Re: Generating type specs programmatically

Hello Olivier,

On Mon, 7 Dec 2020 at 08:34, Olivier Boudeville <
[email protected]> wrote:

> Hi Guilherme,
>
> I may understand incorrectly your question, but type specs are
> well-defined in ASTs and stored appropriately in them (see
> https://erlang.org/doc/apps/erts/absform.html for a mostly accurately
> view of the AST grammar), so they can be freely read from there and written
> there as well, either directly (as raw terms) or through appropriate,
> "standard" Erlang API functions.
>

Ahh, true! I encountered that document a few years ago - but I had
forgotten about it entirely.


>
> (I preferred the former method and apparently it works satisfactorily, for
> example it is used in
> https://github.com/Olivier-Boudeville/Ceylan-WOOPER/blob/712bcc587e73f2da1529b175dfb1d458be36e983/src/wooper_instance_construction.erl#L308
> ; I suppose the AST structure is not likely to change a lot anytime soon,
> and, should this happen, then it will be just a matter of updating
> accordingly the generation logic; I found it clearer to generate forms
> through terms rather than thanks an abstracting API)
>

Indeed, I now remember generating specs like this in the past. Thanks!



>
> Hope this helps,
>
> Olivier.
>
>
>
> Le 12/7/20 à 12:52 AM, Leonard B a écrit :
>
> Hi Guilherme,
>
> I may be wrong, but I'm pretty sure specs are just syntactic sugar for
> dialyzer (and devs) and are not actually included in the AST. Just sounds
> like you may be looking for something that's not there.
>
> Kind regards,
> Leonard
>
> On Sun, Dec 6, 2020, 14:13 Guilherme Andrade <[email protected]> wrote:
>
>> Thanks for the suggestion!
>>
>> After a quick glance, Typer seems to be directly generating string
>> representations of the specs - that is, not actually manipulating the AST
>> of the modules it works on by inserting nodes that represent said specs.
>>
>> That's a shame, but it's what I will also do if I don't find a more
>> elegant way to do it through `erl_syntax`.
>>
>> Oh well.
>>
>> On Sat, 5 Dec 2020 at 22:29, Fred Hebert <[email protected]> wrote:
>>
>>> You might want to look at Typer, since it's whole purpose is to generate
>>> type specs for code that you can directly put in code.
>>>
>>> On Sat, Dec 5, 2020 at 3:25 PM Guilherme Andrade <[email protected]> wrote:
>>>
>>>> Hello list,
>>>>
>>>> I've been working on a code-generating tool, leveraging `erl_syntax`[1]
>>>> to build an AST containing arbitrary Erlang functions; I then use
>>>> `erl_pp`[2] to generate the corresponding Erlang code and write the result
>>>> onto a source code file.
>>>>
>>>> All is well so far, but now I want to generate type specs and function
>>>> specs with which to annotate the generated code - and I can't for the life
>>>> of me figure out how to do it within `erl_syntax`.
>>>>
>>>> All of the different attempts I've made end up either crashing within
>>>> `erl_syntax` or `erl_pp`, or at best result in INVALID-FORM literals within
>>>> the generated code.
>>>>
>>>> Would any of you be able to point me in the right direction?
>>>>
>>>> Thanks in advance!
>>>>
>>>> [1]: http://erlang.org/doc/man/erl_syntax.html
>>>> [2]: https://erlang.org/doc/man/erl_pp.html
>>>>
>>>> --
>>>> Guilherme
>>>>
>>>
>>
>> --
>> Guilherme
>>
>
> --
> Olivier Boudeville
>
>

-- 
Guilherme