text: /*
   * 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 std::map;
  using std::ofstream;
  using std::ostringstream;
  using std::string;
  using std::stringstream;
  using std::vector;
  
  static const string endl = "\n"; // avoid ostream << std::endl flushes
  
  /**
   * Haskell code generator.
   *
   */
  class t_hs_generator : public t_oop_generator {
  public:
    t_hs_generator(t_program* program,
                   const map<string, string>& parsed_options,
                   const string& option_string)
      : t_oop_generator(program) {
      (void)parsed_options;
      (void)option_string;
      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);
  
    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(ofstream& out,
                                       t_struct* tstruct,
                                       bool is_xception = false,
                                       bool helper = false);
  
    void generate_hs_struct_reader(ofstream& out, t_struct* tstruct);
  
    void generate_hs_struct_writer(ofstream& out, t_struct* tstruct);
  
    void generate_hs_struct_arbitrary(ofstream& out, t_struct* tstruct);
  
    void generate_hs_function_helpers(t_function* tfunction);
  
    void generate_hs_typemap(ofstream& out, t_struct* tstruct);
  
    void generate_hs_default(ofstream& out, t_struct* tstruct);
  
    /**
     * 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(ofstream& out, t_field* tfield, string prefix);
  
    void generate_deserialize_struct(ofstream& out, t_struct* tstruct, string name = "");
  
    void generate_deserialize_container(ofstream& out, t_type* ttype, string arg = "");
  
    void generate_deserialize_set_element(ofstream& out, t_set* tset);
  
    void generate_deserialize_list_element(ofstream& out, t_list* tlist, string prefix = "");
  
    void generate_deserialize_type(ofstream& out, t_type* type, string arg = "");
  
    void generate_serialize_type(ofstream& out, t_type* type, string name = "");
  
    void generate_serialize_struct(ofstream& out, t_struct* tstruct, string prefix = "");
  
    void generate_serialize_container(ofstream& out, t_type* ttype, string prefix = "");
  
    void generate_serialize_map_element(ofstream& out, t_map* tmap, string kiter, string viter);
  
    void generate_serialize_set_element(ofstream& out, t_set* tmap, string iter);
  
    void generate_serialize_list_element(ofstream& out, t_list* tlist, string iter);
  
    /**
     * Helper rendering functions
     */
  
    string hs_autogen_comment();
    string hs_language_pragma();
    string hs_imports();
  
    string type_name(t_type* ttype, string function_prefix = "");
  
    string field_name(string tname, string fname);
  
    string function_type(t_function* tfunc,
                         bool options = false,
                         bool io = false,
                         bool method = false);
  
    string type_to_enum(t_type* ttype);
  
    string type_to_default(t_type* ttype);
  
    string render_hs_type(t_type* type, bool needs_parens);
  
    string type_to_constructor(t_type* ttype);
  
    string render_hs_type_for_function_name(t_type* type);
  
  private:
    ofstream f_types_;
    ofstream f_consts_;
    ofstream f_service_;
    ofstream f_iface_;
    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_language_pragma() << endl;
    f_types_ << hs_autogen_comment() << endl;
    f_types_ << "module " << pname << "_Types where" << endl;
    f_types_ << hs_imports() << endl;
  
    f_consts_ << hs_language_pragma() << endl;
    f_consts_ << hs_autogen_comment() << endl;
    f_consts_ << "module " << pname << "_Consts where" << endl;
    f_consts_ << hs_imports() << endl;
    f_consts_ << "import " << pname << "_Types" << endl;
  }
  
  string t_hs_generator::hs_language_pragma() {
    return string(
        "{-# LANGUAGE DeriveDataTypeable #-}\n"
        "{-# LANGUAGE DeriveGeneric #-}\n"
        "{-# LANGUAGE OverloadedStrings #-}\n"
        "{-# OPTIONS_GHC -fno-warn-missing-fields #-}\n"
        "{-# OPTIONS_GHC -fno-warn-missing-signatures #-}\n"
        "{-# OPTIONS_GHC -fno-warn-name-shadowing #-}\n"
        "{-# OPTIONS_GHC -fno-warn-unused-imports #-}\n"
        "{-# OPTIONS_GHC -fno-warn-unused-matches #-}\n");
  }
  
  /**
   * Autogen'd comment
   */
  string t_hs_generator::hs_autogen_comment() {
    return 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_hs_generator::hs_imports() {
    const vector<t_program*>& includes = program_->get_includes();
    string result = string(
        "import Prelude (($), (.), (>>=), (==), (++))\n"
        "import qualified Prelude as P\n"
        "import qualified Control.Exception as X\n"
        "import qualified Control.Monad as M ( liftM, ap, when )\n"
        "import Data.Functor ( (<$>) )\n"
        "import qualified Data.ByteString.Lazy as LBS\n"
        "import qualified Data.Hashable as H\n"
        "import qualified Data.Int as I\n"
        "import qualified Data.Maybe as M (catMaybes)\n"
        "import qualified Data.Text.Lazy.Encoding as E ( decodeUtf8, encodeUtf8 )\n"
        "import qualified Data.Text.Lazy as LT\n"
        "import qualified GHC.Generics as G (Generic)\n"
        "import qualified Data.Typeable as TY ( Typeable )\n"
        "import qualified Data.HashMap.Strict as Map\n"
        "import qualified Data.HashSet as Set\n"
        "import qualified Data.Vector as Vector\n"
        "import qualified Test.QuickCheck.Arbitrary as QC ( Arbitrary(..) )\n"
        "import qualified Test.QuickCheck as QC ( elements )\n"
        "\n"
        "import qualified Thrift as T\n"
        "import qualified Thrift.Types as T\n"
        "import qualified Thrift.Arbitraries as T\n"
        "\n");
  
