@dodgez/ts-monads

ts-monads

This package provides monads based on my (limited) experience with Haskell and has a lot of issues and incomplete functionality.

There are currently two monads provided for use in Typescript:

1. The IO monad wraps input/output operations similar to Haskell
2. The Maybe monad (and type!) provides an interface for maybe types

Note: IO commands are only meant to be used as arguments to a top-level function call of io_main.

Commands

• Compile the package, run npm run build
• Run unit tests, run npm test
• Run an example, run ts-node examples/{io,monad}.example.ts

Examples

• examples/io.example.ts an example that prints package.json without "extra" whitespace.
• examples/maybe.example.ts an example of a safe list.head and division function.

Drawbacks

The (>>=) and (>>) operators are not valid identifiers, and TypeScript doesn't support infix operators, so the following are replacements:

• >>= is replaced with $$_ and is called on the left object. E.g. IO.return(3).$$_(io_log)
• >> is replaced with $$ and is called on the left object. E.g. io_log("Hello").$$(io_log("World!"))

Since TypeScript does not natively support macros, do syntax is not supported thus every Monad chain needs to be written manually.