compiler/cpp/src/generate/t_ocaml_generator.cc

/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements. See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership. The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License. You may obtain a copy of the License at
 *
 *   http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied. See the License for the
 * specific language governing permissions and limitations
 * under the License.
 */

#include <string>
#include <fstream>
#include <iostream>
#include <vector>

#include <stdlib.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <sstream>
#include "t_oop_generator.h"
#include "platform.h"
#include "version.h"

using namespace std;


/**
 * OCaml code generator.
 *
 */
class t_ocaml_generator : public t_oop_generator {
 public:
  t_ocaml_generator(
      t_program* program,
      const std::map<std::string, std::string>& parsed_options,
      const std::string& option_string)
    : t_oop_generator(program)
  {
    (void) parsed_options;
    (void) option_string;
    out_dir_base_ = "gen-ocaml";
  }

  /**
   * Init and close methods
   */

  void init_generator();
  void close_generator();

  /**
   * Program-level generation functions
   */
  void generate_program  ();
  void generate_typedef  (t_typedef*  ttypedef);
  void generate_enum     (t_enum*     tenum);
  void generate_const    (t_const*    tconst);
  void generate_struct   (t_struct*   tstruct);
  void generate_xception (t_struct*   txception);
  void generate_service  (t_service*  tservice);

  std::string render_const_value(t_type* type, t_const_value* value);
  bool struct_member_persistent(t_field *tmember);
  bool struct_member_omitable(t_field *tmember);
  bool struct_member_default_cheaply_comparable(t_field *tmember);
  std::string struct_member_copy_of(t_type *type, string what);

  /**
   * Struct generation code
   */

  void generate_ocaml_struct(t_struct* tstruct, bool is_exception);
  void generate_ocaml_struct_definition(std::ofstream& out, t_struct* tstruct, bool is_xception=false);
  void generate_ocaml_struct_member(std::ofstream& out, string tname, t_field* tmember);
  void generate_ocaml_struct_sig(std::ofstream& out, t_struct* tstruct, bool is_exception);
  void generate_ocaml_struct_reader(std::ofstream& out, t_struct* tstruct);
  void generate_ocaml_struct_writer(std::ofstream& out, t_struct* tstruct);
  void generate_ocaml_function_helpers(t_function* tfunction);
  void generate_ocaml_method_copy(std::ofstream& out, const vector<t_field *>& members);
  void generate_ocaml_member_copy(std::ofstream& out, t_field *member);

  /**
   * Service-level generation functions
   */

  void generate_service_helpers   (t_service*  tservice);
  void generate_service_interface (t_service* tservice);
  void generate_service_client    (t_service* tservice);
  void generate_service_server    (t_service* tservice);
  void generate_process_function  (t_service* tservice, t_function* tfunction);

  /**
   * Serialization constructs
   */

  void generate_deserialize_field        (std::ofstream &out,
                                          t_field*    tfield,
                                          std::string prefix);

  void generate_deserialize_struct       (std::ofstream &out,
                                          t_struct*   tstruct);

  void generate_deserialize_container    (std::ofstream &out,
                                          t_type*     ttype);

  void generate_deserialize_set_element  (std::ofstream &out,
                                          t_set*      tset);


  void generate_deserialize_list_element (std::ofstream &out,
                                          t_list*     tlist,
                                          std::string prefix="");
  void generate_deserialize_type          (std::ofstream &out,
                                           t_type* type);

  void generate_serialize_field          (std::ofstream &out,
                                          t_field*    tfield,
                                          std::string name= "");

  void generate_serialize_struct         (std::ofstream &out,
                                          t_struct*   tstruct,
                                          std::string prefix="");

  void generate_serialize_container      (std::ofstream &out,
                                          t_type*     ttype,
                                          std::string prefix="");

  void generate_serialize_map_element    (std::ofstream &out,
                                          t_map*      tmap,
                                          std::string kiter,
                                          std::string viter);

  void generate_serialize_set_element    (std::ofstream &out,
                                          t_set*      tmap,
                                          std::string iter);

  void generate_serialize_list_element   (std::ofstream &out,
                                          t_list*     tlist,
                                          std::string iter);

  /**
   * Helper rendering functions
   */

  std::string ocaml_autogen_comment();
  std::string ocaml_imports();
  std::string type_name(t_type* ttype);
  std::string function_signature(t_function* tfunction, std::string prefix="");
  std::string function_type(t_function* tfunc, bool method=false, bool options = false);
  std::string argument_list(t_struct* tstruct);
  std::string type_to_enum(t_type* ttype);
  std::string render_ocaml_type(t_type* type);


 private:

  /**
   * File streams
   */

  std::ofstream f_types_;
  std::ofstream f_consts_;
  std::ofstream f_service_;

  std::ofstream f_types_i_;
  std::ofstream f_service_i_;

};


/*
 * This is necessary because we want typedefs to appear later,
 * after all the types have been declared.
 */
void t_ocaml_generator::generate_program() {
  // Initialize the generator
  init_generator();

  // Generate enums
  vector<t_enum*> enums = program_->get_enums();
  vector<t_enum*>::iterator en_iter;
  for (en_iter = enums.begin(); en_iter != enums.end(); ++en_iter) {
    generate_enum(*en_iter);
  }

  // Generate structs
  vector<t_struct*> structs = program_->get_structs();
  vector<t_struct*>::iterator st_iter;
  for (st_iter = structs.begin(); st_iter != structs.end(); ++st_iter) {
    generate_struct(*st_iter);
  }

  // Generate xceptions
  vector<t_struct*> xceptions = program_->get_xceptions();
  vector<t_struct*>::iterator x_iter;
  for (x_iter = xceptions.begin(); x_iter != xceptions.end(); ++x_iter) {
    generate_xception(*x_iter);
  }

  // Generate typedefs
  vector<t_typedef*> typedefs = program_->get_typedefs();
  vector<t_typedef*>::iterator td_iter;
  for (td_iter = typedefs.begin(); td_iter != typedefs.end(); ++td_iter) {
    generate_typedef(*td_iter);
  }

  // Generate services
  vector<t_service*> services = program_->get_services();
  vector<t_service*>::iterator sv_iter;
  for (sv_iter = services.begin(); sv_iter != services.end(); ++sv_iter) {
    service_name_ = get_service_name(*sv_iter);
    generate_service(*sv_iter);
  }

  // Generate constants
  vector<t_const*> consts = program_->get_consts();
  generate_consts(consts);

  // Close the generator
  close_generator();
}


/**
 * Prepares for file generation by opening up the necessary file output
 * streams.
 *
 * @param tprogram The program to generate
 */
void t_ocaml_generator::init_generator() {
  // Make output directory
  MKDIR(get_out_dir().c_str());

  // Make output file
  string f_types_name = get_out_dir()+program_name_+"_types.ml";
  f_types_.open(f_types_name.c_str());
  string f_types_i_name = get_out_dir()+program_name_+"_types.mli";
  f_types_i_.open(f_types_i_name.c_str());

  string f_consts_name = get_out_dir()+program_name_+"_consts.ml";
  f_consts_.open(f_consts_name.c_str());

  // Print header
  f_types_ <<
    ocaml_autogen_comment() << endl <<
    ocaml_imports() << endl;
  f_types_i_ <<
    ocaml_autogen_comment() << endl <<
    ocaml_imports() << endl;
  f_consts_ <<
    ocaml_autogen_comment() << endl <<
    ocaml_imports() << endl <<
    "open " << capitalize(program_name_)<<"_types"<< endl;
}


/**
 * Autogen'd comment
 */
string t_ocaml_generator::ocaml_autogen_comment() {
  return
    std::string("(*\n") +
    " Autogenerated by Thrift Compiler (" + THRIFT_VERSION + ")\n" +
    "\n" +
    " DO NOT EDIT UNLESS YOU ARE SURE YOU KNOW WHAT YOU ARE DOING\n" +
    "*)\n";
}