    for (size_t i = 0; i < includes.size(); ++i)
      result += "import qualified " + capitalize(includes[i]->get_name()) + "_Types\n";
  
    if (includes.size() > 0)
      result += "\n";
  
    return result;
  }
  
  /**
   * 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) {
    string tname = capitalize(ttypedef->get_symbolic());
    string tdef = render_hs_type(ttypedef->get_type(), false);
    indent(f_types_) << "type " << tname << " = " << tdef << endl;
    f_types_ << 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());
      f_types_ << (first ? "" : "|");
      f_types_ << name;
      first = false;
    }
    indent(f_types_) << "deriving (P.Show, P.Eq, G.Generic, TY.Typeable, P.Ord, P.Bounded)" << endl;
    indent_down();
  
    string ename = capitalize(tenum->get_name());
  
    indent(f_types_) << "instance P.Enum " << ename << " 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) {
      int value = (*c_iter)->get_value();
      string name = capitalize((*c_iter)->get_name());
      indent(f_types_) << 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) {
      int value = (*c_iter)->get_value();
      string name = capitalize((*c_iter)->get_name());
      indent(f_types_) << value << " -> " << name << endl;
    }
    indent(f_types_) << "_ -> X.throw T.ThriftException" << endl;
    indent_down();
    indent_down();
  
    indent(f_types_) << "instance H.Hashable " << ename << " where" << endl;
    indent_up();
    indent(f_types_) << "hashWithSalt salt = H.hashWithSalt salt P.. P.fromEnum" << endl;
    indent_down();
  
    indent(f_types_) << "instance QC.Arbitrary " << ename << " where" << endl;
    indent_up();
    indent(f_types_) << "arbitrary = QC.elements (P.enumFromTo P.minBound P.maxBound)" << endl;
    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;
    f_consts_ << 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) {
    if (value == NULL)
      return type_to_default(type);
  
    type = get_true_type(type);
    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 ? "P.True" : "P.False");
        break;
  
      case t_base_type::TYPE_I8:
      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();
      for (vector<t_enum_value*>::iterator c_iter = constants.begin(); c_iter != constants.end();
           ++c_iter) {
        int val = (*c_iter)->get_value();
        if (val == value->get_integer()) {
          t_program* prog = type->get_program();
          if (prog != NULL && prog != program_)
            out << capitalize(prog->get_name()) << "_Types.";
          out << capitalize((*c_iter)->get_name());
          break;
        }
      }
  
    } else if (type->is_struct() || type->is_xception()) {
      string cname = type_name(type);
      out << "default_" << cname << "{";
  
      const vector<t_field*>& fields = ((t_struct*)type)->get_members();
      const map<t_const_value*, t_const_value*>& val = value->get_map();
  
      bool first = true;
      for (map<t_const_value*, t_const_value*>::const_iterator v_iter = val.begin();
           v_iter != val.end();
           ++v_iter) {
        t_field* field = NULL;
  
        for (vector<t_field*>::const_iterator f_iter = fields.begin(); f_iter != fields.end();
             ++f_iter)
          if ((*f_iter)->get_name() == v_iter->first->get_string())
            field = (*f_iter);
  
        if (field == NULL)
          throw "type error: " + cname + " has no field " + v_iter->first->get_string();
  
        string fname = v_iter->first->get_string();
        string const_value = render_const_value(field->get_type(), v_iter->second);
  
        out << (first ? "" : ", ");
        out << field_name(cname, fname) << " = ";
        if (field->get_req() == t_field::T_OPTIONAL || ((t_type*)field->get_type())->is_xception()) {
          out << "P.Just ";
        }
        out << const_value;
        first = false;
      }
  
      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);
        out << (first ? "" : ",");
        out << "(" << key << "," << val << ")";
        first = false;
      }
      out << "])";
  
    } else if (type->is_list() || type->is_set()) {
      t_type* etype = type->is_list() ? ((t_list*)type)->get_elem_type()
                                      : ((t_set*)type)->get_elem_type();
  
      const vector<t_const_value*>& val = value->get_list();
      vector<t_const_value*>::const_iterator v_iter;
  
      if (type->is_set())
        out << "(Set.fromList [";
      else
        out << "(Vector.fromList [";
  
      bool first = true;
      for (v_iter = val.begin(); v_iter != val.end(); ++v_iter) {
        out << (first ? "" : ",");
        out << render_const_value(etype, *v_iter);
        first = false;
      }
  
      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) {
    (void)helper;
    string tname = type_name(tstruct);
    string name = tstruct->get_name();
    const vector<t_field*>& members = tstruct->get_members();
  
    indent(out) << "data " << tname << " = " << tname;
    if (members.size() > 0) {
      indent_up();
      bool first = true;
      for (vector<t_field*>::const_iterator m_iter = members.begin(); m_iter != members.end();
           ++m_iter) {
        if (first) {
          indent(out) << "{ ";
          first = false;
        } else {
          indent(out) << ", ";
        }
        string mname = (*m_iter)->get_name();
        out << field_name(tname, mname) << " :: ";
        if ((*m_iter)->get_req() == t_field::T_OPTIONAL
            || ((t_type*)(*m_iter)->get_type())->is_xception()) {
          out << "P.Maybe ";
        }
        out << render_hs_type((*m_iter)->get_type(), true) << endl;
      }
      indent(out) << "}";
      indent_down();
    }
  
    out << " deriving (P.Show,P.Eq,G.Generic,TY.Typeable)" << endl;
  
