Hi, Paren!

>   - Guile has no type system, so you can't express monads in terms of types

While Guile is dynamically typed, functions we define in it generally
do expect their arguments to be of certain types. And they also
generally guarantee their return values to be of certain types. So even
though there's no static type checking, it is still possible (and often
practical) to treat the functions as being typed.

Btw, I really like the explanation of a monad as function taking World
as one of its arguments and producing a modified World. Although you
probably already have your own favorite sources on the topic, here[1] is
the paper (written by someone at Microsoft, lol) where I found this
approach.

Happy dissecting,
Wojtek

[1] https://www.cs.tufts.edu/comp/150PLD/Papers/awkward.pdf


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On Wed, 25 Jan 2023 07:12:45 +0000
"(" <paren@disroot.org> wrote:

> Hello Guix,
> 
> I've been struggling to write Part 2 of Dissecting Guix; I'm just not sure where to start to
> explain monads.
> 
> It's hard for a variety of reasons, those being that:
> 
>   - Guile has no type system, so you can't express monads in terms of types
>   - Guix doesn't implement very many monads (only state, identity, and store), so it's
>     difficult to explain with a simpler monad, as there are no simpler monads
>   - Guix doesn't have functors or monoids either, so it's hard to "progressively" explain
>     first functors, then monoids, then monads
>   - Monads are just difficult in general :P
> 
> Any suggestions? :/
> 
>     -- (