/**
 * Prints standard thrift imports
 */
string t_ocaml_generator::ocaml_imports() {
  return "open Thrift";
}

/**
 * Closes the type files
 */
void t_ocaml_generator::close_generator() {
  // Close types file
  f_types_.close();
}

/**
 * Generates a typedef. Ez.
 *
 * @param ttypedef The type definition
 */
void t_ocaml_generator::generate_typedef(t_typedef* ttypedef) {
  f_types_ <<
    indent() << "type "<< decapitalize(ttypedef->get_symbolic()) << " = " << render_ocaml_type(ttypedef->get_type()) << endl << endl;
  f_types_i_ <<
    indent() << "type "<< decapitalize(ttypedef->get_symbolic()) << " = " << render_ocaml_type(ttypedef->get_type()) << endl << endl;
}

/**
 * Generates code for an enumerated type.
 * the values.
 *
 * @param tenum The enumeration
 */
void t_ocaml_generator::generate_enum(t_enum* tenum) {
  indent(f_types_) << "module " << capitalize(tenum->get_name()) << " = " << endl << "struct" << endl;
  indent(f_types_i_) << "module " << capitalize(tenum->get_name()) << " : " << endl << "sig" << endl;
  indent_up();
  indent(f_types_) << "type t = " << endl;
  indent(f_types_i_) << "type t = " << endl;
  indent_up();
  vector<t_enum_value*> constants = tenum->get_constants();
  vector<t_enum_value*>::iterator c_iter;
  for (c_iter = constants.begin(); c_iter != constants.end(); ++c_iter) {
    string name = capitalize((*c_iter)->get_name());
    indent(f_types_) << "| " << name << endl;
    indent(f_types_i_) << "| " << name << endl;
  }
  indent_down();

  indent(f_types_) << "let to_i = function" << endl;
  indent(f_types_i_) << "val to_i : t -> Int32.t" << endl;
  indent_up();
  for (c_iter = constants.begin(); c_iter != constants.end(); ++c_iter) {
    int value = (*c_iter)->get_value();
    string name = capitalize((*c_iter)->get_name());
    indent(f_types_) << "| " << name << " -> " << value << "l" << endl;
  }
  indent_down();

  indent(f_types_) << "let of_i = function" << endl;
  indent(f_types_i_) << "val of_i : Int32.t -> t" << endl;
  indent_up();
  for(c_iter = constants.begin(); c_iter != constants.end(); ++c_iter) {
    int value = (*c_iter)->get_value();
    string name = capitalize((*c_iter)->get_name());
    indent(f_types_) << "| " << value << "l -> " << name << endl;
  }
  indent(f_types_) << "| _ -> raise Thrift_error" << endl;
  indent_down();
  indent_down();
  indent(f_types_) << "end" << endl;
  indent(f_types_i_) << "end" << endl;
}

/**
 * Generate a constant value
 */
void t_ocaml_generator::generate_const(t_const* tconst) {
  t_type* type = tconst->get_type();
  string name = decapitalize(tconst->get_name());
  t_const_value* value = tconst->get_value();

  indent(f_consts_) << "let " << name << " = " << render_const_value(type, value) << endl << endl;
}

/**
 * Prints the value of a constant with the given type. Note that type checking
 * is NOT performed in this function as it is always run beforehand using the
 * validate_types method in main.cc
 */
string t_ocaml_generator::render_const_value(t_type* type, t_const_value* value) {
  type = get_true_type(type);
  std::ostringstream out;
  // OCaml requires all floating point numbers contain a decimal point
  out.setf(ios::showpoint);
  if (type->is_base_type()) {
    t_base_type::t_base tbase = ((t_base_type*)type)->get_base();
    switch (tbase) {
    case t_base_type::TYPE_STRING:
      out << '"' << get_escaped_string(value) << '"';
      break;
    case t_base_type::TYPE_BOOL:
      out << (value->get_integer() > 0 ? "true" : "false");
      break;
    case t_base_type::TYPE_BYTE:
    case t_base_type::TYPE_I16:
      out << value->get_integer();
      break;
    case t_base_type::TYPE_I32:
      out << value->get_integer() << "l";
      break;
    case t_base_type::TYPE_I64:
      out << value->get_integer() << "L";
      break;
    case t_base_type::TYPE_DOUBLE:
      if (value->get_type() == t_const_value::CV_INTEGER) {
        out << value->get_integer() << ".0";
      } else {
        out << value->get_double();
      }
      break;
    default:
      throw "compiler error: no const of base type " + t_base_type::t_base_name(tbase);
    }
  } else if (type->is_enum()) {
    t_enum* tenum = (t_enum*)type;
    vector<t_enum_value*> constants = tenum->get_constants();
    vector<t_enum_value*>::iterator c_iter;
    for (c_iter = constants.begin(); c_iter != constants.end(); ++c_iter) {
      int val = (*c_iter)->get_value();
      if (val == value->get_integer()) {
        indent(out) << capitalize(tenum->get_name()) << "." << capitalize((*c_iter)->get_name());
        break;
      }
    }
  } else if (type->is_struct() || type->is_xception()) {
    string cname = type_name(type);
    string ct = tmp("_c");
    out << endl;
    indent_up();
    indent(out) << "(let " << ct << " = new " << cname << " in" << endl;
    indent_up();
    const vector<t_field*>& fields = ((t_struct*)type)->get_members();
    vector<t_field*>::const_iterator f_iter;
    const map<t_const_value*, t_const_value*>& val = value->get_map();
    map<t_const_value*, t_const_value*>::const_iterator v_iter;
    for (v_iter = val.begin(); v_iter != val.end(); ++v_iter) {
      t_type* field_type = NULL;
      for (f_iter = fields.begin(); f_iter != fields.end(); ++f_iter) {
        if ((*f_iter)->get_name() == v_iter->first->get_string()) {
          field_type = (*f_iter)->get_type();
        }
      }
      if (field_type == NULL) {
        throw "type error: " + type->get_name() + " has no field " + v_iter->first->get_string();
      }
      string fname = v_iter->first->get_string();
      out << indent();
      out << ct <<"#set_" << fname << " ";
      out << render_const_value(field_type, v_iter->second);
      out << ";" << endl;
    }
    indent(out) << ct << ")";
    indent_down();
    indent_down();
  } else if (type->is_map()) {
    t_type* ktype = ((t_map*)type)->get_key_type();
    t_type* vtype = ((t_map*)type)->get_val_type();
    const map<t_const_value*, t_const_value*>& val = value->get_map();
    map<t_const_value*, t_const_value*>::const_iterator v_iter;
    string hm = tmp("_hm");
    out << endl;
    indent_up();
    indent(out) << "(let " << hm << " = Hashtbl.create " << val.size() << " in" << endl;
    indent_up();
    for (v_iter = val.begin(); v_iter != val.end(); ++v_iter) {
      string key = render_const_value(ktype, v_iter->first);
      string val = render_const_value(vtype, v_iter->second);
      indent(out) << "Hashtbl.add " << hm << " " << key << " " << val << ";" << endl;
    }
    indent(out) << hm << ")";
    indent_down();
    indent_down();
  } else if (type->is_list()) {
    t_type* etype;
    etype = ((t_list*)type)->get_elem_type();
    out << "[" << endl;
    indent_up();
    const vector<t_const_value*>& val = value->get_list();
    vector<t_const_value*>::const_iterator v_iter;
    for (v_iter = val.begin(); v_iter != val.end(); ++v_iter) {
      out << indent();
      out << render_const_value(etype, *v_iter);
      out << ";" << endl;
    }
    indent_down();
    indent(out) << "]";
  } else if (type->is_set()) {
    t_type* etype = ((t_set*)type)->get_elem_type();
    const vector<t_const_value*>& val = value->get_list();
    vector<t_const_value*>::const_iterator v_iter;
    string hm = tmp("_hm");
    indent(out) << "(let " << hm << " = Hashtbl.create " << val.size() << " in" << endl;
    indent_up();
    for (v_iter = val.begin(); v_iter != val.end(); ++v_iter) {
      string val = render_const_value(etype, *v_iter);
      indent(out) << "Hashtbl.add " << hm << " " << val << " true;" << endl;
    }
    indent(out) << hm << ")" << endl;
    indent_down();
    out << endl;
  } else {
    throw "CANNOT GENERATE CONSTANT FOR TYPE: " + type->get_name();
  }
  return out.str();
}