    if (is_exception)
      out << "instance X.Exception " << tname << endl;
  
    indent(out) << "instance H.Hashable " << tname << " where" << endl;
    indent_up();
    indent(out) << "hashWithSalt salt record = salt";
    for (vector<t_field*>::const_iterator m_iter = members.begin(); m_iter != members.end();
         ++m_iter) {
      string mname = (*m_iter)->get_name();
      indent(out) << " `H.hashWithSalt` " << field_name(tname, mname) << " record";
    }
    indent(out) << endl;
    indent_down();
  
    generate_hs_struct_arbitrary(out, tstruct);
    generate_hs_struct_writer(out, tstruct);
    generate_hs_struct_reader(out, tstruct);
    generate_hs_typemap(out, tstruct);
    generate_hs_default(out, tstruct);
  }
  
  void t_hs_generator::generate_hs_struct_arbitrary(ofstream& out, t_struct* tstruct) {
    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) << "instance QC.Arbitrary " << tname << " where " << endl;
    indent_up();
    if (members.size() > 0) {
      indent(out) << "arbitrary = M.liftM " << tname;
      indent_up();
      indent_up();
      indent_up();
      indent_up();
      bool first = true;
      for (vector<t_field*>::const_iterator m_iter = members.begin(); m_iter != members.end();
           ++m_iter) {
        if (first) {
          first = false;
          out << " ";
        } else {
          indent(out) << "`M.ap`";
        }
        out << "(";
        if ((*m_iter)->get_req() == t_field::T_OPTIONAL
            || ((t_type*)(*m_iter)->get_type())->is_xception()) {
          out << "M.liftM P.Just ";
        }
        out << "QC.arbitrary)" << endl;
      }
      indent_down();
      indent_down();
      indent_down();
      indent_down();
  
      // Shrink
      indent(out) << "shrink obj | obj == default_" << tname << " = []" << endl;
      indent(out) << "           | P.otherwise = M.catMaybes" << endl;
      indent_up();
      first = true;
      for (vector<t_field*>::const_iterator m_iter = members.begin(); m_iter != members.end();
           ++m_iter) {
        if (first) {
          first = false;
          indent(out) << "[ ";
        } else {
          indent(out) << ", ";
        }
        string fname = field_name(tname, (*m_iter)->get_name());
        out << "if obj == default_" << tname;
        out << "{" << fname << " = " << fname << " obj} ";
        out << "then P.Nothing ";
        out << "else P.Just $ default_" << tname;
        out << "{" << fname << " = " << fname << " obj}" << endl;
      }
      indent(out) << "]" << endl;
      indent_down();
    } else { /* 0 == members.size() */
      indent(out) << "arbitrary = QC.elements [" << tname << "]" << endl;
    }
    indent_down();
  }
  
  /**
   * 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 id = tmp("_id");
    string val = tmp("_val");
  
    indent(out) << "to_" << sname << " :: T.ThriftVal -> " << sname << endl;
    indent(out) << "to_" << sname << " (T.TStruct fields) = " << sname << "{" << endl;
    indent_up();
  
    bool first = true;
  
    // Generate deserialization code for known cases
    for (vector<t_field*>::const_iterator f_iter = fields.begin(); f_iter != fields.end(); ++f_iter) {
      int32_t key = (*f_iter)->get_key();
      string etype = type_to_enum((*f_iter)->get_type());
      string fname = (*f_iter)->get_name();
  
      if (first) {
        first = false;
      } else {
        out << "," << endl;
      }
  
      // Fill in Field
      indent(out) << field_name(sname, fname) << " = ";
  
      out << "P.maybe (";
      if ((*f_iter)->get_req() == t_field::T_REQUIRED) {
        out << "P.error \"Missing required field: " << fname << "\"";
      } else {
        if (((*f_iter)->get_req() == t_field::T_OPTIONAL
             || ((t_type*)(*f_iter)->get_type())->is_xception()) && (*f_iter)->get_value() == NULL) {
          out << "P.Nothing";
        } else {
          out << field_name(sname, fname) << " default_" << sname;
        }
      }
      out << ") ";
  
      out << "(\\(_," << val << ") -> ";
      if ((*f_iter)->get_req() == t_field::T_OPTIONAL
          || ((t_type*)(*f_iter)->get_type())->is_xception())
        out << "P.Just ";
      generate_deserialize_field(out, *f_iter, val);
      out << ")";
      out << " (Map.lookup (" << key << ") fields)";
    }
  
    out << endl;
    indent(out) << "}" << endl;
    indent_down();
  
    // read
    string tmap = type_name(tstruct, "typemap_");
    indent(out) << "to_" << sname << " _ = P.error \"not a struct\"" << endl;
  
    indent(out) << "read_" << sname << " :: (T.Transport t, T.Protocol p) => p t -> P.IO " << sname
                << endl;
    indent(out) << "read_" << sname << " iprot = to_" << sname;
    out << " <$> T.readVal iprot (T.T_STRUCT " << tmap << ")" << endl;
  
    indent(out) << "decode_" << sname
                << " :: (T.Protocol p, T.Transport t) => p t -> LBS.ByteString -> " << sname << endl;
    indent(out) << "decode_" << sname << " iprot bs = to_" << sname << " $ ";
    out << "T.deserializeVal iprot (T.T_STRUCT " << tmap << ") bs" << endl;
  }
  
  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");
    string v = tmp("_v");
  
    indent(out) << "from_" << name << " :: " << name << " -> T.ThriftVal" << endl;
    indent(out) << "from_" << name << " record = T.TStruct $ Map.fromList ";
    indent_up();
  
