Concerning monad patterns, I was thinking of expressions like these:
do SomeEvent a <- streamOfEvents
...
Depending on the stream monad involved (including []), this can have the
desired semantics.
On Mon, 13 Jul 2015 21:01:54 +0300, Nikolay Amiantov
Ouch, I feel deeply ashamed for not thinking of that from the beginning! While not being a general solution "Pattern a -> a -> Bool" this covers almost all my use cases (with rest of processing, too) while requiring no extensions, no dependencies and overall being readable and "boring" in Sven's sense (at least I feel so -- comprehensions are being taught in every Haskell tutorial under the sun and are pretty self-describing). It remains a question of whether it's equally readable in monadic case ("huh? list comprehension? but... this is a Maybe/an Event!"), but in most my GUI/event-processing code I use lens anyway to cope with deep hierarchies of records describing events, so it's not much of a problem there. Thanks!
On 07/13/2015 08:03 PM, Niklas Haas wrote:
For this specific use case, you can also consider list comprehensions:
[ x | x@(DataDefinition _) <- tlds ]
I personally greatly prefer this over something like ‘filter’ + an ugly lambda, especially if you can use the list comprehension for the rest of your processing as well. -- Nikolay.