/**
 * Generates a "struct"
 */
void t_ocaml_generator::generate_struct(t_struct* tstruct) {
  generate_ocaml_struct(tstruct, false);
}

/**
 * Generates a struct definition for a thrift exception. Basically the same
 * as a struct, but also has an exception declaration.
 *
 * @param txception The struct definition
 */
void t_ocaml_generator::generate_xception(t_struct* txception) {
  generate_ocaml_struct(txception, true);
}

/**
 * Generates an OCaml struct
 */
void t_ocaml_generator::generate_ocaml_struct(t_struct* tstruct,
                                              bool is_exception) {
  generate_ocaml_struct_definition(f_types_, tstruct, is_exception);
  generate_ocaml_struct_sig(f_types_i_,tstruct,is_exception);
}

void t_ocaml_generator::generate_ocaml_method_copy(ofstream& out,
                                                   const vector<t_field *>& members) {
    vector<t_field*>::const_iterator m_iter;

    /* Create a copy of the current object */
    indent(out) << "method copy =" << endl;
    indent_up(); indent_up();
    indent(out) << "let _new = Oo.copy self in" << endl;
    for (m_iter = members.begin(); m_iter != members.end(); ++m_iter)
        generate_ocaml_member_copy(out, *m_iter);

    indent_down();
    indent(out) << "_new" << endl;
    indent_down();
}

string t_ocaml_generator::struct_member_copy_of(t_type *type, string what) {
    if (type->is_struct() || type->is_xception()) {
        return what + string ("#copy");
    } if (type->is_map()) {
        string copy_of_k = struct_member_copy_of(((t_map *)type)->get_key_type(), "k");
        string copy_of_v = struct_member_copy_of(((t_map *)type)->get_val_type(), "v");

        if(copy_of_k == "k" && copy_of_v == "v") {
                return string ("(Hashtbl.copy ") + what + string(")");
        } else {
                return string ("((fun oh -> let nh = Hashtbl.create (Hashtbl.length oh) in Hashtbl.iter (fun k v -> Hashtbl.add nh ")
                    + copy_of_k + string(" ") + copy_of_v
                    + string(") oh; nh) ")
                    + what + ")";
        }
    } if (type->is_set()) {
        string copy_of = struct_member_copy_of(((t_set *)type)->get_elem_type(), "k");

        if(copy_of == "k") {
                return string ("(Hashtbl.copy ") + what + string(")");
        } else {
                return string ("((fun oh -> let nh = Hashtbl.create (Hashtbl.length oh) in Hashtbl.iter (fun k v -> Hashtbl.add nh ")
                    + copy_of + string(" true")
                    + string(") oh; nh) ")
                    + what + ")";
        }
    } if (type->is_list()) {
        string copy_of = struct_member_copy_of(((t_list *)type)->get_elem_type(), "x");
        if(copy_of != "x") {
            return string("(List.map (fun x -> ")
                + copy_of + string (") ")
                + what + string(")");
        } else {
            return what;
        }
    }
    return what;
}

void t_ocaml_generator::generate_ocaml_member_copy(ofstream& out,
                                                   t_field *tmember) {
    string mname = decapitalize(tmember->get_name());
    t_type* type = get_true_type(tmember->get_type());

    string grab_field = string("self#grab_") + mname;
    string copy_of = struct_member_copy_of(type, grab_field);
    if(copy_of != grab_field) {
        indent(out);
        if(!struct_member_persistent(tmember)) {
                out << "if _" << mname << " <> None then" << endl;
                indent(out) << "  ";
        }
        out << "_new#set_" << mname << " " << copy_of << ";" << endl;
    }
}

/**
 * Generates a struct definition for a thrift data type.
 *
 * @param tstruct The struct definition
 */
void t_ocaml_generator::generate_ocaml_struct_definition(ofstream& out,
                                                         t_struct* tstruct,
                                                         bool is_exception) {
  const vector<t_field*>& members = tstruct->get_members();
  vector<t_field*>::const_iterator m_iter;
  string tname = type_name(tstruct);
  indent(out) << "class " << tname << " =" << endl;
  indent(out) << "object (self)" << endl;

  indent_up();

  if (members.size() > 0) {
    for (m_iter = members.begin(); m_iter != members.end(); ++m_iter) {
      generate_ocaml_struct_member(out, tname, (*m_iter));
      out << endl;
    }
  }
  generate_ocaml_method_copy(out, members);
  generate_ocaml_struct_writer(out, tstruct);
  indent_down();
  indent(out) << "end" << endl;

  if(is_exception){
    indent(out) << "exception " << capitalize(tname) <<" of " << tname << endl;
  }

  generate_ocaml_struct_reader(out, tstruct);
}

/**
 * Generates a structure member for a thrift data type.
 *
 * @param tname Name of the parent structure for the member
 * @param tmember Member definition
 */
void t_ocaml_generator::generate_ocaml_struct_member(ofstream& out,
                                                     string tname,
                                                     t_field* tmember) {
  string x = tmp("_x");
  string mname = decapitalize(tmember->get_name());

  indent(out) << "val mutable _" << mname << " : " << render_ocaml_type(tmember->get_type());
  t_const_value *val = tmember->get_value();
  if(val) {
    if(struct_member_persistent(tmember))
        out << " = " << render_const_value(tmember->get_type(), tmember->get_value()) << endl;
    else
        out << " option = Some " << render_const_value(tmember->get_type(), tmember->get_value()) << endl;
  } else {
    // assert(!struct_member_persistent(tmember))
    out << " option = None" << endl;
  }

  if(struct_member_persistent(tmember)) {
        indent(out) << "method get_" << mname << " = Some _" << mname << endl;
        indent(out) << "method grab_" << mname << " = _" << mname << endl;
        indent(out) << "method set_" << mname << " " << x << " = _" << mname << " <- " << x << endl;
  } else {
        indent(out) << "method get_" << mname << " = _" << mname << endl;
        indent(out) << "method grab_" << mname << " = match _"<<mname<<" with None->raise (Field_empty \""<<tname<<"."<<mname<<"\") | Some " << x <<" -> " << x << endl;
        indent(out) << "method set_" << mname << " " << x << " = _" << mname << " <- Some " << x << endl;
        indent(out) << "method unset_" << mname << " = _" << mname << " <- None" << endl;
  }

  indent(out) << "method reset_" << mname << " = _" << mname << " <- ";
  if(val) {
    if(struct_member_persistent(tmember))
        out << render_const_value(tmember->get_type(), tmember->get_value()) << endl;
    else
        out << "Some " << render_const_value(tmember->get_type(), tmember->get_value()) << endl;
  } else {
    out << "None" << endl;
  }


}

/**
 * Check whether a member of the structure can not have undefined value
 *
 * @param tmember Member definition
 */
bool t_ocaml_generator::struct_member_persistent(t_field *tmember) {
  t_const_value *val = tmember->get_value();
  return (val ? true : false);
}

/**
 * Check whether a member of the structure can be skipped during encoding
 *
 * @param tmember Member definition
 */
bool t_ocaml_generator::struct_member_omitable(t_field *tmember) {
  return (tmember->get_req() != t_field::T_REQUIRED);
}