    // Get Exceptions
    bool hasExn = false;
    for (vector<t_field*>::const_iterator f_iter = fields.begin(); f_iter != fields.end(); ++f_iter) {
      if (((t_type*)(*f_iter)->get_type())->is_xception()) {
        hasExn = true;
        break;
      }
    }
  
    bool isfirst = true;
    if (hasExn) {
      out << endl;
      indent(out) << "(let exns = M.catMaybes ";
      indent_up();
      for (vector<t_field*>::const_iterator f_iter = fields.begin(); f_iter != fields.end();
           ++f_iter) {
        if (((t_type*)(*f_iter)->get_type())->is_xception()) {
          if (isfirst) {
            out << "[ ";
            isfirst = false;
          } else {
            out << ", ";
          }
          string mname = (*f_iter)->get_name();
          int32_t key = (*f_iter)->get_key();
          out << "(\\" << v << " -> (" << key << ", (\"" << mname << "\",";
          generate_serialize_type(out, (*f_iter)->get_type(), v);
          out << "))) <$> " << field_name(name, mname) << " record";
        }
      }
      if (!isfirst) {
        out << "]" << endl;
      }
      indent_down();
      indent(out) << "in if P.not (P.null exns) then exns else ";
      indent_up();
    } else {
      out << "$ ";
    }
  
    out << "M.catMaybes" << endl;
    // Get the Rest
    isfirst = true;
    for (vector<t_field*>::const_iterator f_iter = fields.begin(); f_iter != fields.end(); ++f_iter) {
      // Write field header
      if (isfirst) {
        indent(out) << "[ ";
        isfirst = false;
      } else {
        indent(out) << ", ";
      }
      string mname = (*f_iter)->get_name();
      int32_t key = (*f_iter)->get_key();
      out << "(\\";
      out << v << " -> ";
      if ((*f_iter)->get_req() != t_field::T_OPTIONAL
          && !((t_type*)(*f_iter)->get_type())->is_xception()) {
        out << "P.Just ";
      }
      out << "(" << key << ", (\"" << mname << "\",";
      generate_serialize_type(out, (*f_iter)->get_type(), v);
      out << "))) ";
      if ((*f_iter)->get_req() != t_field::T_OPTIONAL
          && !((t_type*)(*f_iter)->get_type())->is_xception()) {
        out << "$";
      } else {
        out << "<$>";
      }
      out << " " << field_name(name, mname) << " record" << endl;
    }
  
    // Write the struct map
    if (isfirst) {
      indent(out) << "[]" << endl;
    } else {
      indent(out) << "]" << endl;
    }
    if (hasExn) {
      indent(out) << ")" << endl;
      indent_down();
    }
    indent_down();
  
    // write
    indent(out) << "write_" << name << " :: (T.Protocol p, T.Transport t) => p t -> " << name
                << " -> P.IO ()" << endl;
    indent(out) << "write_" << name << " oprot record = T.writeVal oprot $ from_";
    out << name << " record" << endl;
  
    // encode
    indent(out) << "encode_" << name << " :: (T.Protocol p, T.Transport t) => p t -> " << name
                << " -> LBS.ByteString" << endl;
    indent(out) << "encode_" << name << " oprot record = T.serializeVal oprot $ ";
    out << "from_" << name << " record" << endl;
  }
  
  /**
   * 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_language_pragma() << endl;
    f_service_ << hs_autogen_comment() << endl;
    f_service_ << "module " << capitalize(service_name_) << " where" << endl;
    f_service_ << 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;
    f_service_ << "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;
    indent(f_service_) << 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_, field_name(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);
  }
  
  /**
   * Generate the map from field names to (type, id)
   * @param tstruct the Struct
   */
  void t_hs_generator::generate_hs_typemap(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;
  
    indent(out) << "typemap_" << name << " :: T.TypeMap" << endl;
    indent(out) << "typemap_" << name << " = Map.fromList [";
    bool first = true;
    for (vector<t_field*>::const_iterator f_iter = fields.begin(); f_iter != fields.end(); ++f_iter) {
      string mname = (*f_iter)->get_name();
      if (!first) {
        out << ",";
      }
  
      t_type* type = get_true_type((*f_iter)->get_type());
      int32_t key = (*f_iter)->get_key();
      out << "(" << key << ",(\"" << mname << "\"," << type_to_enum(type) << "))";
      first = false;
    }
    out << "]" << endl;
  }
  
  /**
   * generate the struct with default values filled in
   * @param tstruct the Struct
   */
  void t_hs_generator::generate_hs_default(ofstream& out, t_struct* tstruct) {
    string name = type_name(tstruct);
    string fname = type_name(tstruct, "default_");
    const vector<t_field*>& fields = tstruct->get_sorted_members();
  
    indent(out) << fname << " :: " << name << endl;
    indent(out) << fname << " = " << name << "{" << endl;
    indent_up();
    bool first = true;
    for (vector<t_field*>::const_iterator f_iter = fields.begin(); f_iter != fields.end(); ++f_iter) {
      string mname = (*f_iter)->get_name();
      if (first) {
        first = false;
      } else {
        out << "," << endl;
      }
  
      t_type* type = get_true_type((*f_iter)->get_type());
      t_const_value* value = (*f_iter)->get_value();
      indent(out) << field_name(name, mname) << " = ";
      if ((*f_iter)->get_req() == t_field::T_OPTIONAL
          || ((t_type*)(*f_iter)->get_type())->is_xception()) {
        if (value == NULL) {
          out << "P.Nothing";
        } else {
          out << "P.Just " << render_const_value(type, value);
        }
      } else {
        out << render_const_value(type, value);
      }
    }
    out << "}" << endl;
    indent_down();
  }
  
