Built-in function to iterate over a range of sequential numbers

[mitchgrout]

Most of the examples of creating a variable number of elements I have seen in the documentation are of this form:

for item[index] in collection : SomeElement { ... }

I would like to do something rather simple; drawing gridlines on a rectangle. The first way I think to do it would be to iterate over a range of numbers 0 ... <num-gridlines>, and using that determine my x/y ordinates for the arc. As far as I can see, there is no method like @range(min, max, step) that I could use to express this using a for.

If not already existing, would this be a valid case for its addition? For example, something like...

for _[index] in @range(10) : Path { ... } // Similar to Python's range() method

[mitchgrout]

Ah, found it noted in the Syntax > Repetition reference:

an integer, in which case the element will be repeated that amount of time

This is definitely not expected, for index in 10 immediately looks like a syntax error to me.

[tronical]

Yes, an integer can act as a model. But we could indeed also have a @range() macro, like @range(20, 40) that goes from 20..<40 for example.

[bjorn]

Just wondering, but why would this not be literally written as 20..<40 in the Slint language? It looks cleaner and clearer to me than @range(20, 40). Or is it much more complicated to implement it like that?

[mitchgrout]

My pick for @range is primarily due to it being a common method name for this pattern in other languages, and it would allow for the flexibility of a third 'step' option, like @range(x0, x1, distance-between-points)

[bjorn]

Ah, I hadn't seen it before. A least Rust, Ruby and Kotlin all feature a range expression, but yeah it does not allow specifying a step size.