How to create a function accepting a closure ?

[buixor]

Hello,

I would like to know how to add a function accepting closure as an argument.

For example, I want to create a function flatten( something, { #.some_field }):

• something would be a []map[string]string
• and it would return a []string containing the some_field values found in the something array

To achieve this, I believe closure would be the best way. Is it something that can be done ? (I didn't find other examples except the builtins all/one/etc. but I don't see how to transpose this to a function I could expose).

Thanks!

[antonmedv]

You can just use this:

map(something, .some_field)

Brackets { and }, as well as # char is optional.

[buixor]

Hello,

Sorry, the flatten was just an example.

My question is really how/if I can create a function that accepts closure argument 😄

Thanks and sorry if the question was unclear

[antonmedv]

This is not possible. Those predicates (all, none, map, filter, etc) and closures are tight together. Think of them as language keywords (like for, while, do {...} while).

It may be cool to add some API to allow to use closures somehow.

What is your use case? What kind of problem you trying to solve?

[Arttii]

I was looking at the same today. My specific usecause is for a custom filter/count/sum where I want the closure to be a predicate pushdown to the left-hand side, which is a function, that does some sql queries. I was wondering what the most ergonomic way to implement this would be.

I primarily want to avoid moving data unnecessarily.