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llcalcparser.h 5.67 KiB
/*
* LLCalcParser.h
* Copyright 2008 Aimee Walton.
* $LicenseInfo:firstyear=2008&license=viewerlgpl$
* Second Life Viewer Source Code
* Copyright (C) 2008, Linden Research, Inc.
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation;
* version 2.1 of the License only.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*
* Linden Research, Inc., 945 Battery Street, San Francisco, CA 94111 USA
* $/LicenseInfo$
*
*/
#ifndef LL_CALCPARSER_H
#define LL_CALCPARSER_H
#include <boost/spirit/version.hpp>
#if !defined(SPIRIT_VERSION) || SPIRIT_VERSION < 0x2010
#error "At least Spirit version 2.1 required"
#endif
// Add this in if we want boost math constants.
#include <boost/bind.hpp>
//#include <boost/math/constants/constants.hpp>
#include <boost/spirit/include/phoenix.hpp>
#include <boost/spirit/include/qi.hpp>
namespace expression {
//TODO: If we can find a better way to do this with boost::pheonix::bind lets do it
//namespace { // anonymous
template <typename T>
T min_glue(T a, T b)
{
return std::min(a, b);
}
template <typename T>
T max_glue(T a, T b)
{
return std::max(a, b);
}
struct lazy_pow_
{
template <typename X, typename Y>
struct result { typedef X type; };
template <typename X, typename Y>
X operator()(X x, Y y) const
{
return std::pow(x, y);
}
};
struct lazy_ufunc_
{
template <typename F, typename A1>
struct result { typedef A1 type; };
template <typename F, typename A1>
A1 operator()(F f, A1 a1) const
{
return f(a1);
}
};
struct lazy_bfunc_
{
template <typename F, typename A1, typename A2>
struct result { typedef A1 type; };
template <typename F, typename A1, typename A2>
A1 operator()(F f, A1 a1, A2 a2) const
{
return f(a1, a2);
}
};
//} // end namespace anonymous
template <typename FPT, typename Iterator>
struct grammar
: boost::spirit::qi::grammar<
Iterator, FPT(), boost::spirit::ascii::space_type
>
{
// symbol table for constants
// to be added by the actual calculator
struct constant_
: boost::spirit::qi::symbols<
typename std::iterator_traits<Iterator>::value_type,
FPT
>
{
constant_()
{
}
} constant;
// symbol table for unary functions like "abs"
struct ufunc_
: boost::spirit::qi::symbols<
typename std::iterator_traits<Iterator>::value_type,
FPT (*)(FPT)
>
{
ufunc_()
{
this->add
("abs" , (FPT (*)(FPT)) std::abs )
("acos" , (FPT (*)(FPT)) std::acos )
("asin" , (FPT (*)(FPT)) std::asin )
("atan" , (FPT (*)(FPT)) std::atan )
("ceil" , (FPT (*)(FPT)) std::ceil )
("cos" , (FPT (*)(FPT)) std::cos )
("cosh" , (FPT (*)(FPT)) std::cosh )
("exp" , (FPT (*)(FPT)) std::exp )
("floor" , (FPT (*)(FPT)) std::floor)
("log" , (FPT (*)(FPT)) std::log )
("log10" , (FPT (*)(FPT)) std::log10)
("sin" , (FPT (*)(FPT)) std::sin )
("sinh" , (FPT (*)(FPT)) std::sinh )
("sqrt" , (FPT (*)(FPT)) std::sqrt ) ("tan" , (FPT (*)(FPT)) std::tan )
("tanh" , (FPT (*)(FPT)) std::tanh )
;
}
} ufunc;
// symbol table for binary functions like "pow"
struct bfunc_
: boost::spirit::qi::symbols<
typename std::iterator_traits<Iterator>::value_type,
FPT (*)(FPT, FPT)
>
{
bfunc_()
{
using boost::bind;
this->add
("pow" , (FPT (*)(FPT, FPT)) std::pow )
("atan2", (FPT (*)(FPT, FPT)) std::atan2)
("min" , (FPT (*)(FPT, FPT)) min_glue)
("max" , (FPT (*)(FPT, FPT)) max_glue)
;
}
} bfunc;
boost::spirit::qi::rule<
Iterator, FPT(), boost::spirit::ascii::space_type
> expression, term, factor, primary;
grammar() : grammar::base_type(expression)
{
using boost::spirit::qi::real_parser;
using boost::spirit::qi::real_policies;
real_parser<FPT,real_policies<FPT> > real;
using boost::spirit::qi::_1;
using boost::spirit::qi::_2;
using boost::spirit::qi::_3;
using boost::spirit::qi::no_case;
using boost::spirit::qi::_val;
boost::phoenix::function<lazy_pow_> lazy_pow;
boost::phoenix::function<lazy_ufunc_> lazy_ufunc;
boost::phoenix::function<lazy_bfunc_> lazy_bfunc;
expression =
term [_val = _1]
>> *( ('+' >> term [_val += _1])
| ('-' >> term [_val -= _1])
)
;
term =
factor [_val = _1]
>> *( ('*' >> factor [_val *= _1])
| ('/' >> factor [_val /= _1])
)
;
factor =
primary [_val = _1]
>> *( ("**" >> factor [_val = lazy_pow(_val, _1)])
)
;
primary =
real [_val = _1]
| '(' >> expression [_val = _1] >> ')'
| ('-' >> primary [_val = -_1])
| ('+' >> primary [_val = _1]) | (no_case[ufunc] >> '(' >> expression >> ')')
[_val = lazy_ufunc(_1, _2)]
| (no_case[bfunc] >> '(' >> expression >> ','
>> expression >> ')')
[_val = lazy_bfunc(_1, _2, _3)]
| no_case[constant] [_val = _1]
;
}
};
template <typename FPT, typename Iterator>
bool parse(Iterator &iter,
Iterator end,
const grammar<FPT,Iterator> &g,
FPT &result)
{
return boost::spirit::qi::phrase_parse(
iter, end, g, boost::spirit::ascii::space, result);
}
} // end namespace expression
#endif // LL_CALCPARSER_H