<\> without IO

[JamieBallingall]

I was messing around trying to replace HMatrix with this library. I was hoping to see something like:

(<\>) :: MatrixType v -> v -> Maybe v

or

(<\>) :: MatrixType v -> v -> Either String v

which would allow a drop-in replacement. I thought that it was my lack of understanding of the relevant monads so I asked a question on Stack Exchange. Reading past the rather negative tone of the comments, the consensus seems to be that what I want isn't possible without changes to the library.

So I guess I'm asking for one of the following:

1. Some documentation showing how one can, in fact, suppress IO and get a Maybe
2. A fix to Use logging-effect for structured logging #20 which a comment on Stack Overflow seems to imply would help
3. A version of <\> with one of the types above

[ocramz]

Hi @JamieBallingall , thanks for getting in touch. Indeed, I agree that MonadIO constraint is unsightly and unnecessary, however the most appropriate place to discuss these interface design issues is this issue tracker and not stackoverflow. I see you filed the question on March 23 and I was completely unaware of it until now.

In fact the correct constraint on the result monad would be MonadThrow alone, of which Either e and Maybe are instances.

[JamieBallingall]

I was in the middle of typing a comment about how I'm just getting used to Github and didn't realize that this was an interface question. I guess that is illustrated by the fact that I accidentally closed the issue. Sorry about that.

[ocramz]

No worries! I'll try to address this issue soon, however I'm also in the middle of a large redesign that involves other libraries (and people) as well, so this might take a few weeks.