JShellParser.cc

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#include <iostream>
#include <iomanip>
#include <string>
#include <cstring>
#include <list>

#include "JLang/JNullType.hh"
#include "JLang/JEquation.hh"
#include "JLang/JEquationFacet.hh"
#include "JLang/JException.hh"
#include "JLang/JRedirectStream.hh"
#include "JLang/JLangToolkit.hh"
#include "JSystem/JSystemToolkit.hh"
#include "Jeep/JParser.hh"


/**
 * \author mdejong
 */

namespace {

  using namespace JPP;
  

  /**
   * Auxiliary class for environment variable.
   */
  template<class T>
  struct JParameter {
    /**
     * Constructor.
     *
     * \param  variable             environment variable
     */
    JParameter(const std::string& variable = "") :
      name (variable),
      value()
    {}


    /**
     * Equals operator.
     *
     * \param  first                first  parameter
     * \param  second               second parameter
     * \return                      true if first parameter equals second parameter; else false
     */
    friend bool operator==(const JParameter& first, const JParameter& second)
    {
      return (first.name  == second.name &&
              first.value == second.value);
    }


    /**
     * Stream input.
     *
     * Note that only the value of the parameter is read.
     *
     * \param  in                   input stream
     * \return                      input stream
     */
    inline std::istream& read(std::istream& in)
    {
      return in >> this->value;
    }


    /**
     * Stream output.
     *
     * Note that only the value of the parameter is written.
     *
     * \param  out                  output stream
     * \return                      output stream
     */
    inline std::ostream& write(std::ostream& out) const
    {
      return out << this->value;
    }
      
    std::string   name;             //!< environment variable name
    T             value;            //!< environment variable value
  };


  /**
   * Template specialisation of JParameter<std::string>::read.
   *
   * \param  in          input stream
   * \return             input stream
   */
  template<>
  inline std::istream& JParameter<std::string>::read(std::istream& in)
  {
    return std::getline(in, this->value);
  }


  /**
   * Template specialisation of JParameter<bool>::read.
   *
   * \param  in          input stream
   * \return             input stream
   */
  template<>
  inline std::istream& JParameter<bool>::read(std::istream& in)
  {
    this->value = true;
    
    return in;
  }


  /**
   * Template specialisation of JParameter<bool>::write.
   *
   * \param  out         output stream
   * \return             output stream
   */
  template<>
  inline std::ostream& JParameter<bool>::write(std::ostream& out) const
  {
    return out << (this->value ? "1" : "0");
  }


  /**
   * Stream input of parameter.
   *
   * \param  in                   input stream
   * \param  parameter            parameter
   * \return                      input stream
   */
  template<class T>
  inline std::istream& operator>>(std::istream& in, JParameter<T>& parameter)
  {
    return parameter.read(in);
  }
  
  
  /**
   * Stream output of parameter.
   *
   * \param  out                  output stream
   * \param  parameter            parameter
   * \return                      output stream
   */
  template<class T>
  inline std::ostream& operator<<(std::ostream& out, const JParameter<T>& parameter)
  {
    return parameter.write(out);
  }
  

  /**
   * Parser for environment variables.
   */
  template<class T = JNullType>
  struct JEnvironment;

  
  /**
   * Base class for environment variables.
   */
  template<>
  struct JEnvironment<JNullType> :
    public JParser<>
  {
    typedef JParser<>::key_type                      key_type;


    /**
     * Default constructor.
     */
    JEnvironment() 
    {}


    /**
     * Join environment.
     *
     * \param  environment          environment
     * \return                      this environment
     */
    JEnvironment join(const JEnvironment& environment)
    {
      this->insert(environment.begin(), environment.end());

      return *this;
    }
      

    /**
     * Process command line arguments.
     *
     * \param  argc                 number of command line arguments
     * \param  argv                 array  of command line arguments
     * \return                      status (0 = OK)
     */
    int operator()(int argc, char** argv)
    {
      using namespace std;
      using namespace JPP;
      
      // look for pending command line arguments
      
      for ( ; argc != 0 && strcmp(*argv, "--") != 0; --argc, ++argv) {}

      int           status = -1;
      ostringstream os;

      {
        JRedirectStream redirect[] = { JRedirectStream(cout, os),
                                       JRedirectStream(cerr, os) };

        if (redirect[0] &&
            redirect[1]) {
          status = this->read(argc, argv);
        }
      }
      
      gprint(os.str());
      
      return status;
    }
  };

  
  /**
   * Template specialisation of JEnvironment for regular environment variables.
   */
  template<>
  struct JEnvironment<std::string> :
    public JEnvironment<>
  {
    typedef JParser<>::key_type                        key_type;
    typedef JParameter<std::string>                    parameter_type;
    typedef std::list<parameter_type>::const_iterator  const_iterator;


