Relude does not currently support compiling with native ReasonML/OCaml (i.e. via esy nor dune). There is an issue open to track progress.
The way that npm installs dependencies was designed specifically for the JavaScript ecosystem,
where it made sense for each library to install its own set of dependencies. That way, each dependency could be installed with some level of confidence that it would work with its own set of dependencies, and not be affected by other libraries installing other likely incompatible versions of the same dependencies.
However, in a statically-typed language, this doesn't work so well, because the compiler seeks to align the shared types across modules and libraries. E.g. if two libraries A and B depend on some module C, the compiler will expect to find a single version of the library C, so that it can compile A and B with the same types exposed by C. If this were not the case, it would be difficult for libraries to work together with the same shared types.
We use peer dependencies in all Relude libraries, so that the top-level host library or application can ultimately control what single version of each dependency is installed. E.g. Relude depends on bs-bastet as a peer dependency, so any library using Relude must also explicitly install bs-bastet, as it won't be installed automatically with Relude.
What's the difference between Relude.Result and Belt.Result, Relude.Option and OCaml stdlib option, Relude.Js.Json and Js.Json, etc.?
Relude has many modules that augment existing types from Belt or the OCaml standard library, which are both available by default within Melange/ReasonML projects. Sometimes we alias the types from Belt or the OCaml stdlib, and sometimes our corresponding modules simply add additional functions for these common types.
Relude also has many of its own types, which have their own modules, like Relude.AsyncResult, Relude.ReaderT, etc.
I'm getting strange errors about types like array(string) not being the same as BsBastet.Array.Foldable.t
If you are trying to compile and get an error like:
This has type array(t) but somewhere wanted BsBastet.Array.Foldable.t(string)`
you likely need to add bs-bastet to your bs-dependencies in your bsconfig.json file. This error occurs because Melange is not able to find the types defined in the BsBastet module, so it can't determine that array(t) is the same type as BsBastet.Array.Foldable.t(string).
Because we are not using .rei interface files, we are not able to abstract these types away for functions that get included into our implementation modules. (See .rei topic below).
Relude relies heavily on the module include capability of ReasonML/OCaml. Many of the typeclasses in Relude have extension modules that can be include'd into your module to add a variety of useful utility functions, operators, and extension modules to your host module "for free," simply because you've taken the time to create an instance of a given typeclass. Because there are lots of functions automatically added to many modules, it becomes difficult to maintain good .rei files which expose all of these automatically added functions, while at the same time including documentation and more specialized type annotations. Until we have a maintainable solution for this challenge, we are avoiding the use of .rei files.