Haskell Weekly

What Template Haskell gets wrong and Racket gets right

Why are macros in Haskell terrible, but macros in Racket great?

Optionally Exposed

A build tool giving me a transitive dependency on text only so that the instance you defined compiles is pointless.

Algebraic patterns: Semigroup

A Semigroup is a data type together with a method of composition satisfying the associativity rule.

Rank ’n Classy Limited Effects

Applications, then, are just an environment comonad of monad morphisms. More plainly, they’re a record of effect interpreters.

Destroy All Ifs: A Perspective from Functional Programming

By replacing conditionals with lambdas, we can invert control and make our code both easier to reason about and more generic.

Typeclasses and Run-Time Dependency Management

But what we need is a run-time error, not a compile-time one. (This is one of the rare cases you’ll hear a Haskeller saying this.)