  /**
   * 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());
  
    f_iface_ << hs_language_pragma() << endl;
    f_iface_ << hs_autogen_comment() << endl;
  
    f_iface_ << "module " << capitalize(service_name_) << "_Iface where" << endl;
  
    f_iface_ << hs_imports() << endl;
    f_iface_ << "import " << capitalize(program_name_) << "_Types" << endl;
    f_iface_ << endl;
  
    string sname = capitalize(service_name_);
    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 => " << sname << "_Iface a where" << endl;
  
    } else {
      indent(f_iface_) << "class " << sname << "_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);
      indent(f_iface_) << 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());
    f_client_ << hs_language_pragma() << endl;
    f_client_ << hs_autogen_comment() << endl;
  
    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) {
      exports += (first ? "" : ",");
      string funname = (*f_iter)->get_name();
      exports += decapitalize(funname);
      first = false;
    }
  
    string sname = capitalize(service_name_);
    indent(f_client_) << "module " << sname << "_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 qualified Data.IORef as R" << 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 = R.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_" + (*fld_iter)->get_name();
  
      // Open function
      indent(f_client_) << decapitalize(funname) << " (ip,op)" << fargs << " = do" << endl;
      indent_up();
      indent(f_client_) << "send_" << funname << " op" << fargs;
  
      f_client_ << endl;
  
      if (!(*f_iter)->is_oneway())
        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 <- R.readIORef seq" << endl;
      string argsname = capitalize((*f_iter)->get_name() + "_args");
  
      // Serialize the request header
      string fname = (*f_iter)->get_name();
      string msgType = (*f_iter)->is_oneway() ? "T.M_ONEWAY" : "T.M_CALL";
      indent(f_client_) << "T.writeMessageBegin op (\"" << fname << "\", " << msgType << ", seqn)"
                        << endl;
      indent(f_client_) << "write_" << argsname << " op (" << argsname << "{";
  
      bool first = true;
      for (vector<t_field*>::const_iterator fld_iter = fields.begin(); fld_iter != fields.end();
           ++fld_iter) {
        string fieldname = (*fld_iter)->get_name();
        f_client_ << (first ? "" : ",");
        f_client_ << field_name(argsname, fieldname) << "=";
        if ((*fld_iter)->get_req() == t_field::T_OPTIONAL
            || ((t_type*)(*fld_iter)->get_type())->is_xception())
          f_client_ << "P.Just ";
        f_client_ << "arg_" << fieldname;
        first = false;
      }
      f_client_ << "})" << endl;
      indent(f_client_) << "T.writeMessageEnd op" << endl;
  
      // Write to the stream
      indent(f_client_) << "T.tFlush (T.getTransport op)" << endl;
      indent_down();
  
      if (!(*f_iter)->is_oneway()) {
        string resultname = capitalize((*f_iter)->get_name() + "_result");
        t_struct noargs(program_);
  
        string funname = string("recv_") + (*f_iter)->get_name();
        t_function recv_function((*f_iter)->get_returntype(), funname, &noargs);
  
        // Open function
        indent(f_client_) << funname << " ip = do" << endl;
        indent_up();
  
        indent(f_client_) << "(fname, mtype, rseqid) <- T.readMessageBegin ip" << endl;
        indent(f_client_) << "M.when (mtype == T.M_EXCEPTION) $ do { exn <- T.readAppExn ip ; "
                             "T.readMessageEnd ip ; X.throw exn }" << endl;
  
        indent(f_client_) << "res <- read_" << resultname << " ip" << endl;
        indent(f_client_) << "T.readMessageEnd ip" << endl;
  
        t_struct* xs = (*f_iter)->get_xceptions();
        const vector<t_field*>& xceptions = xs->get_members();
  
        for (vector<t_field*>::const_iterator x_iter = xceptions.begin(); x_iter != xceptions.end();
             ++x_iter) {
          indent(f_client_) << "P.maybe (P.return ()) X.throw ("
                            << field_name(resultname, (*x_iter)->get_name()) << " res)" << endl;
        }
  
        if (!(*f_iter)->get_returntype()->is_void())
          indent(f_client_) << "P.return $ " << field_name(resultname, "success") << " res" << endl;
        else
          indent(f_client_) << "P.return ()" << endl;
  
        // Close function
        indent_down();
      }
    }
  
    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_) << "_ <- T.readVal iprot (T.T_STRUCT Map.empty)" << endl;
      indent(f_service_) << "T.writeMessageBegin oprot (name,T.M_EXCEPTION,seqid)" << endl;
      indent(f_service_) << "T.writeAppExn oprot (T.AppExn T.AE_UNKNOWN_METHOD (\"Unknown function "
                            "\" ++ LT.unpack name))" << endl;
      indent(f_service_) << "T.writeMessageEnd oprot" << endl;
      indent(f_service_) << "T.tFlush (T.getTransport oprot)" << endl;
      indent_down();
    }
  
    indent_down();
  
    // Generate the server implementation
    indent(f_service_) << "process handler (iprot, oprot) = do" << endl;
    indent_up();
  
    indent(f_service_) << "(name, typ, seqid) <- T.readMessageBegin iprot" << endl;
    indent(f_service_) << "proc_ handler (iprot,oprot) (name,typ,seqid)" << endl;
    indent(f_service_) << "T.readMessageEnd iprot" << endl;
    indent(f_service_) << "P.return P.True" << endl;
    indent_down();
  }
  
  bool hasNoArguments(t_function* func) {
    return (func->get_arglist()->get_members().empty());
  }
  
  string t_hs_generator::render_hs_type_for_function_name(t_type* type) {
    string type_str = render_hs_type(type, false);
    std::string::size_type found = -1;
  
    while (true) {
      found = type_str.find_first_of("[]. ", found + 1);
      if (string::npos == size_t(found)) {
        break;
      }
  
      if (type_str[found] == '.')
        type_str[found] = '_';
      else
        type_str[found] = 'Z';
    }
    return type_str;
  }
  
