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 22 of file Parser.h.

Member Function Documentation

eval()

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

virtual

Definition at line 29 of file Parser.C.

{
  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.emplace_back(
        "fparse error: " + std::string(fp.ErrorMsg()) + " in '" + n->fullpath() + "'", n);
    return n->val();
  }

  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.emplace_back("no variable '" + var +
                                  "' found for use in function parser expression in '" +
                                  n->fullpath() + "'",
                              n);
  }

  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 files:

• include/parser/Parser.h
• src/parser/Parser.C