/**
 * Figure out whether a member of the structure has
 * a cheaply comparable default value.
 *
 * @param tmember Member definition
 */
bool t_ocaml_generator::struct_member_default_cheaply_comparable(t_field *tmember) {
  t_type* type = get_true_type(tmember->get_type());
  t_const_value *val = tmember->get_value();
  if(!val) {
    return false;
  } else if(type->is_base_type()) {
    // Base types are generally cheaply compared for structural equivalence.
    switch(((t_base_type*)type)->get_base()) {
    case t_base_type::TYPE_DOUBLE:
        if(val->get_double() == 0.0)
                return true;
        else
                return false;
    default:
        return true;
    }
  } else if(type->is_list()) {
    // Empty lists are cheaply compared for structural equivalence.
    // Is empty list?
    if(val->get_list().size() == 0)
        return true;
    else
        return false;
  } else {
    return false;
  }
}

/**
 * Generates a struct definition for a thrift data type.
 *
 * @param tstruct The struct definition
 */
void t_ocaml_generator::generate_ocaml_struct_sig(ofstream& out,
                                                  t_struct* tstruct,
                                                  bool is_exception) {
  const vector<t_field*>& members = tstruct->get_members();
  vector<t_field*>::const_iterator m_iter;
  string tname = type_name(tstruct);
  indent(out) << "class " << tname << " :" << endl;
  indent(out) << "object ('a)" << endl;

  indent_up();

  string x = tmp("_x");
  if (members.size() > 0) {
    for (m_iter = members.begin(); m_iter != members.end(); ++m_iter) {
      string mname = decapitalize((*m_iter)->get_name());
      string type = render_ocaml_type((*m_iter)->get_type());
      indent(out) << "method get_" << mname << " : " << type << " option" << endl;
      indent(out) << "method grab_" << mname << " : " << type << endl;
      indent(out) << "method set_" << mname << " : " << type << " -> unit" << endl;
      if(!struct_member_persistent(*m_iter))
        indent(out) << "method unset_" << mname << " : unit" << endl;
      indent(out) << "method reset_" << mname << " : unit" << endl;
    }
  }
  indent(out) << "method copy : 'a" << endl;
  indent(out) << "method write : Protocol.t -> unit" << endl;
  indent_down();
  indent(out) << "end" << endl;

  if(is_exception){
    indent(out) << "exception " << capitalize(tname) <<" of " << tname << endl;
  }

  indent(out) << "val read_" << tname << " : Protocol.t -> " << tname << endl;
}

/**
 * Generates the read method for a struct
 */
void t_ocaml_generator::generate_ocaml_struct_reader(ofstream& out, t_struct* tstruct) {
  const vector<t_field*>& fields = tstruct->get_members();
  vector<t_field*>::const_iterator f_iter;
  string sname = type_name(tstruct);
  string str = tmp("_str");
  string t = tmp("_t");
  string id = tmp("_id");
  indent(out) <<
    "let rec read_" << sname << " (iprot : Protocol.t) =" << endl;
  indent_up();
  indent(out) << "let " << str << " = new " << sname << " in" << endl;
  indent_up();
  indent(out) <<
    "ignore(iprot#readStructBegin);" << endl;

  // Loop over reading in fields
  indent(out) <<
    "(try while true do" << endl;
  indent_up();
  indent_up();

  // Read beginning field marker
  indent(out) <<
    "let (_," << t <<","<<id<<") = iprot#readFieldBegin in" << endl;

  // Check for field STOP marker and break
  indent(out) <<
    "if " << t <<" = Protocol.T_STOP then" << endl;
  indent_up();
  indent(out) <<
      "raise Break" << endl;
    indent_down();
    indent(out) << "else ();" << endl;

    indent(out) << "(match " << id<<" with " << endl;
    indent_up();
    // Generate deserialization code for known cases
    for (f_iter = fields.begin(); f_iter != fields.end(); ++f_iter) {
      indent(out) << "| " << (*f_iter)->get_key() << " -> (";
      out << "if " << t <<" = " << type_to_enum((*f_iter)->get_type()) << " then" << endl;
      indent_up();
      indent_up();
      generate_deserialize_field(out, *f_iter,str);
      indent_down();
      out <<
        indent() << "else" << endl <<
        indent() << "  iprot#skip "<< t << ")" << endl;
      indent_down();
    }

    // In the default case we skip the field
    out <<
      indent() << "| _ -> " << "iprot#skip "<<t<<");" << endl;
    indent_down();
    // Read field end marker
    indent(out) << "iprot#readFieldEnd;" << endl;
    indent_down();
    indent(out) << "done; ()" << endl;
    indent_down();
    indent(out) << "with Break -> ());" << endl;

    indent(out) <<
      "iprot#readStructEnd;" << endl;

    indent(out) << str << endl << endl;
    indent_down();
    indent_down();
}

void t_ocaml_generator::generate_ocaml_struct_writer(ofstream& out,
                                               t_struct* tstruct) {
  string name = tstruct->get_name();
  const vector<t_field*>& fields = tstruct->get_sorted_members();
  vector<t_field*>::const_iterator f_iter;
  string str = tmp("_str");
  string f = tmp("_f");

  indent(out) <<
    "method write (oprot : Protocol.t) =" << endl;
  indent_up();
  indent(out) <<
    "oprot#writeStructBegin \""<<name<<"\";" << endl;

  for (f_iter = fields.begin(); f_iter != fields.end(); ++f_iter) {
    t_field *tmember = (*f_iter);
    string mname = "_"+decapitalize(tmember->get_name());
    string _v;

    if(struct_member_persistent(tmember)) {

      if(struct_member_omitable(tmember)
        && struct_member_default_cheaply_comparable(tmember)) {
        _v = "_v";
        // Avoid redundant encoding of members having default values.
        indent(out) << "(match " << mname << " with "
            << render_const_value(tmember->get_type(), tmember->get_value())
            << " -> () | " << _v << " -> " << endl;
      } else {
        _v = mname;
        indent(out) << "(" << endl;
      }

    } else {

      indent(out) << "(match " << mname << " with ";

      if(struct_member_omitable(tmember)) {
        out << "None -> ()";

        if(struct_member_default_cheaply_comparable(tmember)) {
          // Avoid redundant encoding of members having default values.
          out << " | Some "
              << render_const_value(tmember->get_type(), tmember->get_value())
              << " -> ()";
        }
        out << " | Some _v -> " << endl;
      } else {
        out << endl;
        indent(out) << "| None -> raise (Field_empty \""
                    << type_name(tstruct) << "." << mname << "\")" << endl;
        indent(out) << "| Some _v -> " << endl;
      }

      _v = "_v";
    }
    indent_up();
    // Write field header
    indent(out) << "oprot#writeFieldBegin(\""<< tmember->get_name()<<"\","
                << type_to_enum(tmember->get_type()) << ","
                << tmember->get_key()<<");" << endl;

    // Write field contents
    generate_serialize_field(out, tmember, _v);

    // Write field closer
    indent(out) << "oprot#writeFieldEnd" << endl;

    indent_down();
    indent(out) << ");" << endl;
  }

  // Write the struct map
  out <<
    indent() << "oprot#writeFieldStop;" << endl <<
    indent() << "oprot#writeStructEnd" << endl;

  indent_down();
}

/**
 * Generates a thrift service.
 *
 * @param tservice The service definition
 */
void t_ocaml_generator::generate_service(t_service* tservice) {
  string f_service_name = get_out_dir()+capitalize(service_name_)+".ml";
  f_service_.open(f_service_name.c_str());
  string f_service_i_name = get_out_dir()+capitalize(service_name_)+".mli";
  f_service_i_.open(f_service_i_name.c_str());

  f_service_ <<
    ocaml_autogen_comment() << endl <<
    ocaml_imports() << endl;
  f_service_i_ <<
    ocaml_autogen_comment() << endl <<
    ocaml_imports() << endl;

  /* if (tservice->get_extends() != NULL) {
    f_service_ <<
      "open " << capitalize(tservice->get_extends()->get_name()) << endl;
    f_service_i_ <<
      "open " << capitalize(tservice->get_extends()->get_name()) << endl;
  }
  */
  f_service_ <<
     "open " << capitalize(program_name_) << "_types" << endl <<
    endl;

  f_service_i_ <<
     "open " << capitalize(program_name_) << "_types" << endl <<
    endl;