  /**
   * 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) {
    (void)tservice;
    // Open function
    string funname = decapitalize(tfunction->get_name());
    indent(f_service_) << "process_" << funname << " (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 vector<t_field*>& fields = arg_struct->get_members();
    vector<t_field*>::const_iterator f_iter;
  
    indent(f_service_) << "args <- read_" << argsname << " iprot" << endl;
  
    t_struct* xs = tfunction->get_xceptions();
    const vector<t_field*>& xceptions = xs->get_members();
    vector<t_field*>::const_iterator x_iter;
  
    size_t n = xceptions.size() + 1;
    // Try block for a function with exceptions
    if (n > 0) {
      for (size_t i = 0; i < n; i++) {
        indent(f_service_) << "(X.catch" << endl;
        indent_up();
      }
    }
  
    if (n > 0) {
      indent(f_service_) << "(do" << endl;
      indent_up();
    }
    indent(f_service_);
  
    if (!tfunction->is_oneway() && !tfunction->get_returntype()->is_void())
      f_service_ << "val <- ";
  
    f_service_ << "Iface." << decapitalize(tfunction->get_name()) << " handler";
    for (f_iter = fields.begin(); f_iter != fields.end(); ++f_iter)
      f_service_ << " (" << field_name(argsname, (*f_iter)->get_name()) << " args)";
  
    if (!tfunction->is_oneway() && !tfunction->get_returntype()->is_void()) {
      f_service_ << endl;
      indent(f_service_) << "let res = default_" << resultname << "{"
                         << field_name(resultname, "success") << " = val}";
  
    } else if (!tfunction->is_oneway()) {
      f_service_ << endl;
      indent(f_service_) << "let res = default_" << resultname;
    }
    f_service_ << endl;
  
    // Shortcut out here for oneway functions
    if (tfunction->is_oneway()) {
      indent(f_service_) << "P.return ()";
    } else {
      indent(f_service_) << "T.writeMessageBegin oprot (\"" << tfunction->get_name()
                         << "\", T.M_REPLY, seqid)" << endl;
      indent(f_service_) << "write_" << resultname << " oprot res" << endl;
      indent(f_service_) << "T.writeMessageEnd oprot" << endl;
      indent(f_service_) << "T.tFlush (T.getTransport oprot)";
    }
    if (n > 0) {
      f_service_ << ")";
      indent_down();
    }
    f_service_ << endl;
  
    if (n > 0) {
      for (x_iter = xceptions.begin(); x_iter != xceptions.end(); ++x_iter) {
        indent(f_service_) << "(\\e  -> do" << endl;
        indent_up();
  
        if (!tfunction->is_oneway()) {
          indent(f_service_) << "let res = default_" << resultname << "{"
                             << field_name(resultname, (*x_iter)->get_name()) << " = P.Just e}"
                             << endl;
          indent(f_service_) << "T.writeMessageBegin oprot (\"" << tfunction->get_name()
                             << "\", T.M_REPLY, seqid)" << endl;
          indent(f_service_) << "write_" << resultname << " oprot res" << endl;
          indent(f_service_) << "T.writeMessageEnd oprot" << endl;
          indent(f_service_) << "T.tFlush (T.getTransport oprot)";
        } else {
          indent(f_service_) << "P.return ()";
        }
  
        f_service_ << "))" << endl;
        indent_down();
        indent_down();
      }
      indent(f_service_) << "((\\_ -> do" << endl;
      indent_up();
  
      if (!tfunction->is_oneway()) {
        indent(f_service_) << "T.writeMessageBegin oprot (\"" << tfunction->get_name()
                           << "\", T.M_EXCEPTION, seqid)" << endl;
        indent(f_service_) << "T.writeAppExn oprot (T.AppExn T.AE_UNKNOWN \"\")" << endl;
        indent(f_service_) << "T.writeMessageEnd oprot" << endl;
        indent(f_service_) << "T.tFlush (T.getTransport oprot)";
      } else {
        indent(f_service_) << "P.return ()";
      }
  
      f_service_ << ") :: X.SomeException -> P.IO ()))" << endl;
      indent_down();
      indent_down();
    }
    // Close function
    indent_down();
  }
  
  /**
   * Deserializes a field of any type.
   */
  void t_hs_generator::generate_deserialize_field(ofstream& out, t_field* tfield, string prefix) {
    (void)prefix;
    t_type* type = tfield->get_type();
    generate_deserialize_type(out, type, prefix);
  }
  
  /**
   * Deserializes a field of any type.
   */
  void t_hs_generator::generate_deserialize_type(ofstream& out, t_type* type, string arg) {
    type = get_true_type(type);
    string val = tmp("_val");
    out << "(case " << arg << " of {" << type_to_constructor(type) << " " << val << " -> ";
  
    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, val);
  
    } else if (type->is_container()) {
      generate_deserialize_container(out, type, val);
  
    } else if (type->is_base_type()) {
      t_base_type::t_base tbase = ((t_base_type*)type)->get_base();
      if (tbase == t_base_type::TYPE_STRING && !((t_base_type*)type)->is_binary()) {
        out << "E.decodeUtf8 ";
      }
      out << val;
    } else if (type->is_enum()) {
      out << "P.toEnum $ P.fromIntegral " << val;
  
