Comment by hnedeotes

I agree with the no silver bullet thing - and written on another reply I don't even know if I agree with the example in the article.

> The fact that a map() function tells you that you're converting elements of lists does not save you from understanding what is that conversion doing and why.

It can actually, say you have a query that comes in, this calls a function that fetches records from the database, it's not a basic query, it has joins, perhaps a subquery, etc. Then you have another function that transforms the results into whatever presentational format, decorates, wtv, those results, and it's also more than a few basic couple lines of logic.

And now you have a bug report come in, that not all expected results are being shown.

If you have

  func does_query -> loop transforms

You have 3 possibilities, the problem is on the storage layer, the problem is on the query, the problem is on the loop. You read the query, because the bug is subtle, it seems ok, so now you move to the loop. It's a bit complex but seems to be correct too. Now you start debugging what's happening.

If you have

  func does_query -> func maps_results

You know it's either underlying storage or the query. Since the probability of the storage being broken is less plausible, you know it must be the query. In the end it's a synch problem with something else, and everything is right, but now you only spent time on reproducing the query and being sure that it works as expected.