TsAccess - Getters/Setters generator for TypedStruct


recently I started using TypedStruct and also for quite some time I have problem with typos when using structs in elixir, mainly that struct.fiewld_name is not reported during compile time. So I was playing with idea to create plugin for TypedStruct that would generate getter and setter functions for struct. Good thing is, that when I do typo in function name, code don’t compile, another good thing is that it also generate typespecs, so I assume that dialyzer should report when I try to pass wrong type to setter (untested). I used @before_compile and module attributes that TypedStruct is adding to module:


defmodule Example do
  @before_compile TsAccess
  use TypedStruct

  typedstruct do
    field(:name, :string)

iex> Example.name(%Example{}, "John Doe")
%Example{name: "John Doe"}

iex> Example.name(%Example{name: "John Doe"})
"John Doe"

I’m also thinking to do another library (or as another feature to this one) that would generate lenses

What do you think?


Will these throw an error if given a map?

Will these preserve the struct type when setting a value?

If so seems great!

  1. Yes (it did not, but great idea so I added it :D)

  2. Yes

Thank you for feedback

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Since it is mi first try at doing library for elixir, CR and API critique is welcomed :slight_smile:

Exceptional! Thanks, this is awesome!

Hello again, I just published version 0.5.0 in which typedstruct is not neceseary anymore and also explicit mode was added where you can define getters explicitly:

defmodule Example do
  use TsAccess, explicit: true
  defstruct [

  defaccessor :accessible
  defgetter :gettable

  defsetter :settable

All macros support also setting of attribute type:

defsetter :name, String.t()

In case of nonexplicit mode without typed struct, types for specs can by set using @types module attribute:

defmodule Example do
  use TsAccess

  @types [
    name: String.t()
  defstruct [

Hope someone find this usable :slight_smile:
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0.6.0 I also added lenses generator (base on elixir Access module) generated functions looks like:

get_in(example, [Example.name_lens()])
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After some sleep I realized that I don’t need postfix _lens, so now lenses are just field functions without arguments a.k.a get_in(example, [Example.name]) function with postfix _lens are generated with deprecation warning. Also any other ideas how further improve it? I have several:

  • in implicit mode add exclude, only to using
  • add prefix, postfix or callback to generate function names
  • explicit deflens, but this is little bit complicated since I don’t know how to check if field exists
  • add alias option to defsetter, defgetter and defaccesor
  • add onli, exclud, onli to defaccessor (in case of explicit lens, to choose what should by generated)

Feedback is welcomed :slight_smile:

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Ooo I really like how you setup the lenses!

1 Like