    /**
     * Default constructor.
     */
    JEnvironment() 
    {}


    /**
     * Stream input.
     *
     * \param  in                   input stream
     * \param  environment          environment
     * \return                      input stream
     */
    friend inline std::istream& operator>>(std::istream& in, JEnvironment& environment)
    {
      using namespace std;
      using namespace JPP;

      static const JEquationFacet facet(JEquationParameters("=", ";\n", "./", "#"));

      char       c;
      key_type   key;
      JEquation  equation;

      if (!has_facet<JEquationFacet>(in.getloc())) {
        in.imbue(locale(in.getloc(), facet.clone()));
      }

      if (in >> c >> key >> equation) {

        if (c == '-' && !equation.getKey().empty()) {

          environment.data.push_back(parameter_type(equation.getKey()));

          parameter_type& parameter = environment.data.back();

          if (facet.isSeparator(equation.getSeparator())) {

            // read possible values
            
            istringstream is(equation.getValue());

            vector<parameter_type> possible_values;
            
            for (parameter_type buffer(parameter.name); getline(is, buffer.value, ','); ) {

              buffer.value = trim(buffer.value);

              possible_values.push_back(buffer);
            }
            
            environment[key] = JPARSER::getOption(parameter, equation.getKey(), possible_values.begin(), possible_values.end());

          } else {

            environment[key] = JPARSER::getOption(parameter, equation.getKey());
          }

        } else {

          THROW(JParseError, "JEnvironment: error parsing " << c << " <" << equation.getKey() << ">");
        }
      }

      return in;
    }

    
    std::list<parameter_type> data;     //!< internal memory
  };


  /**
   * Template specialisation of JEnvironment for boolean environment variables.
   */
  template<>
  struct JEnvironment<bool> :
    public JEnvironment<>
  {
    typedef JParser<>::key_type                        key_type;
    typedef JParameter<bool>                           parameter_type;
    typedef std::list<parameter_type>::const_iterator  const_iterator;
    

    /**
     * Default constructor.
     */
    JEnvironment() 
    {}


    /**
     * Stream input.
     *
     * \param  in                   input stream
     * \param  environment          environment
     * \return                      input stream
     */
    friend inline std::istream& operator>>(std::istream& in, JEnvironment& environment)
    {
      using namespace std;
      using namespace JPP;

      static const JEquationFacet facet(JEquationParameters("=", ";\n", "./", "#"));

      char       c;
      key_type   key;
      JEquation  equation;

      if (!has_facet<JEquationFacet>(in.getloc())) {
        in.imbue(locale(in.getloc(), facet.clone()));
      }

      if (in >> c >> key >> equation) {

        if (c == '-' && !equation.getKey().empty()) {

          environment.data.push_back(parameter_type(equation.getKey()));

          parameter_type& parameter = environment.data.back();
          
          if (facet.isSeparator(equation.getSeparator()) || equation.getValue() != "") {

            THROW(JParseError, "JEnvironment: invalid operation " << c << " <" << equation.getKey() << ">");
          
          } else {

            environment[key] = JPARSER::getOption(parameter.value, equation.getKey());
          }

        } else {

          THROW(JParseError, "JEnvironment: error parsing " << c << " <" << equation.getKey() << ">");
        }
      }

      return in;
    }


    std::list<parameter_type> data;     //!< internal memory
  };

  
  /**
   * Evaluate environment to shell commands.
   *
   * \param  environment          environment
   */
  template<class T>
  void evaluate(const JEnvironment<T>& environment)
  {
    using namespace std;
          
    for (typename JEnvironment<T>::const_iterator i = environment.data.begin(); i != environment.data.end(); ++i) {

      stringbuf buffer;

      ostream os(&buffer);

      os << *i;

      set_variable(i->name, buffer.str());
    }
  }
}


/**
 * Auxiliary program to interface JPARSER::JParser to command line of shell scripts.
 * Syntax:
 * <pre>
 *   eval `JShellParser -o "-a <environment variable> [= <default value>[, <possible value>]]" -- $*`
 * </pre>
 */
int main(int argc, char **argv)
{
  using namespace std;

  int debug;
  
  try {

    JEnvironment<bool>   boolean;
    JEnvironment<string> regular;

    JParser<> zap("Auxiliary program to interface C++ parser to command line of shell scripts.");
    
    zap['b'] = make_field(boolean) = JPARSER::initialised();
    zap['o'] = make_field(regular) = JPARSER::initialised();
    zap['d'] = make_field(debug)   = 1;

    if (zap.read(argc, argv) != 0) {
      return gexit(1);
    }

    JEnvironment<> buffer;

    JEnvironment<>::debug = debug;

    buffer.join(boolean);
    buffer.join(regular);

    if (buffer(argc, argv) == 0) { 
      evaluate(boolean);
      evaluate(regular);
    } else {
      gexit(1);
    }
  }
  catch(const exception& error) {
    return gexit(2, error.what());
  }
}