Rewrote some erlang glue code and made use of some header files and records

[Magd74NA]

Added a header file to represent simplifile's file_info type and rewrote the file type checking functions to take advantage of it.

[Magd74NA]

Hi! This is my first Github contribution ever and my work in Gleam and Erlang ever! I was reading the source code for simplifile to learn some Gleam and specifically about how the FFI to Erlang works which lead me to reading the Erlang file documentation and realizing there are some slightly nicer coding patterns (I think?) that could be used on the Erlang side by writing header files.

[bcpeinhardt]

Howdy! Thanks for making this PR!

I'm not exactly a pro erlanger either, so take my feedback with a grain of salt :)

I'm not overly fond of the check_file_type helper function, as I think it makes the control flow less clear to avoid a relatively small amount of boilerplate. Wherever possibly I want the ffi to be simple and shallow.

I'm also not a big fan of the introduction of the simplifile_file_info record type. I think it would probably be a great idea if we were just writing Erlang, but we already define the type it's representing in Gleam as the FileInfo type, and I'd prefer to have a single source of truth for the type's structure to avoid accidental drift.

I very much like the refactoring of file_info_result to take advantage of record syntax. Perhaps we could also add a comment linking to the file_info record's definition: https://www.erlang.org/doc/apps/kernel/file.html#t:file_info/0.

This is really good stuff for a first time with Gleam and Erlang 😎 I'm not sure simplifile is the best library to contribute to for the purpose of learning gleam, as it is heavily ffi based. That said the contribution is still very much welcome :)

[Magd74NA]

Howdy! Thanks for making this PR!

I'm not exactly a pro erlanger either, so take my feedback with a grain of salt :)

I'm not overly fond of the check_file_type helper function, as I think it makes the control flow less clear to avoid a relatively small amount of boilerplate. Wherever possibly I want the ffi to be simple and shallow.

I'm also not a big fan of the introduction of the simplifile_file_info record type. I think it would probably be a great idea if we were just writing Erlang, but we already define the type it's representing in Gleam as the FileInfo type, and I'd prefer to have a single source of truth for the type's structure to avoid accidental drift.

I very much like the refactoring of file_info_result to take advantage of record syntax. Perhaps we could also add a comment linking to the file_info record's definition: https://www.erlang.org/doc/apps/kernel/file.html#t:file_info/0.

This is really good stuff for a first time with Gleam and Erlang 😎 I'm not sure simplifile is the best library to contribute to for the purpose of learning gleam, as it is heavily ffi based. That said the contribution is still very much welcome :)

Thank you very much for the feedback! I'm interested in the whole BEAM ecosystem in general really. Also I did specifically want to understand how to write FFI in Gleam. Gleam just seems like the cleanest and simplest to actually write things in. I've never done FP before so I'm still trying to wrap my head around everything involved. I found myself using the library a lot for my small practice projects so I wanted to understand it a bit better! I will update my PR with your suggestions.

[Magd74NA]

I just amended my PR with the changes you suggested.