    } else {
      throw "DO NOT KNOW HOW TO DESERIALIZE TYPE " + type->get_name();
    }
    out << "; _ -> P.error \"wrong type\"})";
  }
  
  /**
   * Generates an unserializer for a struct, calling read()
   */
  void t_hs_generator::generate_deserialize_struct(ofstream& out, t_struct* tstruct, string name) {
  
    out << "(" << type_name(tstruct, "to_") << " (T.TStruct " << name << "))";
  }
  
  /**
   * Serialize a container by writing out the header followed by
   * data and then a footer.
   */
  void t_hs_generator::generate_deserialize_container(ofstream& out, t_type* ttype, string arg) {
  
    string val = tmp("_v");
    // Declare variables, read header
    if (ttype->is_map()) {
      string key = tmp("_k");
      out << "(Map.fromList $ P.map (\\(" << key << "," << val << ") -> (";
      generate_deserialize_type(out, ((t_map*)ttype)->get_key_type(), key);
  
      out << ",";
      generate_deserialize_type(out, ((t_map*)ttype)->get_val_type(), val);
  
      out << ")) " << arg << ")";
  
    } else if (ttype->is_set()) {
      out << "(Set.fromList $ P.map (\\" << val << " -> ";
      generate_deserialize_type(out, ((t_map*)ttype)->get_key_type(), val);
      out << ") " << arg << ")";
  
    } else if (ttype->is_list()) {
      out << "(Vector.fromList $ P.map (\\" << val << " -> ";
      generate_deserialize_type(out, ((t_map*)ttype)->get_key_type(), val);
      out << ") " << arg << ")";
    }
  }
  
  /**
   * Serializes a field of any type.
   *
   * @param tfield The field to serialize
   * @param prefix Name to prepend to field name
   */
  void t_hs_generator::generate_serialize_type(ofstream& out, t_type* type, string name) {
  
    type = get_true_type(type);
    // Do nothing for void types
    if (type->is_void())
      throw "CANNOT GENERATE SERIALIZE CODE FOR void TYPE";
  
    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()) {
      if (type->is_base_type()) {
        t_base_type::t_base tbase = ((t_base_type*)type)->get_base();
        out << type_to_constructor(type) << " ";
        if (tbase == t_base_type::TYPE_STRING && !((t_base_type*)type)->is_binary()) {
          out << "$ E.encodeUtf8 ";
        }
        out << name;
  
      } else if (type->is_enum()) {
        string ename = capitalize(type->get_name());
        out << "T.TI32 $ P.fromIntegral $ P.fromEnum " << name;
      }
  
    } else {
      throw "DO NOT KNOW HOW TO SERIALIZE FIELD OF TYPE " + type->get_name();
    }
  }
  
  /**
   * Serializes all the members of a struct.
   *
   * @param tstruct The struct to serialize
   * @param prefix  String prefix to attach to all fields
   */
  void t_hs_generator::generate_serialize_struct(ofstream& out, t_struct* tstruct, string prefix) {
    out << type_name(tstruct, "from_") << " " << prefix;
  }
  
  void t_hs_generator::generate_serialize_container(ofstream& out, t_type* ttype, string prefix) {
    string k = tmp("_k");
    string v = tmp("_v");
  
    if (ttype->is_map()) {
      t_type* ktype = ((t_map*)ttype)->get_key_type();
      t_type* vtype = ((t_map*)ttype)->get_val_type();
      out << "T.TMap " << type_to_enum(ktype) << " " << type_to_enum(vtype);
      out << " $ P.map (\\(" << k << "," << v << ") -> (";
      generate_serialize_type(out, ktype, k);
      out << ", ";
      generate_serialize_type(out, vtype, v);
      out << ")) $ Map.toList " << prefix;
  
    } else if (ttype->is_set()) {
      out << "T.TSet " << type_to_enum(((t_list*)ttype)->get_elem_type());
      out << " $ P.map (\\" << v << " -> ";
      generate_serialize_type(out, ((t_list*)ttype)->get_elem_type(), v);
      out << ") $ Set.toList " << prefix;
  
    } else if (ttype->is_list()) {
      out << "T.TList " << type_to_enum(((t_list*)ttype)->get_elem_type());
      out << " $ P.map (\\" << v << " -> ";
      generate_serialize_type(out, ((t_list*)ttype)->get_elem_type(), v);
      out << ") $ Vector.toList " << prefix;
    }
  }
  
  string t_hs_generator::function_type(t_function* tfunc, bool options, bool io, bool method) {
    string result = "";
  
    const vector<t_field*>& fields = tfunc->get_arglist()->get_members();
    for (vector<t_field*>::const_iterator f_iter = fields.begin(); f_iter != fields.end(); ++f_iter) {
      if ((*f_iter)->get_req() == t_field::T_OPTIONAL
          || ((t_type*)(*f_iter)->get_type())->is_xception())
        result += "P.Maybe ";
      result += render_hs_type((*f_iter)->get_type(), options);
      result += " -> ";
    }
  
    if (fields.empty() && !method)
      result += "() -> ";
  
    if (io)
      result += "P.IO ";
  
    result += render_hs_type(tfunc->get_returntype(), io);
    return result;
  }
  
  string t_hs_generator::type_name(t_type* ttype, string function_prefix) {
    string prefix = "";
    t_program* program = ttype->get_program();
  
    if (program != NULL && program != program_)
      if (!ttype->is_service())
        prefix = capitalize(program->get_name()) + "_Types.";
  
    return prefix + function_prefix + capitalize(ttype->get_name());
  }
  
  string t_hs_generator::field_name(string tname, string fname) {
    return decapitalize(tname) + "_" + fname;
  }
  
