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/*

 * 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"

using namespace std;

/**

 * Haskell code generator.

 *

 */

class t_hs_generator : public t_oop_generator {

 public:

  t_hs_generator(

      t_program* program,

      const std::map<std::string, std::string>& parsed_options,

      const std::string& option_string)

    : t_oop_generator(program)

  {

    out_dir_base_ = "gen-hs";

  }

  /**

   * Init and close methods

   */

  void init_generator();

  void close_generator();

  /**

   * Program-level generation functions

   */

  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);

  /**

   * Struct generation code

   */

  void generate_hs_struct(t_struct* tstruct, bool is_exception);

  void generate_hs_struct_definition(std::ofstream &out,t_struct* tstruct, bool is_xception=false,bool helper=false);

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

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

  void generate_hs_function_helpers(t_function* tfunction);

  /**

   * 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 hs_autogen_comment();

  std::string hs_imports();

  std::string type_name(t_type* ttype);

  std::string function_type(t_function* tfunc, bool options = false, bool io = false, bool method = false);

  std::string type_to_enum(t_type* ttype);

  std::string render_hs_type(t_type* type, bool needs_parens = true);

 private:

  /**

   * File streams

   */

  std::ofstream f_types_;

  std::ofstream f_consts_;

  std::ofstream f_service_;

  std::ofstream f_iface_;

  std::ofstream f_client_;

};

/**

 * Prepares for file generation by opening up the necessary file output

 * streams.

 *

 * @param tprogram The program to generate

 */

void t_hs_generator::init_generator() {

  // Make output directory

  MKDIR(get_out_dir().c_str());

  // Make output file

  string pname = capitalize(program_name_);

  string f_types_name = get_out_dir()+pname+"_Types.hs";

  f_types_.open(f_types_name.c_str());

  string f_consts_name = get_out_dir()+pname+"_Consts.hs";

  f_consts_.open(f_consts_name.c_str());

  // Print header

  f_types_ <<

    hs_autogen_comment() << endl <<

    "module " << pname <<"_Types where" << endl <<

    hs_imports() << endl;

  f_consts_ <<

    hs_autogen_comment() << endl <<

    "module " << pname <<"_Consts where" << endl <<

    hs_imports() << endl <<

    "import " << pname<<"_Types"<< endl;

}

/**

 * Autogen'd comment

 */

string t_hs_generator::hs_autogen_comment() {

  return

    std::string("-----------------------------------------------------------------\n") +

    "-- Autogenerated by Thrift                                     --\n" +

    "--                                                             --\n" +

    "-- DO NOT EDIT UNLESS YOU ARE SURE YOU KNOW WHAT YOU ARE DOING --\n" +

    "-----------------------------------------------------------------\n";

}

/**

 * Prints standard thrift imports

 */

string t_hs_generator::hs_imports() {

  return "import Thrift\nimport Data.Typeable ( Typeable )\nimport Control.Exception\nimport qualified Data.Map as Map\nimport qualified Data.Set as Set\nimport Data.Int";

}

/**

 * Closes the type files

 */

void t_hs_generator::close_generator() {

  // Close types file

  f_types_.close();

  f_consts_.close();

}

/**

 * Generates a typedef. Ez.

 *

 * @param ttypedef The type definition

 */

void t_hs_generator::generate_typedef(t_typedef* ttypedef) {

  f_types_ <<

    indent() << "type "<< capitalize(ttypedef->get_symbolic()) << " = " << render_hs_type(ttypedef->get_type(), false) << endl << endl;

}

/**

 * Generates code for an enumerated type.

 * the values.

