Tracking Issue for RFC 3550: New range types about rust HOT 10 OPEN

To see which iterator methods we may want to add to the new ranges, I did an informal search on
Github using the following query:

language:rust NOT is:fork /\W\s*\(\s*\w*\s*\.\.=?\s*\w*\s*\)\s*.\s*method\s*\(/

I matched on anything that looks like ( <> .. <> ) or ( <> ..= <> ) that is not immediately
preceded by some identifier character, to avoid matching things like vec.drain(..).map(_).

Example for map: search.

This isn't perfect but captures a rough amount of usage. Just looking by the number of matches:

• map: 65.8k
• rev: 23.2k
• collect: 9.9k
• for_each: 8.5k
• step_by: 8.3k
• filter: 8.2k
• flat_map: 4.2k
• fold: 3.5k
• zip: 3.4k
• filter_map: 1.6k
• find: 1.5k
• chain: 1.4k
• take_while: 1.1k
• all: 1.1k
• cycle: 0.7k
• enumerate: 0.6k
• scan: 0.4k
• product: 0.4k
• find_map: 0.3k
• any: 0.3k
• sum: 0.2k
• take: 0.2k
• skip: 0.1k
• try_*: 0.1k
• min*: 0.1k
• max*: 0.1k
• map_while: 0.1k
• position: 0.1k
• skip_while: 0.1k
• count: 0.1k
• reduce: 0.1k
• nth: 0.1k
• unzip: 0

I personally think filter is a decent cut-off, which gives the inherent methods map, rev, collect, for_each, step_by, filter.

from rust.

Any reason you left out step_by from your final list?

from rust.

@pitaj Nope, just a clerical error. I fixed it.

from rust.

another common method that was omitted: len() (idk how many instances since github gave an error when I tried the search)

from rust.

@programmerjake There is no len() on Iterator.

from rust.

@programmerjake There is no len() on Iterator.

there is on ExactSizeIterator: https://doc.rust-lang.org/std/ops/struct.Range.html#impl-ExactSizeIterator-for-Range%3Ci8%3E

from rust.

Right. I think honestly len probably makes sense regardless of whether an iterator implements it and/or how many people currently are calling it.

from rust.

I'd rather we have a better solution for len than ExactSizeIterator since, as proposed, even the new iterators for Range<u32> and RangeInclusive<i16> don't implement it.

from rust.

Ugh I forgot, there's still the problem that fn len(&self) -> usize doesn't work on ranges larger than usize, nor the 0..=usize::MAX range for usize itself.

from rust.

Let's continue that discussion about which methods to add in a separate issue here rather than on the tracking issue.

from rust.