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Revision 26182

Date:

2009/04/10 19:26:13

Author:

lwall

Revision Log:

rename hash/pair reversal to "invert"

Files:


15	15	Moritz Lenz <moritz@faui2k3.org>
16	16	Tim Nelson <wayland@wayland.id.au>
17	17	Date: 19 Feb 2009 extracted from S29-functions.pod
18		Last Modified: 8 Apr 2009
19		Version: 4
	18	Last Modified: 10 Apr 2009
	19	Version: 5
20	20
21	21	The document is a draft.
22	22
…	…
636	636	Returns a junction which will only match against another value if none of
637	637	the keys in the hash matches.
638	638
639		=item reverse
	639	=item invert
640	640
641		our List multi method reverse ( %hash: ) is export {
	641	our List multi method invert ( %hash: ) is export {
642	642	map -> $k, $v { $v X=> $k }, %hash.kv;
643	643	}
644	644
…	…
653	653	Like hash assignment insofar as it accepts either C<Pair> objects or
654	654	alternating keys and values; however, unlike assignment, when
655	655	a duplicate key is detected, coerces the colliding entry's value to an
656		array and pushes the Pair's value onto that array. Hence to reverse
	656	array and pushes the Pair's value onto that array. Hence to invert
657	657	a hash containing duplicate values without losing (associative) information,
658	658	say:
659	659
660		%out.push(%in.reverse)
	660	%out.push(%in.invert)
661	661
662	662	Note that when reading the values of such a hash, you must not assume
663	663	that all the elements are arrays, since the first instance of a key
…	…
703	703
704	704	class Pair does Associative {...}
705	705
706		=item reverse
	706	=item invert
707	707
708		our List multi method reverse ( $pair: ) is export {
	708	our List multi method invert ( $pair: ) is export {
709	709	$pair.value X=> $pair.key
710	710	}
711	711