generic-data-functions

A small Haskell library providing some funky generics that work over arbitrary Haskell data types. We handle the sums of products representation; you only need to pass a handful of definitions. Obtain simple, type-safe generic serializers/reducers and parsers for almost zero effort.

Functions

foldMap (L->R)

foldMap :: (Foldable t, Monoid m) => (a -> m) -> t a -> m

The user provides the a -> m dictionary via a special type class instance. Constructor fields are mapped and combined left-to-right. Sum representations are handled by mappending the constructor via a user-supplied String -> m first.

Useful for:

• simple binary serializers which just concatenate fields together
• reducing to a numeric value

traverse (L->R)

traverse :: (Traversable t, Applicative f) => (a -> f b) -> t a -> f (t b)

The user provides the f a dictionary via a special type class instance. Constructor field actions are run left-to-right. Sum representations are handled by running a constructor action first (thus requiring Monad f).

Useful for:

• simple binary parsers which can parse generic foldMap output

Notes

Orphan instances

This library is designed to work with and around existing libraries and type classes. Thus, you will likely be dealing in orphans. Instances, that is. That's life, Jim.

License

Provided under the MIT license. See LICENSE for license text.

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senserial is a small library providing reusable generics for (binary) parsers and serializers. No need to muddle through boilerplate generics that look the same as everyone else's; just provide a few definitions and senserial can give you powerful generic instances.

Currently an unofficial library, distributed as part of binrep. Reader, please let the author know if you'd like it released separately.

Why?

It is 2023. There are a number of competing parsing and serialization Haskell libraries, and some notable high-performance binary serialization libraries. These are often fairly experimental. Maybe you want some generics to benchmark some real-world use case against popular libraries like binary and cereal. But maybe generics aren't provided. Shucks.

That's a shame, because a pure generic binary parser or serializer doesn't have much work to do:

• traverse the generic sum-of-products tree of the given type left to right
• defer to the appropriate type class for base cases

Sum types necessitate a little more work. Otherwise, most generic binary parsers and serializers look fairly comparable to each other. Why are we rewriting this stuff over and over again?

senserial provides reusable generics which have holes in for your favourite parsers and serializers. Fill out a few definitions to receive a fresh new generic instance for your own library, without all the boilerplate.

Really?

Kind of. In reality, this library can only handle cases where no configuration is needed other than what is provided in the data type itself. senserial provides the generic traversal, and you can't alter that. Plus, the only often rewritten and straightforward traversal I can think of is sequential field concatenation. So though the code isn't limited to bytestrings and binary serialization formats, you will have trouble using it for anything else, because anything else will probably require a very different traversal (e.g. JSON serialization).

In short, the primary use of this library is to pull out the common generics patterns from binary serialization libraries for easy reuse.