 *

 * @param tenum The enumeration

 */

void t_hs_generator::generate_enum(t_enum* tenum) {

  indent(f_types_) << "data "<<capitalize(tenum->get_name())<<" = ";

  indent_up();

  vector<t_enum_value*> constants = tenum->get_constants();

  vector<t_enum_value*>::iterator c_iter;

  bool first = true;

  for (c_iter = constants.begin(); c_iter != constants.end(); ++c_iter) {

    string name = capitalize((*c_iter)->get_name());

    if(first)

      first=false;

    else

      f_types_ << "|";

    f_types_ << name;

  }

  indent(f_types_) << "deriving (Show,Eq, Typeable, Ord)" << endl;

  indent_down();

  int value = -1;

  indent(f_types_) << "instance Enum " << capitalize(tenum->get_name()) << " where" << endl;

  indent_up();

  indent(f_types_) << "fromEnum t = case t of" << endl;

  indent_up();

  for (c_iter = constants.begin(); c_iter != constants.end(); ++c_iter) {

    if ((*c_iter)->has_value()) {

      value = (*c_iter)->get_value();

    } else {

      ++value;

    }

    string name = capitalize((*c_iter)->get_name());

    f_types_ <<

      indent() << name << " -> " << value << endl;

  }

  indent_down();

  indent(f_types_) << "toEnum t = case t of" << endl;

  indent_up();

  for(c_iter = constants.begin(); c_iter != constants.end(); ++c_iter) {

    if ((*c_iter)->has_value()) {

      value = (*c_iter)->get_value();

    } else {

      ++value;

    }

    string name = capitalize((*c_iter)->get_name());

    f_types_ <<

      indent() << value << " -> " << name << endl;

  }

  indent(f_types_) << "_ -> throw ThriftException" << endl;

  indent_down();

  indent_down();

}

/**

 * Generate a constant value

 */

void t_hs_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_) << name << " :: " << render_hs_type(type, false) << endl;

  indent(f_consts_) << 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_hs_generator::render_const_value(t_type* type, t_const_value* value) {

  type = get_true_type(type);

  std::ostringstream out;

  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:

    case t_base_type::TYPE_I32:

    case t_base_type::TYPE_I64:

      out << value->get_integer();

      break;

    case t_base_type::TYPE_DOUBLE:

      if (value->get_type() == t_const_value::CV_INTEGER) {

        out << value->get_integer();

      } 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;

    int val = -1;

    for (c_iter = constants.begin(); c_iter != constants.end(); ++c_iter) {

      if ((*c_iter)->has_value()) {

        val = (*c_iter)->get_value();

      } else {

        ++val;

      }

      if(val == value->get_integer()){

        indent(out) << capitalize((*c_iter)->get_name());

        break;

      }

    }

  } else if (type->is_struct() || type->is_xception()) {

    string cname = type_name(type);

    indent(out) << cname << "{";

    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;

    bool first = true;

    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();

      if(first)

        first=false;

      else

        out << ",";

      out << "f_" << cname << "_" << fname << " = Just (" << render_const_value(field_type, v_iter->second) << ")";

    }

    indent(out) << "}";

  } 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;

    out << "(Map.fromList [";

    bool first=true;

    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);

      if(first)

        first=false;

      else

        out << ",";

      out << "(" << key << ","<< val << ")";

    }

    out << "])";

  } else if (type->is_list() || type->is_set()) {

    t_type* etype;

    if (type->is_list()) {

        etype = ((t_list*) type)->get_elem_type();

    } else  {

        etype = ((t_set*) type)->get_elem_type();

    }

    const vector<t_const_value*>& val = value->get_list();

    vector<t_const_value*>::const_iterator v_iter;

    bool first = true;

    if (type->is_set())

        out << "(Set.fromList ";

    out << "[";

    for (v_iter = val.begin(); v_iter != val.end(); ++v_iter) {

      if(first)

        first=false;

      else

        out << ",";

      out << render_const_value(etype, *v_iter);

    }

    out << "]";

    if (type->is_set())

        out << ")";

  } else {

    throw "CANNOT GENERATE CONSTANT FOR TYPE: " + type->get_name();

  }

  return out.str();

}

/**

 * Generates a "struct"

 */

void t_hs_generator::generate_struct(t_struct* tstruct) {

  generate_hs_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_hs_generator::generate_xception(t_struct* txception) {

  generate_hs_struct(txception, true);

}

/**

 * Generates a Haskell struct

 */

void t_hs_generator::generate_hs_struct(t_struct* tstruct,

                                              bool is_exception) {

  generate_hs_struct_definition(f_types_,tstruct, is_exception,false);

}

/**

 * Generates a struct definition for a thrift data type.

