Easy erlang model builder
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README.md

Erlang opaque types generator

This application provide parse transform for easy generate opaque Model from module it defined, with special functions.

Model description

Usage

First of all you need to enable parse_transform in module.

-module(my_model).
-compile({parse_transform, tq_record_transform}).
...

Next you need to describe fields

Fields

-field({FiledName, [{OptionName, OptionValue}]}).
...

Field name must be valid atom.

Options:

  • type
  • ext_name :: binary()
  • to_ext :: Fun | {Mod, Fun} | {Mod, Fun, Args}
  • from_ext :: Fun | {Mod, Fun} | {Mod, Fun, Args} | none
  • mode :: r | w | rw | sr | sw | srsw | rsw | srw
  • required : true | false
  • default : any()
  • default_func :: Fun | {Mod, Fun} | {Mod, Fun, Args}
  • get : true | false | custom
  • set : true | false | custom
  • record : true | false
  • validators : Fun | {Mod, Fun} | {Mod, Fun, Args}

Model

-model([{OptionName, OptionValue}]).
...

Options:

  • validators : Fun | {Mod, Fun} | {Mod, Fun, Args}

Autogenerated functions

new/0

Create new model

-spec new() -> Model.
new() -> Model.

Getters And Setters

%% Getter
-spec FiledName(Model) -> any().
FiledName(Model) -> ... .

%% Setter
-spec set_FiledName(Value :: any(), Model) -> Model.
set_FiledName(Value, Model) -> ... .

to_proplist/[1,2]

Function convert model to proplist. Only fields which access_mode marked r are stores in proplist.

-spec to_proplist(Opts, Model) -> [{atom(), any()}, ...] when
  Opts :: [Option],
  Option :: unsafe.

to_proplist(Model) ->
  ... .
to_proplist(Opts, model) ->
  ... .

Opts :

  • unsafe - put variables which access_mode marked as sr in result proplist too

to_ext_proplist/[1,2]

Same as to_proplist, but each argument transforms using to_ext field option function.

-spec to_ext_proplist(Opts, Model) -> [{atom(), any()}, ...] when
  Opts :: [Option],
  Option :: unsafe.

to_ext_proplist(Model) ->
  ... .
to_ext_proplist(Opts, model) ->
  ... .

Opts :

  • unsafe - put variables which access_mode marked as sr in result proplist too

fields/[2,3]

Same as to_proplist, but you need to specify fields, and function verifies field existanse and access mode.

-spec fields(Fields, Opts, Model) -> {ok, Proplist} | {error, Reasons} when
  Fields :: [Field],
  Field :: atom(),
  Proplist :: [{atom(), any()}, ...],
  Opts :: [Option],
  Option :: unsafe | ext_key,
  Reasons :: [{field(), Reason}],
  Reason :: unknown | forbidden.

fields(Fields, Model) ->
  ... .
fields(Fields, Opts, Model) ->
  ... .

Opts:

  • unsafe - put variables which access_mode marked as sr in result proplist too
  • ext_key - Fields are represented as binaries.
  • ignore_unknown - ignore unknown options

ext_fields/[2,3]

Same as to_ext_proplist, but you need to specify fields, and function verifies field existanse and access mode.

-spec ext_fields(Fields, Opts, Model) -> {ok, Proplist} | {error, Reasons} when
  Fields :: [Field],
  Field :: atom(),
  Proplist :: [{atom(), any()}, ...],
  Opts :: [Option],
  Option :: unsafe | ext_key,
  Reasons :: [{field(), Reason}],
  Reason :: unknown | forbidden.

ext_fields(Fields, Model) ->
  ... .
ext_fields(Fields, Opts, Model) ->
  ... .

Opts:

  • unsafe - put variables which access_mode marked as sr in result proplist too
  • ext_key - Fields are represented as binaries.

from_proplist/[1,2,3]

Generates model from proplist with atom keys.

-spec from_proplist(Proplist, Opts, Model) -> {ok, [{atom(), any()}, ...]} | {error, Reasons} when
  Proplist :: [{atom(), any()}, ...],
  Opts :: [Option],
  Option :: unsafe | ignore_unknown,
  Reasons :: [{field(), Reason}],
  Reason :: unknown.

from_proplist(Proplist) ->
  ... .
from_proplist(Proplist, Opts) ->
  ... .
from_proplist(Proplist, Model) ->
  ... .
from_proplist(Proplist, Opts, Model) ->
  ... .

from_ext_proplist/[1,2,3]

-spec from_ext_proplist(Proplist, Opts, Model) -> {ok, [{atom(), any()}, ...]} | {error, Reasons} when
  Proplist :: [{binary(), binary()}, ...],
  Opts :: [Option],
  Option :: unsafe | ignore_unknown,
  Reasons :: [{field(), Reason}],
  Reason :: unknown.

from_ext_proplist(Proplist) ->
  ... .
from_ext_proplist(Proplist, Opts) ->
  ... .
from_ext_proplist(Proplist, Model) ->
  ... .
from_ext_proplist(Proplist, Opts, Model) ->
  ... .

[ToDo] Description

field_from_ext/2

-spec field_from_ext(FieldName, Val) -> {ok, FieldVal} | {error, Reason}.

Convert value to field type using from_ext function and valid result value with field validators.

[ToDo] Description

valid

-spec valid(Model) -> ok | {error, Reasons}.

Check that model is valid, by performing each field validator and whole model validators.

get_changed_fields/1

-spec get_changed_fields(Model) -> [{FieldName, FieldValue}, ...].

Return the list that was changed.

is_new/1

-spec is_new(Model) -> true | false.

Return true if model is new. Uses at most with db model generators.

is_changed/2

-spec is_changed(FieldName, Model) -> true | false.

Check that field is changed.

get_field_name/2

-spec get_field_name(FieldName, Opts) -> {ok, ModelFieldName} | {error, Reason} when
    FieldName :: binary() | atom(),
    Opts :: [Opt],
    Opt :: ext_key | {mode, Mode},
    Mode :: r | w | rw | sr | sw | srw | rsw | rsrw,
    Reason :: {FieldName, unknown} | [{any(), unknown_option}].

Check that field exists in model structure and accessable with 'mode' rights. Field name must be binary if ext_key option is set.

Example

user.erl

-module(user_model).
-compile({parse_transform, tq_record_transform}).

-field({name,
  [required,
   {type, binary},
   {mode, rw}
  ]}).

-field({age,
  [required,
   {type, integer},
   {mode, rw},
   {validators, [{more_then, [18]}]}
  ]}).

-field({password,
  [{type, binary},
   {mode, srw}
  ]}).

more_then(A, Val) when A > Val ->
  {error, {less_then, A}}.
more_then(A, _Val) ->
  ok.

Usage:

1> Data = [{<<"name">>, <<"User1">>}, {<<"password">>, <<"123456">>}, {<<"unknown_data">>, <<"qwerty">>}].
2> {ok, User} = user_model:from_ext_proplist(Data, [ignore_unknown]).
3> User:valid().
{error, [{age, required}]}
4> User2 = User:set_age(12).
5> User2:valid().
{error, [{age, {less_then, 18}}]}
6> User3 = User2:set_age(20).
7> User3:valid().
ok
8> User3:to_proplist().
[{age,20},{name,<<"User1">>}]
9> User3:to_proplist([unsafe]).
[{password,<<"123456">>},{age,20},{name,<<"User1">>}]