From @masak

<colomon> does this imply we should have (for instance) first-rw,
which returns the container of the first value that smartmatches?
<colomon> or perhaps more interestingly, grep-rw?
<pmichaud> I think that .first perhaps ought to be "is rw"
<pmichaud> grep is already rw-like, or should be.
<pmichaud> grep returns the elements maching a criteria, not just the
values matching a criteria
<colomon> r​: my @​a = 1..10; @​a.grep(* %% 2).>>++; say @​a
<camelia> rakudo 8a76ba​: OUTPUT«1 3 3 5 5 7 7 9 9 11␤»
* colomon 's head explodes
<masak> if .grep works like that, surely .first should as well :)
<masak> r​: my @​a = 1..10; @​a.first(* %% 2).>>++; say @​a
<camelia> rakudo 8a76ba​: OUTPUT«Cannot modify an immutable [BLA BLA BLA]
* masak submits rakudobug
<pmichaud> note that grep works like that in p5 as well
* colomon is split between one side that says "THAT'S AWESOME!" and
another that says "That's a grotesque distortion of what should be a
nice functional method."
<pmichaud> in some sense, it *is* a functional method in this form.
It's returning exactly the elements that matched (the containers),
without imposing a decontainerize operation on them
<pmichaud> if you decontainerize, you're not getting the elements that
matched, you're getting the values of the elements that matched.

@coke - Status changed from 'new' to 'open'

From @coke

On Thu Jul 04 09​:28​:09 2013, masak wrote​:

<colomon> does this imply we should have (for instance) first-rw,
which returns the container of the first value that smartmatches?
<colomon> or perhaps more interestingly, grep-rw?
<pmichaud> I think that .first perhaps ought to be "is rw"
<pmichaud> grep is already rw-like, or should be.
<pmichaud> grep returns the elements maching a criteria, not just the
values matching a criteria
<colomon> r​: my @​a = 1..10; @​a.grep(* %% 2).>>++; say @​a
<camelia> rakudo 8a76ba​: OUTPUT«1 3 3 5 5 7 7 9 9 11␤»
* colomon 's head explodes
<masak> if .grep works like that, surely .first should as well :)
<masak> r​: my @​a = 1..10; @​a.first(* %% 2).>>++; say @​a
<camelia> rakudo 8a76ba​: OUTPUT«Cannot modify an immutable [BLA BLA BLA]
* masak submits rakudobug
<pmichaud> note that grep works like that in p5 as well
* colomon is split between one side that says "THAT'S AWESOME!" and
another that says "That's a grotesque distortion of what should be a
nice functional method."
<pmichaud> in some sense, it *is* a functional method in this form.
It's returning exactly the elements that matched (the containers),
without imposing a decontainerize operation on them
<pmichaud> if you decontainerize, you're not getting the elements that
matched, you're getting the values of the elements that matched.

13​:17 <+dalek> rakudo/nom​: 07ef21e | duff++ | src/core/Any.pm​:
13​:17 <+dalek> rakudo/nom​: Fixes RT #​118755
13​:17 <+dalek> rakudo/nom​: review​:
  rakudo/rakudo@07ef21ed55

Closable with tests?

--
Will "Coke" Coleda

From @usev6

This works now​:

$ perl6-m -e 'my @​a = 1..10; @​a.first(* %% 2).++; say @​a'
1 3 3 4 5 6 7 8 9 10

I added a test for this (and for the example with grep) to S32-list/first.t and S32-list/grep.t, respectively, with the following commit​: Raku/roast@4295bfcfae

@usev6 - Status changed from 'open' to 'resolved'