 *

 * @param tstruct The struct definition

 */

void t_hs_generator::generate_hs_struct_definition(ofstream& out,

                                                   t_struct* tstruct,

                                                   bool is_exception,

                                                   bool helper) {

  string tname = type_name(tstruct);

  string name = tstruct->get_name();

  const vector<t_field*>& members = tstruct->get_members();

  vector<t_field*>::const_iterator m_iter;

  indent(out) << "data "<<tname<<" = "<<tname;

  if (members.size() > 0) {

    out << "{";

    bool first=true;

    for (m_iter = members.begin(); m_iter != members.end(); ++m_iter) {

      if(first)

        first=false;

      else

        out << ",";

      string mname = (*m_iter)->get_name();

      out << "f_" << tname << "_" << mname << " :: Maybe " << render_hs_type((*m_iter)->get_type());

    }

    out << "}";

  }

  out << " deriving (Show,Eq,Ord,Typeable)" << endl;

  if (is_exception) out << "instance Exception " << tname << endl;

  generate_hs_struct_writer(out, tstruct);

  generate_hs_struct_reader(out, tstruct);

  //f_struct_.close();

}

/**

 * Generates the read method for a struct

 */

void t_hs_generator::generate_hs_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) << "read_" << sname << "_fields iprot rec = do" << endl;

  indent_up(); // do

  // Read beginning field marker

  indent(out) << "(_," << t <<","<<id<<") <- readFieldBegin iprot" << endl;

  // Check for field STOP marker and break

  indent(out) <<

    "if " << t <<" == T_STOP then return rec else" << endl;

  indent_up(); // if

  indent(out) << "case " << id<<" of " << endl;

  indent_up(); // case

  // 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 do" << endl;

    indent_up(); // if

    indent(out) << "s <- ";

    generate_deserialize_field(out, *f_iter,str);

    out << endl;

    indent(out) << "read_"<<sname<<"_fields iprot rec{f_"<<sname<<"_"<< decapitalize((*f_iter)->get_name()) <<"=Just s}" << endl;

    out <<

      indent() << "else do" << endl;

    indent_up();

    indent(out) << "skip iprot "<< t << endl;

    indent(out) << "read_"<<sname<<"_fields iprot rec" << endl;

    indent_down(); // -do

    indent_down(); // -if

  }

  // In the default case we skip the field

  out <<

    indent() << "_ -> do" << endl;

  indent_up();

  indent(out) << "skip iprot "<<t<< endl;

  indent(out) << "readFieldEnd iprot" << endl;

  indent(out) << "read_"<<sname<<"_fields iprot rec" << endl;

  indent_down(); // -case

  indent_down(); // -if

  indent_down(); // -do

  indent_down();

  // read

  indent(out) << "read_"<<sname<<" iprot = do" << endl;

  indent_up();

  indent(out) << "readStructBegin iprot" << endl;

  indent(out) << "rec <- read_"<<sname<<"_fields iprot ("<<sname<<"{";

  bool first = true;

  for (f_iter = fields.begin(); f_iter != fields.end(); ++f_iter) {

    if(first)

      first=false;

    else

      out << ",";

    out << "f_" << sname << "_" << decapitalize((*f_iter)->get_name()) << "=Nothing";

  }

  out << "})" << endl;

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

  indent(out) << "return rec" << endl;

  indent_down();

}

void t_hs_generator::generate_hs_struct_writer(ofstream& out,

                                               t_struct* tstruct) {

  string name = type_name(tstruct);

  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) <<

    "write_"<<name<<" oprot rec = do" << endl;

  indent_up();

  indent(out) <<

    "writeStructBegin oprot \""<<name<<"\"" << endl;

  for (f_iter = fields.begin(); f_iter != fields.end(); ++f_iter) {

    // Write field header

    string mname = (*f_iter)->get_name();

    indent(out) <<

      "case f_" << name << "_" << mname << " rec of {Nothing -> return (); Just _v -> do" << endl;

    indent_up();

    indent(out) << "writeFieldBegin oprot (\""<< (*f_iter)->get_name()<<"\","

                <<type_to_enum((*f_iter)->get_type())<<","

                <<(*f_iter)->get_key()<<")" << endl;

    // Write field contents

    out << indent();

    generate_serialize_field(out, *f_iter, "_v");

    out << endl;

    // Write field closer

    indent(out) << "writeFieldEnd oprot}" << endl;

    indent_down();

  }

  // Write the struct map

  out <<

    indent() << "writeFieldStop oprot" << endl <<

    indent() << "writeStructEnd oprot" << endl;

  indent_down();

}

/**

 * Generates a thrift service.

