flowCoef.cc

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/*
  @copyright Steve Keen 2013
  @author Russell Standish
  This file is part of Minsky.

  Minsky is free software: you can redistribute it and/or modify it
  under the terms of the GNU General Public License as published by
  the Free Software Foundation, either version 3 of the License, or
  (at your option) any later version.

  Minsky 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 General Public License for more details.

  You should have received a copy of the GNU General Public License
  along with Minsky.  If not, see <http://www.gnu.org/licenses/>.
*/

#include "flowCoef.h"
#include "str.h"
#include "minsky_epilogue.h"
#include <ctype.h>
#include <stdlib.h>
#include <boost/spirit/include/qi.hpp>
namespace qi = boost::spirit::qi;

using namespace std;

namespace
{
  // Extract leading number from a string. for ticket 1177. See https://stackoverflow.com/questions/45600212/regular-expression-multiple-floating-point.
  bool parseLine(std::string const& line, std::string& pref) {
     using it = std::string::const_iterator;    
     
     // Construct grammar to treat inf and nan separately in input formula. See https://www.boost.org/doc/libs/1_68_0/libs/spirit/doc/html/spirit/qi/reference/numeric/real.html
     qi::rule<it, std::string()> nan = -qi::lit("1.0#") >> qi::no_case["nan"] >> -('(' >> *(qi::char_ - ')') >> ')');
     qi::rule<it, std::string()> inf = qi::no_case[qi::lit("inf") >> -qi::lit("inity")];
     qi::rule<it, std::string()> sign = qi::lit('+') | '-';
    
     
     it first = line.begin(), last = line.end();
     return (qi::phrase_parse(first, last, -sign >> ( inf | nan) ,qi::blank, pref));
  }
}

namespace minsky
{
  FlowCoef::FlowCoef(const string& formula)
  {
      const char* f=formula.c_str();
      char* tail;
      std::string prefix;  
      
      // If NaN or inf appear in any form or case in the name of a flow coefficient, tail is set equal to f. For ticket 1177.
      if (parseLine(formula, prefix)) {
         tail=(char*)f;
          } else coef=strtod(f,&tail);  
      
      if (tail==f) // oops, that failed, check if there's a leading - sign
        {
          // skip whitespace
          while (*tail != '\0' && isspace(*tail)) ++tail;
          if (*tail=='\0') 
            {
              coef=0;
              return; // empty cell, nothing to do
            }
          if (*tail=='-') 
            {
              coef=-1; // treat leading - sign as -1
              tail++;
            }
          else
            coef=1;
        }

      name=trimWS(tail);
  }

  string FlowCoef::str() const
  {
    if (name.empty())
      return minsky::str(coef);
    if (coef==1)
      return name;
    if (coef==-1)
      return "-"+name;
    return minsky::str(coef)+name;
  }

}