  // Generate the three main parts of the service
  generate_service_helpers(tservice);
  generate_service_interface(tservice);
  generate_service_client(tservice);
  generate_service_server(tservice);


  // Close service file
  f_service_.close();
  f_service_i_.close();
}

/**
 * Generates helper functions for a service.
 *
 * @param tservice The service to generate a header definition for
 */
void t_ocaml_generator::generate_service_helpers(t_service* tservice) {
  vector<t_function*> functions = tservice->get_functions();
  vector<t_function*>::iterator f_iter;

  indent(f_service_) <<
    "(* HELPER FUNCTIONS AND STRUCTURES *)" << endl << endl;

  for (f_iter = functions.begin(); f_iter != functions.end(); ++f_iter) {
    t_struct* ts = (*f_iter)->get_arglist();
    generate_ocaml_struct_definition(f_service_, ts, false);
    generate_ocaml_function_helpers(*f_iter);
  }
}

/**
 * Generates a struct and helpers for a function.
 *
 * @param tfunction The function
 */
void t_ocaml_generator::generate_ocaml_function_helpers(t_function* tfunction) {
  t_struct result(program_, decapitalize(tfunction->get_name()) + "_result");
  t_field success(tfunction->get_returntype(), "success", 0);
  if (!tfunction->get_returntype()->is_void()) {
    result.append(&success);
  }

  t_struct* xs = tfunction->get_xceptions();
  const vector<t_field*>& fields = xs->get_members();
  vector<t_field*>::const_iterator f_iter;
  for (f_iter = fields.begin(); f_iter != fields.end(); ++f_iter) {
    result.append(*f_iter);
  }
  generate_ocaml_struct_definition(f_service_, &result, false);
}

/**
 * Generates a service interface definition.
 *
 * @param tservice The service to generate a header definition for
 */
void t_ocaml_generator::generate_service_interface(t_service* tservice) {
  f_service_ <<
    indent() << "class virtual iface =" << endl << "object (self)" << endl;
  f_service_i_ <<
    indent() << "class virtual iface :" << endl << "object" << endl;

  indent_up();

  if (tservice->get_extends() != NULL) {
    string extends = type_name(tservice->get_extends());
    indent(f_service_) << "inherit " << extends << ".iface" << endl;
    indent(f_service_i_) << "inherit " << extends << ".iface" << endl;
  }

  vector<t_function*> functions = tservice->get_functions();
  vector<t_function*>::iterator f_iter;
  for (f_iter = functions.begin(); f_iter != functions.end(); ++f_iter) {
    string ft = function_type(*f_iter,true,true);
    f_service_ <<
      indent() << "method virtual " << decapitalize((*f_iter)->get_name()) << " : " << ft  << endl;
    f_service_i_ <<
      indent() << "method virtual " << decapitalize((*f_iter)->get_name()) << " : " << ft << endl;
  }
  indent_down();
  indent(f_service_) << "end" << endl << endl;
  indent(f_service_i_) << "end" << endl << endl;
}

/**
 * Generates a service client definition. Note that in OCaml, the client doesn't implement iface. This is because
 * The client does not (and should not have to) deal with arguments being None.
 *
 * @param tservice The service to generate a server for.
 */
void t_ocaml_generator::generate_service_client(t_service* tservice) {
  string extends = "";
  indent(f_service_) <<
    "class client (iprot : Protocol.t) (oprot : Protocol.t) =" << endl << "object (self)" << endl;
  indent(f_service_i_) <<
    "class client : Protocol.t -> Protocol.t -> " << endl << "object" << endl;
  indent_up();


  if (tservice->get_extends() != NULL) {
    extends = type_name(tservice->get_extends());
    indent(f_service_) << "inherit " << extends << ".client iprot oprot as super" << endl;
    indent(f_service_i_) << "inherit " << extends << ".client" << endl;
  }
  indent(f_service_) << "val mutable seqid = 0" << endl;


  // Generate client method implementations
  vector<t_function*> functions = tservice->get_functions();
  vector<t_function*>::const_iterator f_iter;
  for (f_iter = functions.begin(); f_iter != functions.end(); ++f_iter) {
    t_struct* arg_struct = (*f_iter)->get_arglist();
    const vector<t_field*>& fields = arg_struct->get_members();
    vector<t_field*>::const_iterator fld_iter;
    string funname = (*f_iter)->get_name();

    // Open function
    indent(f_service_) <<
      "method " << function_signature(*f_iter) << " = " << endl;
    indent(f_service_i_) <<
      "method " << decapitalize((*f_iter)->get_name()) << " : " << function_type(*f_iter,true,false) << endl;
    indent_up();
    indent(f_service_) <<
      "self#send_" << funname;


    for (fld_iter = fields.begin(); fld_iter != fields.end(); ++fld_iter) {
      f_service_ << " " << decapitalize((*fld_iter)->get_name());
    }
    f_service_ << ";" << endl;

    if (!(*f_iter)->is_oneway()) {
      f_service_ << indent();
      f_service_ <<
        "self#recv_" << funname << endl;
    }
    indent_down();

    indent(f_service_) <<
      "method private send_" << function_signature(*f_iter) << " = " << endl;
    indent_up();

    std::string argsname = decapitalize((*f_iter)->get_name() + "_args");

    // Serialize the request header
    f_service_ <<
      indent() << "oprot#writeMessageBegin (\"" << (*f_iter)->get_name() << "\", Protocol.CALL, seqid);" << endl;

    f_service_ <<
      indent() << "let args = new " << argsname << " in" << endl;
    indent_up();

    for (fld_iter = fields.begin(); fld_iter != fields.end(); ++fld_iter) {
      f_service_ <<
        indent() << "args#set_" << (*fld_iter)->get_name() << " " << (*fld_iter)->get_name() << ";" << endl;
    }

    // Write to the stream
    f_service_ <<
      indent() << "args#write oprot;" << endl <<
      indent() << "oprot#writeMessageEnd;" << endl <<
      indent() << "oprot#getTransport#flush" << endl;

    indent_down();
    indent_down();

    if (!(*f_iter)->is_oneway()) {
      std::string resultname = decapitalize((*f_iter)->get_name() + "_result");
      t_struct noargs(program_);

      t_function recv_function((*f_iter)->get_returntype(),
                               string("recv_") + (*f_iter)->get_name(),
                               &noargs);
      // Open function
      f_service_ <<
        indent() << "method private " << function_signature(&recv_function) << " =" << endl;
      indent_up();

      // TODO(mcslee): Validate message reply here, seq ids etc.

      f_service_ <<
        indent() << "let (fname, mtype, rseqid) = iprot#readMessageBegin in" << endl;
      indent_up();
      f_service_ <<
        indent() << "(if mtype = Protocol.EXCEPTION then" << endl <<
        indent() << "  let x = Application_Exn.read iprot in" << endl;
      indent_up();
      f_service_ <<
        indent() << "  (iprot#readMessageEnd;" <<
        indent() << "   raise (Application_Exn.E x))" << endl;
      indent_down();
      f_service_ <<
        indent() << "else ());" << endl;
      string res = "_";

      t_struct* xs = (*f_iter)->get_xceptions();
      const std::vector<t_field*>& xceptions = xs->get_members();

      if (!(*f_iter)->get_returntype()->is_void() || xceptions.size() > 0) {
        res = "result";
      }
      f_service_ <<
        indent() << "let "<<res<<" = read_" << resultname << " iprot in" << endl;
      indent_up();
      f_service_ <<
        indent() << "iprot#readMessageEnd;" << endl;

      // Careful, only return _result if not a void function
      if (!(*f_iter)->get_returntype()->is_void()) {
        f_service_ <<
          indent() << "match result#get_success with Some v -> v | None -> (" << endl;
        indent_up();
      }


      vector<t_field*>::const_iterator x_iter;
      for (x_iter = xceptions.begin(); x_iter != xceptions.end(); ++x_iter) {
        f_service_ <<
          indent() << "(match result#get_" << (*x_iter)->get_name() << " with None -> () | Some _v ->" << endl;
        indent(f_service_) << "  raise (" << capitalize(type_name((*x_iter)->get_type())) << " _v));" << endl;
      }