 *

 * @param tservice The service definition

 */

void t_hs_generator::generate_service(t_service* tservice) {

  string f_service_name = get_out_dir()+capitalize(service_name_)+".hs";

  f_service_.open(f_service_name.c_str());

  f_service_ <<

    hs_autogen_comment() << endl <<

    "module " << capitalize(service_name_) << " where" << endl <<

    hs_imports() << endl;

  if(tservice->get_extends()){

    f_service_ <<

      "import qualified " << capitalize(tservice->get_extends()->get_name()) << endl;

  }

  f_service_ <<

     "import " << capitalize(program_name_) << "_Types" << endl <<

    "import qualified " << capitalize(service_name_) << "_Iface as Iface" << 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();

}

/**

 * Generates helper functions for a service.

 *

 * @param tservice The service to generate a header definition for

 */

void t_hs_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_hs_struct_definition(f_service_,ts, false);

    generate_hs_function_helpers(*f_iter);

  }

}

/**

 * Generates a struct and helpers for a function.

 *

 * @param tfunction The function

 */

void t_hs_generator::generate_hs_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_hs_struct_definition(f_service_,&result, false);

}

/**

 * Generates a service interface definition.

 *

 * @param tservice The service to generate a header definition for

 */

void t_hs_generator::generate_service_interface(t_service* tservice) {

  string f_iface_name = get_out_dir()+capitalize(service_name_)+"_Iface.hs";

  f_iface_.open(f_iface_name.c_str());

  indent(f_iface_) << "module " << capitalize(service_name_) << "_Iface where" << endl;

  indent(f_iface_) <<

    hs_imports() << endl <<

    "import " << capitalize(program_name_) << "_Types" << endl <<

    endl;

  if (tservice->get_extends() != NULL) {

    string extends = type_name(tservice->get_extends());

    indent(f_iface_) << "import " << extends <<"_Iface" << endl;

    indent(f_iface_) << "class "<< extends << "_Iface a => " << capitalize(service_name_) << "_Iface a where" << endl;

  } else {

    f_iface_ << indent() << "class " << capitalize(service_name_) << "_Iface a where" << endl;

  }

  indent_up();

  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,true);

    f_iface_ <<

      indent() << decapitalize((*f_iter)->get_name()) << " :: a -> " << ft  << endl;

  }

  indent_down();

  f_iface_.close();

}

/**

 * Generates a service client definition. Note that in Haskell, the client doesn't implement iface. This is because

 * The client does not (and should not have to) deal with arguments being Nothing.

 *

 * @param tservice The service to generate a server for.

 */

void t_hs_generator::generate_service_client(t_service* tservice) {

  string f_client_name = get_out_dir()+capitalize(service_name_)+"_Client.hs";

  f_client_.open(f_client_name.c_str());

  vector<t_function*> functions = tservice->get_functions();

  vector<t_function*>::const_iterator f_iter;

  string extends = "";

  string exports="";

  bool first = true;

  for (f_iter = functions.begin(); f_iter != functions.end(); ++f_iter) {

    if(first)

      first=false;

    else

      exports+=",";

    string funname = (*f_iter)->get_name();

    exports+=funname;

  }

  indent(f_client_) << "module " << capitalize(service_name_) << "_Client("<<exports<<") where" << endl;

  if (tservice->get_extends() != NULL) {

    extends = type_name(tservice->get_extends());

    indent(f_client_) << "import " << extends << "_Client" << endl;

  }

  indent(f_client_) << "import Data.IORef" << endl;

  indent(f_client_) << hs_imports() << endl;

  indent(f_client_) << "import " << capitalize(program_name_) << "_Types" << endl;

  indent(f_client_) << "import " << capitalize(service_name_) << endl;

