dynamic_cast<const Expr<typename StlOp::first_argument_type >&>(lhs), + dynamic_cast<const Expr<typename StlOp::second_argument_type>&>(rhs), biop); +} + +template <class Out> +struct TernaryExp : public Out +{ + TernaryExp(const Expr<bool>& ifExp, const Out& thenExp, const Out& elseExp) : ifExp_(ifExp), thenExp_(thenExp), elseExp_(elseExp) {} + virtual typename Out::ValueType eval() const { return ifExp_.eval() ? thenExp_.eval() : elseExp_.eval(); } + const Expr<bool>& ifExp_; + const Out& thenExp_; + const Out& elseExp_; +}; + +struct LiteralNumberEx : public Expr<int> +{ + LiteralNumberEx(int n) : n_(n) {} + virtual int eval() const { return n_; } + int n_; +}; + +struct NumberN : public Expr<int> +{ + NumberN(int& n) : n_(n) {} + virtual int eval() const { return n_; } + int& n_; +}; + + +typedef Zbase<char> Wstring; + + +class PluralForm +{ +public: + struct ParsingError {}; + + //.po format,e.g.: (n%10==1 && n%100!=11 ? 0 : n%10>=2 && n%10<=4 && (n%100<10 || n%100>=20) ? 1 : 2) + PluralForm(const Wstring& phrase) : n_(0) + { + Parser(phrase, //in + expr, n_, dump); //out + } + + int getForm(int n) const { n_ = n ; return expr->eval(); } + +private: + typedef std::list<std::shared_ptr<Expression> > DumpList; + + struct Token + { + enum Type + { + TK_TERNARY_QUEST, + TK_TERNARY_COLON, + TK_OR, + TK_AND, + TK_EQUAL, + TK_NOT_EQUAL, + TK_LESS, + TK_LESS_EQUAL, + TK_GREATER, + TK_GREATER_EQUAL, + TK_MODULUS, + TK_N, + TK_NUMBER, + TK_BRACKET_LEFT, + TK_BRACKET_RIGHT, + TK_END + }; + + Token(Type t) : type(t), number(0) {} + + Type type; + int number; //if type == TK_NUMBER + }; + + class Scanner + { + public: + Scanner(const Wstring& phrase) : stream(phrase), pos(stream.begin()) + { + tokens.push_back(std::make_pair("?" , Token::TK_TERNARY_QUEST)); + tokens.push_back(std::make_pair(":" , Token::TK_TERNARY_COLON)); + tokens.push_back(std::make_pair("||", Token::TK_OR )); + tokens.push_back(std::make_pair("&&", Token::TK_AND )); + tokens.push_back(std::make_pair("==", Token::TK_EQUAL )); + tokens.push_back(std::make_pair("!=", Token::TK_NOT_EQUAL )); + tokens.push_back(std::make_pair("<=", Token::TK_LESS_EQUAL )); + tokens.push_back(std::make_pair("<" , Token::TK_LESS )); + tokens.push_back(std::make_pair(">=", Token::TK_GREATER_EQUAL)); + tokens.push_back(std::make_pair(">" , Token::TK_GREATER )); + tokens.push_back(std::make_pair("%" , Token::TK_MODULUS )); + tokens.push_back(std::make_pair("n" , Token::TK_N )); + tokens.push_back(std::make_pair("N" , Token::TK_N )); + tokens.push_back(std::make_pair("(" , Token::TK_BRACKET_LEFT )); + tokens.push_back(std::make_pair(")" , Token::TK_BRACKET_RIGHT)); + } + + Token nextToken() + { + //skip whitespace + pos = std::find_if(pos, stream.end(), std::not1(std::ptr_fun(std::iswspace))); + + if (pos == stream.end()) return Token(Token::TK_END); + + for (TokenList::const_iterator i = tokens.begin(); i != tokens.end(); ++i) + if (startsWith(i->first)) + { + pos += i->first.size(); + return Token(i->second); + } + + Wstring::const_iterator digitEnd = std::find_if(pos, stream.end(), std::not1(std::ptr_fun(std::iswdigit))); + int digitCount = digitEnd - pos; + if (digitCount != 0) + { + Token out(Token::TK_NUMBER); + out.number = zen::toNumber<int>(Wstring(&*pos, digitCount)); + pos += digitCount; + return out; + } + + throw ParsingError(); //unknown token + } + + private: + bool startsWith(const Wstring& prefix) const + { + if (stream.end() - pos < static_cast<int>(prefix.size())) + return false; + return std::equal(prefix.begin(), prefix.end(), pos); + } + + typedef std::vector<std::pair<Wstring, Token::Type> > TokenList; + TokenList tokens; + + const Wstring stream; + Wstring::const_iterator pos; + }; + + + class Parser + { + public: + Parser(const Wstring& phrase, //in + const Expr<int>*& expr, int& n, PluralForm::DumpList& dump) ://out + scn(phrase), + tk(scn.nextToken()), + n_(n), + dump_(dump) + { + try + { + const Expression& e = parse(); + expr = &dynamic_cast<const Expr<int>&>(e); + } + catch (std::bad_cast&) { throw