      // Careful, only return _result if not a void function
      if ((*f_iter)->get_returntype()->is_void()) {
        indent(f_service_) <<
          "()" << endl;
      } else {
        f_service_ <<
          indent() << "raise (Application_Exn.E (Application_Exn.create Application_Exn.MISSING_RESULT \"" << (*f_iter)->get_name() << " failed: unknown result\")))" << endl;
        indent_down();
      }

      // Close function
      indent_down();
      indent_down();
      indent_down();
    }
  }

  indent_down();
  indent(f_service_) << "end" << endl << endl;
  indent(f_service_i_) << "end" << endl << endl;
}

/**
 * Generates a service server definition.
 *
 * @param tservice The service to generate a server for.
 */
void t_ocaml_generator::generate_service_server(t_service* tservice) {
  // Generate the dispatch methods
  vector<t_function*> functions = tservice->get_functions();
  vector<t_function*>::iterator f_iter;


  // Generate the header portion
  indent(f_service_) <<
    "class processor (handler : iface) =" << endl << indent() << "object (self)" << endl;
  indent(f_service_i_) <<
    "class processor : iface ->" << endl << indent() << "object" << endl;
  indent_up();

  f_service_ <<
     indent() << "inherit Processor.t" << endl <<
    endl;
  f_service_i_ <<
     indent() << "inherit Processor.t" << endl <<
    endl;
  string extends = "";

  if (tservice->get_extends() != NULL) {
    extends = type_name(tservice->get_extends());
    indent(f_service_) << "inherit " + extends + ".processor (handler :> " + extends + ".iface)" << endl;
    indent(f_service_i_) << "inherit " + extends + ".processor" << endl;
  }

  if (extends.empty()) {
    indent(f_service_) << "val processMap = Hashtbl.create " << functions.size() << endl;
  }
  indent(f_service_i_) << "val processMap : (string, int * Protocol.t * Protocol.t -> unit) Hashtbl.t" << endl;

  // Generate the server implementation
  indent(f_service_) <<
    "method process iprot oprot =" << endl;
  indent(f_service_i_) <<
    "method process : Protocol.t -> Protocol.t -> bool" << endl;
  indent_up();

  f_service_ <<
    indent() << "let (name, typ, seqid)  = iprot#readMessageBegin in" << endl;
  indent_up();
  // TODO(mcslee): validate message

  // HOT: dictionary function lookup
  f_service_ <<
    indent() << "if Hashtbl.mem processMap name then" << endl <<
    indent() << "  (Hashtbl.find processMap name) (seqid, iprot, oprot)" << endl <<
    indent() << "else (" << endl <<
    indent() << "  iprot#skip(Protocol.T_STRUCT);" << endl <<
    indent() << "  iprot#readMessageEnd;" << endl <<
    indent() << "  let x = Application_Exn.create Application_Exn.UNKNOWN_METHOD (\"Unknown function \"^name) in" << endl <<
    indent() << "    oprot#writeMessageBegin(name, Protocol.EXCEPTION, seqid);" << endl <<
    indent() << "    x#write oprot;" << endl <<
    indent() << "    oprot#writeMessageEnd;" << endl <<
    indent() << "    oprot#getTransport#flush" << endl <<
    indent() << ");" << endl;

  // Read end of args field, the T_STOP, and the struct close
  f_service_ <<
    indent() << "true" << endl;
  indent_down();
  indent_down();
  // Generate the process subfunctions
  for (f_iter = functions.begin(); f_iter != functions.end(); ++f_iter) {
    generate_process_function(tservice, *f_iter);
  }

  indent(f_service_) << "initializer" << endl;
  indent_up();
  for (f_iter = functions.begin(); f_iter != functions.end(); ++f_iter) {
    f_service_ <<
      indent() << "Hashtbl.add processMap \"" << (*f_iter)->get_name() << "\" self#process_" << (*f_iter)->get_name() << ";" << endl;
  }
  indent_down();

  indent_down();
  indent(f_service_) << "end" << endl << endl;
  indent(f_service_i_) << "end" << endl << endl;
}

/**
 * Generates a process function definition.
 *
 * @param tfunction The function to write a dispatcher for
 */
void t_ocaml_generator::generate_process_function(t_service* tservice,
                                               t_function* tfunction) {
  (void) tservice;
  // Open function
  indent(f_service_) <<
    "method private process_" << tfunction->get_name() <<
    " (seqid, iprot, oprot) =" << endl;
  indent_up();

  string argsname = decapitalize(tfunction->get_name()) + "_args";
  string resultname = decapitalize(tfunction->get_name()) + "_result";

  // Generate the function call
  t_struct* arg_struct = tfunction->get_arglist();
  const std::vector<t_field*>& fields = arg_struct->get_members();
  vector<t_field*>::const_iterator f_iter;

  string args = "args";
  if(fields.size() == 0){
    args="_";
  }

  f_service_ <<
    indent() << "let "<<args<<" = read_" << argsname << " iprot in" << endl;
  indent_up();
  f_service_ <<
    indent() << "iprot#readMessageEnd;" << endl;

  t_struct* xs = tfunction->get_xceptions();
  const std::vector<t_field*>& xceptions = xs->get_members();
  vector<t_field*>::const_iterator x_iter;

  // Declare result for non oneway function
  if (!tfunction->is_oneway()) {
    f_service_ <<
      indent() << "let result = new " << resultname << " in" << endl;
    indent_up();
  }

  // Try block for a function with exceptions
  if (xceptions.size() > 0) {
    f_service_ <<
      indent() << "(try" << endl;
    indent_up();
  }




  f_service_ << indent();
  if (!tfunction->is_oneway() && !tfunction->get_returntype()->is_void()) {
    f_service_ << "result#set_success ";
  }
  f_service_ <<
    "(handler#" << tfunction->get_name();
  for (f_iter = fields.begin(); f_iter != fields.end(); ++f_iter) {
    f_service_ <<  " args#get_" << (*f_iter)->get_name();
  }
  f_service_ << ");" << endl;


  if (xceptions.size() > 0) {
    indent_down();
    indent(f_service_) << "with" <<endl;
    indent_up();
    for (x_iter = xceptions.begin(); x_iter != xceptions.end(); ++x_iter) {
      f_service_ <<
        indent() << "| " << capitalize(type_name((*x_iter)->get_type())) << " " << (*x_iter)->get_name() << " -> " << endl;
      indent_up();
      indent_up();
      if(!tfunction->is_oneway()){
           f_service_ <<
             indent() << "result#set_" << (*x_iter)->get_name() << " " << (*x_iter)->get_name() << endl;
      } else {
        indent(f_service_) << "()";
      }
      indent_down();
      indent_down();
    }
    indent_down();
    f_service_ << indent() << ");" << endl;
  }



  // Shortcut out here for oneway functions
  if (tfunction->is_oneway()) {
    f_service_ <<
      indent() << "()" << endl;
    indent_down();
    indent_down();
    return;
  }

  f_service_ <<
    indent() << "oprot#writeMessageBegin (\"" << tfunction->get_name() << "\", Protocol.REPLY, seqid);" << endl <<
    indent() << "result#write oprot;" << endl <<
    indent() << "oprot#writeMessageEnd;" << endl <<
    indent() << "oprot#getTransport#flush" << endl;

  // Close function
  indent_down();
  indent_down();
  indent_down();
}

/**
 * Deserializes a field of any type.
 */
void t_ocaml_generator::generate_deserialize_field(ofstream &out,
                                                   t_field* tfield,
                                                   string prefix){
  t_type* type = tfield->get_type();


  string name = decapitalize(tfield->get_name());
  indent(out) << prefix << "#set_"<<name << " ";
  generate_deserialize_type(out,type);
  out << endl;
}