  // DATS RITE A GLOBAL VAR

  indent(f_client_) << "seqid = newIORef 0" << endl;

  // Generate client method implementations

  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();

    string fargs = "";

    for (fld_iter = fields.begin(); fld_iter != fields.end(); ++fld_iter) {

      fargs+= " arg_" + decapitalize((*fld_iter)->get_name());

    }

    // Open function

    indent(f_client_) << funname << " (ip,op)" <<  fargs << " = do" << endl;

    indent_up();

    indent(f_client_) <<  "send_" << funname << " op" << fargs;

    f_client_ << endl;

    if (!(*f_iter)->is_oneway()) {

      f_client_ << indent();

      f_client_ <<

        "recv_" << funname << " ip" << endl;

    }

    indent_down();

    indent(f_client_) <<

      "send_" << funname << " op" << fargs << " = do" << endl;

    indent_up();

    indent(f_client_) << "seq <- seqid" << endl;

    indent(f_client_) << "seqn <- readIORef seq" << endl;

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

    // Serialize the request header

    f_client_ <<

      indent() << "writeMessageBegin op (\"" << (*f_iter)->get_name() << "\", M_CALL, seqn)" << endl;

    f_client_ << indent() << "write_" << argsname << " op ("<<argsname<<"{";

    bool first = true;

    for (fld_iter = fields.begin(); fld_iter != fields.end(); ++fld_iter) {

      if(first)

        first=false;

      else

        f_client_ << ",";

      f_client_ << "f_" << argsname <<"_" << (*fld_iter)->get_name() << "=Just arg_" << (*fld_iter)->get_name();

    }

    f_client_ << "})" << endl;

    // Write to the stream

    f_client_ <<

      indent() << "writeMessageEnd op" << endl <<

      indent() << "tFlush (getTransport op)" << endl;

    indent_down();

    if (!(*f_iter)->is_oneway()) {

      std::string resultname = capitalize((*f_iter)->get_name() + "_result");

      t_struct noargs(program_);

      std::string funname = string("recv_") + (*f_iter)->get_name();

      t_function recv_function((*f_iter)->get_returntype(),

                               funname,

                               &noargs);

      // Open function

      f_client_ <<

        indent() << funname << " ip = do" << endl;

      indent_up(); // fun

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

      f_client_ <<

        indent() << "(fname, mtype, rseqid) <- readMessageBegin ip" << endl;

      f_client_ <<

        indent() << "if mtype == M_EXCEPTION then do" << endl <<

        indent() << "  x <- readAppExn ip" << endl <<

        indent() << "  readMessageEnd ip" << endl;

      f_client_ <<

        indent() << "  throw x" << endl;

      f_client_ <<

        indent() << "  else return ()" << endl;

      t_struct* xs = (*f_iter)->get_xceptions();

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

      f_client_ <<

        indent() << "res <- read_" << resultname << " ip" << endl;

      f_client_ <<

        indent() << "readMessageEnd ip" << endl;

      // Careful, only return _result if not a void function

      if (!(*f_iter)->get_returntype()->is_void()) {

        f_client_ <<

          indent() << "case f_" << resultname << "_success res of" << endl;

        indent_up(); // case

        indent(f_client_) << "Just v -> return v" << endl;

        indent(f_client_) << "Nothing -> do" << endl;

        indent_up(); // none

      }

      vector<t_field*>::const_iterator x_iter;

      for (x_iter = xceptions.begin(); x_iter != xceptions.end(); ++x_iter) {

        f_client_ <<

          indent() << "case f_"<< resultname << "_" << (*x_iter)->get_name() << " res of" << endl;

        indent_up(); //case

        indent(f_client_) << "Nothing -> return ()" << endl;

        indent(f_client_) << "Just _v -> throw _v" << endl;

        indent_down(); //-case

      }

      // Careful, only return _result if not a void function

      if ((*f_iter)->get_returntype()->is_void()) {

        indent(f_client_) <<

          "return ()" << endl;

      } else {

        f_client_ <<

          indent() << "throw (AppExn AE_MISSING_RESULT \"" << (*f_iter)->get_name() << " failed: unknown result\")" << endl;

        indent_down(); //-none

        indent_down(); //-case

      }

      // Close function

      indent_down(); //-fun

    }

  }

  f_client_.close();

}

/**

 * Generates a service server definition.

