Re: Flattening out arguments to splice

#!/usr/bin/perl

use 5.14.0;
use strict;
use warnings;

sub my_splice_like_func
{
    my ($list, $offset, $length) = @_;
    my @copy = @$list;
    return splice @copy, $offset // 0, $length // @copy - $offset;
}

$, = ' ';                               # just keepin' it pretty

my $list = [qw< one two three four >];
say my_splice_like_func($list, 2);      # want "three four"; get "two 
+three four"
say my_splice_like_func($list, 2, -1);  # want "three"; get "three fou
+r"
[download]

Comment on Re: Flattening out arguments to splice Download Code

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Re^2: Flattening out arguments to splice by jwkrahn (Abbot) on May 30, 2018 at 00:34 UTC
splice ARRAY,OFFSET,LENGTH,LIST You forgot the fourth argument: 'LIST'. `my ($list, $offset, $length, @list) = @_;` [download]	[reply] [d/l]
Re^3: Flattening out arguments to splice by AnomalousMonk (Archbishop) on May 30, 2018 at 02:39 UTC
New splicer function operates on external referent (although I'm not sure what this gets you: it's almost exactly like splice) (update: needs Perl 5.10+ for // operator): c:\@Work\Perl\monks>perl -wMstrict -MData::Dump -le "use 5.010; ;; sub my_splicer { my ($ar, $offset, $len, @list) = @_; $offset //= 0; $len //= @$ar - $offset; return splice @$ar, $offset, $len, @list; } ;; use constant TEST => qw(one two three four five six seven eight); ;; my $ar; my @spl; my @args; ;; $ar = [ TEST ]; @args = (); @spl = my_splicer($ar, @args); dd \@spl, $ar; ;; $ar = [ TEST ]; @args = (2); @spl = my_splicer($ar, @args); dd \@spl, $ar; ;; $ar = [ TEST ]; @args = (2, 3); @spl = my_splicer($ar, @args); dd \@spl, $ar; ;; $ar = [ TEST ]; @args = (2, 3, qw(FOO BAR)); @spl = my_splicer($ar, @args); dd \@spl, $ar; " ( ["one", "two", "three", "four", "five", "six", "seven", "eight"], [], ) ( ["three", "four", "five", "six", "seven", "eight"], ["one", "two"], ) ( ["three", "four", "five"], ["one", "two", "six", "seven", "eight"], ) ( ["three", "four", "five"], ["one", "two", "FOO", "BAR", "six", "seven", "eight"], ) [download] Update: Note this code will also work as expected with something like `@args = ($ar, 2, 3, qw(FOO BAR));` `@spl = my_splicer(@args);` Give a man a fish: `<%-{-{-{-<`	[reply] [d/l] [select]
Re^3: Flattening out arguments to splice by AnomalousMonk (Archbishop) on May 30, 2018 at 01:58 UTC
I haven't tested this, but I believe that in tybalt89's code (and in your OP code), because the splice is operating on a copy of the `$list` array reference argument, so a fourth argument `LIST` would be assigned to the lexical array `@copy` and then almost immediately lost along with that array. Do you mean that you want your function to operate on the external referent of the `$list` array reference? Give a man a fish: `<%-{-{-{-<`	[reply] [d/l] [select]