/**
 * Deserializes a field of any type.
 */
void t_ocaml_generator::generate_deserialize_type(ofstream &out,
                                                   t_type* type){
  type = get_true_type(type);

  if (type->is_void()) {
    throw "CANNOT GENERATE DESERIALIZE CODE FOR void TYPE";
  }


  if (type->is_struct() || type->is_xception()) {
    generate_deserialize_struct(out,
                                (t_struct*)type);
  } else if (type->is_container()) {
    generate_deserialize_container(out, type);
  } else if (type->is_base_type()) {
    out << "iprot#";
    t_base_type::t_base tbase = ((t_base_type*)type)->get_base();
    switch (tbase) {
    case t_base_type::TYPE_VOID:
      throw "compiler error: cannot serialize void field in a struct";
      break;
    case t_base_type::TYPE_STRING:
      out << "readString";
      break;
    case t_base_type::TYPE_BOOL:
      out << "readBool";
      break;
    case t_base_type::TYPE_BYTE:
      out << "readByte";
      break;
    case t_base_type::TYPE_I16:
      out << "readI16";
      break;
    case t_base_type::TYPE_I32:
      out << "readI32";
      break;
    case t_base_type::TYPE_I64:
      out << "readI64";
      break;
    case t_base_type::TYPE_DOUBLE:
      out << "readDouble";
      break;
    default:
      throw "compiler error: no PHP name for base type " + t_base_type::t_base_name(tbase);
    }
  } else if (type->is_enum()) {
    string ename = capitalize(type->get_name());
    out << "(" <<ename << ".of_i iprot#readI32)";
  } else {
    printf("DO NOT KNOW HOW TO DESERIALIZE TYPE '%s'\n",
           type->get_name().c_str());
  }
}


/**
 * Generates an unserializer for a struct, calling read()
 */
void t_ocaml_generator::generate_deserialize_struct(ofstream &out,
                                                  t_struct* tstruct) {
  string prefix = "";
  t_program* program = tstruct->get_program();
  if (program != NULL && program != program_) {
     prefix = capitalize(program->get_name()) + "_types.";
  }
  string name = decapitalize(tstruct->get_name());
  out << "(" << prefix << "read_" << name << " iprot)";

}

/**
 * Serialize a container by writing out the header followed by
 * data and then a footer.
 */
void t_ocaml_generator::generate_deserialize_container(ofstream &out,
                                                    t_type* ttype) {
  string size = tmp("_size");
  string ktype = tmp("_ktype");
  string vtype = tmp("_vtype");
  string etype = tmp("_etype");
  string con = tmp("_con");

  t_field fsize(g_type_i32, size);
  t_field fktype(g_type_byte, ktype);
  t_field fvtype(g_type_byte, vtype);
  t_field fetype(g_type_byte, etype);

  out << endl;
  indent_up();
  // Declare variables, read header
  if (ttype->is_map()) {
    indent(out) << "(let ("<<ktype<<","<<vtype<<","<<size<<") = iprot#readMapBegin in" << endl;
    indent(out) << "let "<<con<<" = Hashtbl.create "<<size<<" in" << endl;
    indent_up();
    indent(out) << "for i = 1 to "<<size<<" do" <<endl;
    indent_up();
    indent(out) << "let _k = ";
    generate_deserialize_type(out,((t_map*)ttype)->get_key_type());
    out << " in" << endl;
    indent(out) << "let _v = ";
    generate_deserialize_type(out,((t_map*)ttype)->get_val_type());
    out << " in" << endl;
    indent_up();
    indent(out) << "Hashtbl.add "<<con<< " _k _v" << endl;
    indent_down();
    indent_down();
    indent(out) << "done; iprot#readMapEnd; "<<con<<")";
    indent_down();
  } else if (ttype->is_set()) {
    indent(out) << "(let ("<<etype<<","<<size<<") = iprot#readSetBegin in" << endl;
    indent(out) << "let "<<con<<" = Hashtbl.create "<<size<<" in" << endl;
    indent_up();
    indent(out) << "for i = 1 to "<<size<<" do" <<endl;
    indent_up();
    indent(out) << "Hashtbl.add "<<con<<" ";
    generate_deserialize_type(out,((t_set*)ttype)->get_elem_type());
    out << " true" << endl;
    indent_down();
    indent(out) << "done; iprot#readSetEnd; "<<con<<")";
    indent_down();
  } else if (ttype->is_list()) {
    indent(out) << "(let ("<<etype<<","<<size<<") = iprot#readListBegin in" << endl;
    indent_up();
    indent(out) << "let "<<con<<" = (Array.to_list (Array.init "<<size<<" (fun _ -> ";
    generate_deserialize_type(out,((t_list*)ttype)->get_elem_type());
    out << "))) in" << endl;
    indent_up();
    indent(out) << "iprot#readListEnd; "<<con<<")";
    indent_down();
    indent_down();
  }
  indent_down();
}



/**
 * Serializes a field of any type.
 *
 * @param tfield The field to serialize
 * @param prefix Name to prepend to field name
 */
void t_ocaml_generator::generate_serialize_field(ofstream &out,
                                                 t_field* tfield,
                                                 string name) {
  t_type* type = get_true_type(tfield->get_type());

  // Do nothing for void types
  if (type->is_void()) {
    throw "CANNOT GENERATE SERIALIZE CODE FOR void TYPE: " +
      tfield->get_name();
  }

  if(name.length() == 0){
    name = decapitalize(tfield->get_name());
  }

  if (type->is_struct() || type->is_xception()) {
    generate_serialize_struct(out,
                              (t_struct*)type,
                              name);
  } else if (type->is_container()) {
    generate_serialize_container(out,
                                 type,
                                 name);
  } else if (type->is_base_type() || type->is_enum()) {


    indent(out) <<
      "oprot#";

    if (type->is_base_type()) {
      t_base_type::t_base tbase = ((t_base_type*)type)->get_base();
      switch (tbase) {
      case t_base_type::TYPE_VOID:
        throw
          "compiler error: cannot serialize void field in a struct: " + name;
        break;
      case t_base_type::TYPE_STRING:
        out << "writeString(" << name << ")";
        break;
      case t_base_type::TYPE_BOOL:
        out << "writeBool(" << name << ")";
       break;
      case t_base_type::TYPE_BYTE:
        out << "writeByte(" << name << ")";
        break;
      case t_base_type::TYPE_I16:
        out << "writeI16(" << name << ")";
        break;
      case t_base_type::TYPE_I32:
        out << "writeI32(" << name << ")";
        break;
      case t_base_type::TYPE_I64:
        out << "writeI64(" << name << ")";
        break;
      case t_base_type::TYPE_DOUBLE:
        out << "writeDouble(" << name << ")";
        break;
      default:
        throw "compiler error: no ocaml name for base type " + t_base_type::t_base_name(tbase);
      }
    } else if (type->is_enum()) {
      string ename = capitalize(type->get_name());
      out << "writeI32("<<ename<<".to_i " << name << ")";
    }

  } else {
    printf("DO NOT KNOW HOW TO SERIALIZE FIELD '%s' TYPE '%s'\n",
           tfield->get_name().c_str(),
           type->get_name().c_str());
  }
  out << ";" << endl;
}

