ulysses4ever
commented
4 days ago Hello!
Disclaimer. This is an experimental library. It's also not under active development these days.
That said, the library has basic stuff working. In particular, (well-formed) @mdo expressions return monadic values. One particular example of a monadic value is nothing, and this value can appear as a result of an @mdo expression in the Maybe monad. The doc page you reference has such an example with nothing as a result. But the same doc page has several examples with results other than nothing. For example, the very first example returns a list (a value of type MList in this case)
julia> @mdo MList begin
a <- MList(1:3)
b <- MList(1:3)
guard(a!=b)
return (a,b)
end
MList([(1,2), (1,3), (2,1), (2,3), (3,1), (3,2)])What led you to believe @mdo always returns nothing? Can you provide a specific example?
Hi, I am fairly new to julia but got quite excited when I found out that there is a Monads library. Now even with all the tests passing I am uncertain if the mdo macro works properly. I was going through the examples on https://monads-jl.readthedocs.io/en/latest/ but had to find out, that all the code snippets including the mdo macro does indeed return nothing!