ParsingError(); } + + consumeToken(Token::TK_END); + } + + private: + void nextToken() { tk = scn.nextToken(); } + const Token& token() const { return tk; } + + void consumeToken(Token::Type t) + { + if (token().type != t) + throw ParsingError(); + nextToken(); + } + + const Expression& parse() { return parseConditional(); }; + + const Expression& parseConditional() + { + const Expression& e = parseLogicalOr(); + + if (token().type == Token::TK_TERNARY_QUEST) + { + nextToken(); + const Expression& thenEx = parse(); //associativity: <- + consumeToken(Token::TK_TERNARY_COLON); + const Expression& elseEx = parse(); // + + return manageObj(TernaryExp<Expr<int> >(dynamic_cast<const Expr<bool>&>(e), + dynamic_cast<const Expr<int>&>(thenEx), + dynamic_cast<const Expr<int>&>(elseEx))); + } + return e; + } + + const Expression& parseLogicalOr() + { + const Expression* e = &parseLogicalAnd(); + for (;;) //associativity: -> + if (token().type == Token::TK_OR) + { + nextToken(); + const Expression& rhs = parseLogicalAnd(); + e = &manageObj(makeBiExp(*e, rhs, std::logical_or<bool>())); + } + else break; + return *e; + } + + const Expression& parseLogicalAnd() + { + const Expression* e = &parseEquality(); + for (;;) //associativity: -> + if (token().type == Token::TK_AND) + { + nextToken(); + const Expression& rhs = parseEquality(); + + e = &manageObj(makeBiExp(*e, rhs, std::logical_and<bool>())); + } + else break; + return *e; + } + + const Expression& parseEquality() + { + const Expression& e = parseRelational(); + + Token::Type t = token().type; + if (t == Token::TK_EQUAL || t == Token::TK_NOT_EQUAL) //associativity: n/a + { + nextToken(); + const Expression& rhs = parseRelational(); + + if (t == Token::TK_EQUAL) return manageObj(makeBiExp(e, rhs, std::equal_to <int>())); + if (t == Token::TK_NOT_EQUAL) return manageObj(makeBiExp(e, rhs, std::not_equal_to<int>())); + } + return e; + } + + const Expression& parseRelational() + { + const Expression& e = parseMultiplicative(); + + Token::Type t = token().type; + if (t == Token::TK_LESS || //associativity: n/a + t == Token::TK_LESS_EQUAL || + t == Token::TK_GREATER || + t == Token::TK_GREATER_EQUAL) + { + nextToken(); + const Expression& rhs = parseMultiplicative(); + + if (t == Token::TK_LESS) return manageObj(makeBiExp(e, rhs, std::less <int>())); + if (t == Token::TK_LESS_EQUAL) return manageObj(makeBiExp(e, rhs, std::less_equal <int>())); + if (t == Token::TK_GREATER) return manageObj(makeBiExp(e, rhs, std::greater <int>())); + if (t == Token::TK_GREATER_EQUAL) return manageObj(makeBiExp(e, rhs, std::greater_equal<int>())); + } + return e; + } + + const Expression& parseMultiplicative() + { + const Expression* e = &parsePrimary(); + + for (;;) //associativity: -> + if (token().type == Token::TK_MODULUS) + { + nextToken(); + const Expression& rhs = parsePrimary(); + + //"compile-time" check: n % 0 + const LiteralNumberEx* literal = dynamic_cast<const LiteralNumberEx*>(&rhs); + if (literal && literal->eval() == 0) + throw ParsingError(); + + e = &manageObj(makeBiExp(*e, rhs, std::modulus<int>())); + } + else break; + return *e; + } + + const Expression& parsePrimary() + { + if (token().type == Token::TK_N) + { + nextToken(); + return manageObj(NumberN(n_)); + } + else if (token().type == Token::TK_NUMBER) + { + const int number = token().number; + nextToken(); + return manageObj(LiteralNumberEx(number)); + } + else if (token().type == Token::TK_BRACKET_LEFT) + { + nextToken(); + const Expression& e = parse(); + + consumeToken(Token::TK_BRACKET_RIGHT); + return e; + } + else + throw ParsingError(); + } + + template <class T> + const T& manageObj(const T& obj) + { + std::shared_ptr<Expression> newEntry(new T(obj)); + dump_.push_back(newEntry); + return static_cast<T&>(*dump_.back()); + } + + Scanner scn; + Token tk; + + int& n_; + DumpList& dump_; //manage polymorphc object lifetimes + }; + + const Expr<int>* expr; + mutable int n_; + + PluralForm::DumpList dump; //manage polymorphc object lifetimes +}; + +#endif // PARSE_PLURAL_H_INCLUDED |