/**
 * Serializes all the members of a struct.
 *
 * @param tstruct The struct to serialize
 * @param prefix  String prefix to attach to all fields
 */
void t_ocaml_generator::generate_serialize_struct(ofstream &out,
                                               t_struct* tstruct,
                                               string prefix) {
  (void) tstruct;
  indent(out) << prefix << "#write(oprot)";
}

void t_ocaml_generator::generate_serialize_container(ofstream &out,
                                                  t_type* ttype,
                                                  string prefix) {
  if (ttype->is_map()) {
    indent(out) << "oprot#writeMapBegin("<< type_to_enum(((t_map*)ttype)->get_key_type()) << ",";
    out << type_to_enum(((t_map*)ttype)->get_val_type()) << ",";
    out << "Hashtbl.length " << prefix << ");" << endl;
  } else if (ttype->is_set()) {
    indent(out) <<
      "oprot#writeSetBegin(" << type_to_enum(((t_set*)ttype)->get_elem_type()) << ",";
    out << "Hashtbl.length " << prefix << ");" << endl;
  } else if (ttype->is_list()) {
    indent(out) <<
      "oprot#writeListBegin(" << type_to_enum(((t_list*)ttype)->get_elem_type()) << ",";
    out << "List.length " << prefix << ");" << endl;
  }

  if (ttype->is_map()) {
    string kiter = tmp("_kiter");
    string viter = tmp("_viter");
    indent(out) << "Hashtbl.iter (fun "<<kiter<<" -> fun " << viter << " -> " << endl;
    indent_up();
    generate_serialize_map_element(out, (t_map*)ttype, kiter, viter);
    indent_down();
    indent(out) << ") " << prefix << ";" << endl;
  } else if (ttype->is_set()) {
    string iter = tmp("_iter");
    indent(out) << "Hashtbl.iter (fun "<<iter<<" -> fun _ -> ";
    indent_up();
    generate_serialize_set_element(out, (t_set*)ttype, iter);
    indent_down();
    indent(out) << ") " << prefix << ";" << endl;
  } else if (ttype->is_list()) {
    string iter = tmp("_iter");
    indent(out) << "List.iter (fun "<<iter<<" -> ";
    indent_up();
    generate_serialize_list_element(out, (t_list*)ttype, iter);
    indent_down();
    indent(out) << ") " << prefix << ";" <<  endl;
  }

  if (ttype->is_map()) {
    indent(out) <<
      "oprot#writeMapEnd";
  } else if (ttype->is_set()) {
    indent(out) <<
      "oprot#writeSetEnd";
  } else if (ttype->is_list()) {
    indent(out) <<
      "oprot#writeListEnd";
  }
}

/**
 * Serializes the members of a map.
 *
 */
void t_ocaml_generator::generate_serialize_map_element(ofstream &out,
                                                     t_map* tmap,
                                                     string kiter,
                                                     string viter) {
  t_field kfield(tmap->get_key_type(), kiter);
  generate_serialize_field(out, &kfield);

  t_field vfield(tmap->get_val_type(), viter);
  generate_serialize_field(out, &vfield);
}

/**
 * Serializes the members of a set.
 */
void t_ocaml_generator::generate_serialize_set_element(ofstream &out,
                                                     t_set* tset,
                                                     string iter) {
  t_field efield(tset->get_elem_type(), iter);
  generate_serialize_field(out, &efield);
}

/**
 * Serializes the members of a list.
 */
void t_ocaml_generator::generate_serialize_list_element(ofstream &out,
                                                      t_list* tlist,
                                                      string iter) {
  t_field efield(tlist->get_elem_type(), iter);
  generate_serialize_field(out, &efield);
}



/**
 * Renders a function signature of the form 'name args'
 *
 * @param tfunction Function definition
 * @return String of rendered function definition
 */
string t_ocaml_generator::function_signature(t_function* tfunction,
                                           string prefix) {
  return
    prefix + decapitalize(tfunction->get_name()) +
    " " +  argument_list(tfunction->get_arglist());
}

string t_ocaml_generator::function_type(t_function* tfunc, bool method, bool options){
  string result="";

  const vector<t_field*>& fields = tfunc->get_arglist()->get_members();
  vector<t_field*>::const_iterator f_iter;
  for (f_iter = fields.begin(); f_iter != fields.end(); ++f_iter) {
    result += render_ocaml_type((*f_iter)->get_type());
    if(options)
      result += " option";
    result += " -> ";
  }
  if(fields.empty() && !method){
    result += "unit -> ";
  }
  result += render_ocaml_type(tfunc->get_returntype());
  return result;
}

/**
 * Renders a field list
 */
string t_ocaml_generator::argument_list(t_struct* tstruct) {
  string result = "";

  const vector<t_field*>& fields = tstruct->get_members();
  vector<t_field*>::const_iterator f_iter;
  bool first = true;
  for (f_iter = fields.begin(); f_iter != fields.end(); ++f_iter) {
    if (first) {
      first = false;
    } else {
      result += " ";
    }
    result += (*f_iter)->get_name();
  }
  return result;
}

string t_ocaml_generator::type_name(t_type* ttype) {
  string prefix = "";
  t_program* program = ttype->get_program();
  if (program != NULL && program != program_) {
    if (!ttype->is_service()) {
      prefix = capitalize(program->get_name()) + "_types.";
    }
  }

  string name = ttype->get_name();
  if(ttype->is_service()){
    name = capitalize(name);
  } else {
    name = decapitalize(name);
  }
  return prefix + name;
}

/**
 * Converts the parse type to a Protocol.t_type enum
 */
string t_ocaml_generator::type_to_enum(t_type* type) {
  type = get_true_type(type);

  if (type->is_base_type()) {
    t_base_type::t_base tbase = ((t_base_type*)type)->get_base();
    switch (tbase) {
    case t_base_type::TYPE_VOID:
      return "Protocol.T_VOID";
    case t_base_type::TYPE_STRING:
      return "Protocol.T_STRING";
    case t_base_type::TYPE_BOOL:
      return "Protocol.T_BOOL";
    case t_base_type::TYPE_BYTE:
      return "Protocol.T_BYTE";
    case t_base_type::TYPE_I16:
      return "Protocol.T_I16";
    case t_base_type::TYPE_I32:
      return "Protocol.T_I32";
    case t_base_type::TYPE_I64:
      return "Protocol.T_I64";
    case t_base_type::TYPE_DOUBLE:
      return "Protocol.T_DOUBLE";
    }
  } else if (type->is_enum()) {
    return "Protocol.T_I32";
  } else if (type->is_struct() || type->is_xception()) {
    return "Protocol.T_STRUCT";
  } else if (type->is_map()) {
    return "Protocol.T_MAP";
  } else if (type->is_set()) {
    return "Protocol.T_SET";
  } else if (type->is_list()) {
    return "Protocol.T_LIST";
  }

  throw "INVALID TYPE IN type_to_enum: " + type->get_name();
}

/**
 * Converts the parse type to an ocaml type
 */
string t_ocaml_generator::render_ocaml_type(t_type* type) {
  type = get_true_type(type);

  if (type->is_base_type()) {
    t_base_type::t_base tbase = ((t_base_type*)type)->get_base();
    switch (tbase) {
    case t_base_type::TYPE_VOID:
      return "unit";
    case t_base_type::TYPE_STRING:
      return "string";
    case t_base_type::TYPE_BOOL:
      return "bool";
    case t_base_type::TYPE_BYTE:
      return "int";
    case t_base_type::TYPE_I16:
      return "int";
    case t_base_type::TYPE_I32:
      return "Int32.t";
    case t_base_type::TYPE_I64:
      return "Int64.t";
    case t_base_type::TYPE_DOUBLE:
      return "float";
    }
  } else if (type->is_enum()) {
    return capitalize(((t_enum*)type)->get_name())+".t";
  } else if (type->is_struct() || type->is_xception()) {
    return type_name((t_struct*)type);
  } else if (type->is_map()) {
    t_type* ktype = ((t_map*)type)->get_key_type();
    t_type* vtype = ((t_map*)type)->get_val_type();
    return "("+render_ocaml_type(ktype)+","+render_ocaml_type(vtype)+") Hashtbl.t";
  } else if (type->is_set()) {
    t_type* etype = ((t_set*)type)->get_elem_type();
    return "("+render_ocaml_type(etype)+",bool) Hashtbl.t";
  } else if (type->is_list()) {
    t_type* etype = ((t_list*)type)->get_elem_type();
    return render_ocaml_type(etype)+" list";
  }

  throw "INVALID TYPE IN type_to_enum: " + type->get_name();
}


THRIFT_REGISTER_GENERATOR(ocaml, "OCaml", "")