 *

 * @param tservice The service to generate a server for.

 */

void t_hs_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 process subfunctions

  for (f_iter = functions.begin(); f_iter != functions.end(); ++f_iter) {

    generate_process_function(tservice, *f_iter);

  }

  indent(f_service_) << "proc handler (iprot,oprot) (name,typ,seqid) = case name of" << endl;

  indent_up();

  for (f_iter = functions.begin(); f_iter != functions.end(); ++f_iter) {

    string fname = (*f_iter)->get_name();

    indent(f_service_) << "\""<<fname<<"\" -> process_" << decapitalize(fname) << " (seqid,iprot,oprot,handler)" << endl;

  }

  indent(f_service_) << "_ -> ";

  if(tservice->get_extends() != NULL){

    f_service_ << type_name(tservice->get_extends()) << ".proc handler (iprot,oprot) (name,typ,seqid)" << endl;

  } else {

    f_service_ << "do" << endl;

    indent_up();

    indent(f_service_) << "skip iprot T_STRUCT" << endl;

    indent(f_service_) << "readMessageEnd iprot" << endl;

    indent(f_service_) << "writeMessageBegin oprot (name,M_EXCEPTION,seqid)" << endl;

    indent(f_service_) << "writeAppExn oprot (AppExn AE_UNKNOWN_METHOD (\"Unknown function \" ++ name))" << endl;

    indent(f_service_) << "writeMessageEnd oprot" << endl;

    indent(f_service_) << "tFlush (getTransport oprot)" << endl;

    indent_down();

  }

  indent_down();

  // Generate the server implementation

  indent(f_service_) <<

    "process handler (iprot, oprot) = do" << endl;

  indent_up();

  f_service_ <<

    indent() << "(name, typ, seqid) <- readMessageBegin iprot" << endl;

  f_service_ << indent() << "proc handler (iprot,oprot) (name,typ,seqid)" << endl;

  indent(f_service_) << "return True" << endl;

  indent_down();

}

/**

 * Generates a process function definition.

 *

 * @param tfunction The function to write a dispatcher for

 */

void t_hs_generator::generate_process_function(t_service* tservice,

                                               t_function* tfunction) {

  // Open function

  indent(f_service_) <<

    "process_" << tfunction->get_name() << " (seqid, iprot, oprot, handler) = do" << endl;

  indent_up();

  string argsname = capitalize(tfunction->get_name()) + "_args";

  string resultname = capitalize(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;

  f_service_ <<

    indent() << "args <- read_" << argsname << " iprot" << endl;

  f_service_ <<

    indent() << "readMessageEnd iprot" << endl;

  t_struct* xs = tfunction->get_xceptions();

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

  vector<t_field*>::const_iterator x_iter;

  int n = xceptions.size();

  if (!tfunction->is_oneway()){

    if(!tfunction->get_returntype()->is_void()){

      n++;

    }

    indent(f_service_) << "rs <- return (" << resultname;

    for(int i=0; i<n;i++){

      f_service_ << " Nothing";

    }

    f_service_ << ")" << endl;

  }

  indent(f_service_) << "res <- ";

  // Try block for a function with exceptions

  if (xceptions.size() > 0) {

    for(unsigned int i=0;i<xceptions.size();i++){

      f_service_ << "(Control.Exception.catch" << endl;

      indent_up();

      f_service_ << indent();

    }

  }

  f_service_ << "(do" << endl;

  indent_up();

  f_service_ << indent();

  if (!tfunction->is_oneway() && !tfunction->get_returntype()->is_void()){

    f_service_ << "res <- ";

  }

  f_service_ << "Iface." << tfunction->get_name() << " handler";

  for (f_iter = fields.begin(); f_iter != fields.end(); ++f_iter) {

    f_service_ <<  " (f_" << argsname <<  "_" << (*f_iter)->get_name() << " args)";

  }