FuncParseEvaler Class Reference

#include <Parser.h>

Inheritance diagram for FuncParseEvaler:

Public Member Functions
virtual std::string	eval (hit::Field *n, const std::list< std::string > &args, hit::BraceExpander &exp)

Detailed Description

Definition at line 33 of file Parser.h.

Member Function Documentation

eval()

virtual std::string FuncParseEvaler::eval ( hit::Field *  n, const std::list< std::string > &  args, hit::BraceExpander &  exp  )

inlinevirtual

Definition at line 37 of file Parser.h.

  {
    std::string func_text;
    for (auto & s : args)
      func_text += s;
    auto n_errs = exp.errors.size();
 
    FunctionParser fp;
    fp.AddConstant("pi", libMesh::pi);
    fp.AddConstant("e", std::exp(Real(1)));
    std::vector<std::string> var_names;
    auto ret = fp.ParseAndDeduceVariables(func_text, var_names);
    if (ret != -1)
    {
      exp.errors.push_back(hit::errormsg(exp.fname, n, "fparse error: ", fp.ErrorMsg()));
      return n->val();
    }
 
    std::string errors;
    std::vector<double> var_vals;
    for (auto & var : var_names)
    {
      // recursively check all parent scopes for the needed variables
      hit::Node * curr = n;
      while ((curr = curr->parent()))
      {
        auto src = curr->find(var);
        if (src && src != n && src->type() == hit::NodeType::Field)
        {
          exp.used.push_back(hit::pathJoin({curr->fullpath(), var}));
          var_vals.push_back(curr->param<double>(var));
          break;
        }
      }
 
      if (curr == nullptr)
        exp.errors.push_back(hit::errormsg(exp.fname,
                                           n,
                                           "\n    no variable '",
                                           var,
                                           "' found for use in function parser expression"));
    }
 
    if (exp.errors.size() != n_errs)
      return n->val();
 
    std::stringstream ss;
    ss << std::setprecision(17) << fp.Eval(var_vals.data());
 
    // change kind only (not val)
    n->setVal(n->val(), hit::Field::Kind::Float);
    return ss.str();
  }

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The documentation for this class was generated from the following file:

• include/parser/Parser.h