  /**
   * Converts the parse type to a Protocol.t_type enum
   */
  string t_hs_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 "T.T_VOID";
      case t_base_type::TYPE_STRING:
        return "T.T_STRING";
      case t_base_type::TYPE_BOOL:
        return "T.T_BOOL";
      case t_base_type::TYPE_I8:
        return "T.T_BYTE";
      case t_base_type::TYPE_I16:
        return "T.T_I16";
      case t_base_type::TYPE_I32:
        return "T.T_I32";
      case t_base_type::TYPE_I64:
        return "T.T_I64";
      case t_base_type::TYPE_DOUBLE:
        return "T.T_DOUBLE";
      }
  
    } else if (type->is_enum()) {
      return "T.T_I32";
  
    } else if (type->is_struct() || type->is_xception()) {
      return "(T.T_STRUCT " + type_name((t_struct*)type, "typemap_") + ")";
  
    } else if (type->is_map()) {
      string ktype = type_to_enum(((t_map*)type)->get_key_type());
      string vtype = type_to_enum(((t_map*)type)->get_val_type());
      return "(T.T_MAP " + ktype + " " + vtype + ")";
  
    } else if (type->is_set()) {
      return "(T.T_SET " + type_to_enum(((t_list*)type)->get_elem_type()) + ")";
  
    } else if (type->is_list()) {
      return "(T.T_LIST " + type_to_enum(((t_list*)type)->get_elem_type()) + ")";
    }
  
    throw "INVALID TYPE IN type_to_enum: " + type->get_name();
  }
  
  /**
   * Converts the parse type to a default value
   */
  string t_hs_generator::type_to_default(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 "P.error \"No default value for type T_VOID\"";
      case t_base_type::TYPE_STRING:
        return "\"\"";
      case t_base_type::TYPE_BOOL:
        return "P.False";
      case t_base_type::TYPE_I8:
        return "0";
      case t_base_type::TYPE_I16:
        return "0";
      case t_base_type::TYPE_I32:
        return "0";
      case t_base_type::TYPE_I64:
        return "0";
      case t_base_type::TYPE_DOUBLE:
        return "0";
      }
  
    } else if (type->is_enum()) {
      return "(P.toEnum 0)";
  
    } else if (type->is_struct() || type->is_xception()) {
      return type_name((t_struct*)type, "default_");
  
    } else if (type->is_map()) {
      return "Map.empty";
  
    } else if (type->is_set()) {
      return "Set.empty";
  
    } else if (type->is_list()) {
      return "Vector.empty";
    }
  
    throw "INVALID TYPE IN type_to_default: " + type->get_name();
  }
  
  /**
   * Converts the parse type to an haskell type
   */
  string t_hs_generator::render_hs_type(t_type* type, bool needs_parens) {
    type = get_true_type(type);
    string type_repr;
  
    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 "()";
      case t_base_type::TYPE_STRING:
        return (((t_base_type*)type)->is_binary() ? "LBS.ByteString" : "LT.Text");
      case t_base_type::TYPE_BOOL:
        return "P.Bool";
      case t_base_type::TYPE_I8:
        return "I.Int8";
      case t_base_type::TYPE_I16:
        return "I.Int16";
      case t_base_type::TYPE_I32:
        return "I.Int32";
      case t_base_type::TYPE_I64:
        return "I.Int64";
      case t_base_type::TYPE_DOUBLE:
        return "P.Double";
      }
  
    } else if (type->is_enum()) {
      return type_name((t_enum*)type);
  
    } 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();
      type_repr = "Map.HashMap " + render_hs_type(ktype, true) + " " + render_hs_type(vtype, true);
  
    } else if (type->is_set()) {
      t_type* etype = ((t_set*)type)->get_elem_type();
      type_repr = "Set.HashSet " + render_hs_type(etype, true);
  
    } else if (type->is_list()) {
      t_type* etype = ((t_list*)type)->get_elem_type();
      type_repr = "Vector.Vector " + render_hs_type(etype, true);
  
    } else {
      throw "INVALID TYPE IN type_to_enum: " + type->get_name();
    }
  
    return needs_parens ? "(" + type_repr + ")" : type_repr;
  }
  
  /**
   * Converts the parse type to a haskell constructor
   */
  string t_hs_generator::type_to_constructor(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:
        throw "invalid type: T_VOID";
      case t_base_type::TYPE_STRING:
        return "T.TString";
      case t_base_type::TYPE_BOOL:
        return "T.TBool";
      case t_base_type::TYPE_I8:
        return "T.TByte";
      case t_base_type::TYPE_I16:
        return "T.TI16";
      case t_base_type::TYPE_I32:
        return "T.TI32";
      case t_base_type::TYPE_I64:
        return "T.TI64";
      case t_base_type::TYPE_DOUBLE:
        return "T.TDouble";
      }
  
    } else if (type->is_enum()) {
      return "T.TI32";
  
    } else if (type->is_struct() || type->is_xception()) {
      return "T.TStruct";
  
    } else if (type->is_map()) {
      return "T.TMap _ _";
  
    } else if (type->is_set()) {
      return "T.TSet _";
  
    } else if (type->is_list()) {
      return "T.TList _";
    }
    throw "INVALID TYPE IN type_to_enum: " + type->get_name();
  }
  
  THRIFT_REGISTER_GENERATOR(hs, "Haskell", "")
  