Morning!

Moin moin...

Morning

o/

guys, what's the preferred method of running a side-effecting function over a (potentially lazy) collection of items?

(mapv, doall, dorun, ...?)

I use doseq personally

has for like semantics

run! is also good

😄

What bronsa said. run! is specifically meant for this… doseq, dorun, mapv and others have slightly different purposes. run! is specifically meant for where you have a side effecting function that you want to apply to each thing in the collection.

to be fair doseq/`dorun` are also specifically meant for side-effecting over collections

you could argue that doall isn't specifically about that, but the docstring also explicitely mentions side-effecty stuff

>to be fair doseq/`dorun` are also specifically meant for side-effecting over collections Absolutely. My point is really that run! is really meant for when you have a side effecting procedure of the right shape already; which is (nearly) what @lady3janepl asked for i.e. (run! println coll) is arguably better than (doseq [v coll] (println v)). Though if you’re not breaking the side effect out into a procedure you can use doseq… there’s lots of subtlety around picking the right one here — most of which is arguably also splitting hairs. Though you might prefer doseq if you needed to apply other args too.

run! came after doseq and dorun I guess doseq breaks composability because it is a macro which may have been one of the usecases for adding run!

We ended up using run! all over the place. Much tidier than doseq/`dorun` most of the time, as long as you don't care about anything apart from the side effect.

yeah run! was added in 1.7

doseq etc were pre 1.0

Nice, thanks. I didn’t know about run!

I’ve got a list of elements being converted and then saved as separate files, so I don’t need the result, and I don’t care about their order