How to collect "some" items of a range in an array?

[Dukc]

On Monday, 6 January 2025 at 19:30:27 UTC, Renato wrote:
> My use case is to parse a file format where a line is expected 
> to have 4 items. I am currently using `takeExactly(4)` but that 
> doesn't let me index on it.

I suspect you might unknowingly be the victim of autodecoding. If 
your line is a string, ergo an array of immutable `char`s (or a 
`wstring`), Phobos functions will treat that as a range of 
`dchar`s. Since reading four Unicode code points (`dchar`s) might 
potentially consume more than four UTF-8 code points (`char`s) 
from the line, the result of `takeExactly` can't be random access.

You could use 
[`.byCodeUnit`](https://dlang.org/phobos/std_utf.html#byCodeUnit) 
on your line before giving it to `takeExactly`. I think 
`takeExactly` is random access if it's source range is. However, 
be aware that this will split any non-ASCII Unicode symbol in the 
line to multiple characters, all invalid by themselves. It 
depends on your use case whether this matters or not. If it does, 
the `staticArray` solution earlier in this thread is probably 
what you want instead.