CBOR-XS/doc/indirection.pod

=head1 REGISTRATION INFORMATION

   Tag             22098 (indirection)
   Data Item       multiple
   Semantics       hint that indicates an additional level of indirection
   Reference       http://cbor.schmorp.de/indirection
   Contact         Marc A. Lehmann <cbor@schmorp.de>

=head1 SUMMARY

This tag indicates an additional level of indirection when
decoding a value.

=head1 BACKGROUND

Data structures in some languages or data models sometimes employ
references, pointers or similar forms of indirection to represent
relationships between values. For example, in Perl, CBOR arrays are
usually represented as references to perl arrays, rather than arrays
themselves, while simple scalar values are represented as these values
themselves. However, CBOR leaves explicit references unencodable - while
arrays and maps might implicitly result in references, references to
simple values, or references to references are not representable.

For example, in Perl:

   { 1, 2, 3, 4 } # reference to a hash, becomes CBOR map
   [ 1, 2, 3, 4 } # reference to an array, becomes CBOR array
   \5             # reference to the scalar value 5, needs extension
   \[]            # reference to a reference to an array, needs extension

This tag allows to encode such references - prefixing a value with this
tag indicates a hint to the decoder that the original value was actually
a reference. Decoders can chose to heed the hint (if their data model has
a convenient representation), or simply ignore it and decode the value
as-is.

For example, CBOR encoders for Perl would not use the indirection tag for
hash and array references, as the only way to reference these values in a
data structure is already by reference. However, references to strings,
numbers, other references or other complex objects would be encoded by
tagging the referenced value with the indirection tag.

Indirection tags can be nested - each additional level of nesting would
indicate an additional indirection.

=head1 EXAMPLES

<TBD>

Revision:	1.1
Committed:	Tue Nov 26 09:43:39 2013 UTC (10 years, 7 months ago) by root
Branch:	MAIN
Log Message:	* empty log message *
#	Content
1	=head1 REGISTRATION INFORMATION
2
3	Tag 22098 (indirection)
4	Data Item multiple
5	Semantics hint that indicates an additional level of indirection
6	Reference http://cbor.schmorp.de/indirection
7	Contact Marc A. Lehmann <cbor@schmorp.de>
8
9	=head1 SUMMARY
10
11	This tag indicates an additional level of indirection when
12	decoding a value.
13
14	=head1 BACKGROUND
15
16	Data structures in some languages or data models sometimes employ
17	references, pointers or similar forms of indirection to represent
18	relationships between values. For example, in Perl, CBOR arrays are
19	usually represented as references to perl arrays, rather than arrays
20	themselves, while simple scalar values are represented as these values
21	themselves. However, CBOR leaves explicit references unencodable - while
22	arrays and maps might implicitly result in references, references to
23	simple values, or references to references are not representable.
24
25	For example, in Perl:
26
27	{ 1, 2, 3, 4 } # reference to a hash, becomes CBOR map
28	[ 1, 2, 3, 4 } # reference to an array, becomes CBOR array
29	\5 # reference to the scalar value 5, needs extension
30	\[] # reference to a reference to an array, needs extension
31
32	This tag allows to encode such references - prefixing a value with this
33	tag indicates a hint to the decoder that the original value was actually
34	a reference. Decoders can chose to heed the hint (if their data model has
35	a convenient representation), or simply ignore it and decode the value
36	as-is.
37
38	For example, CBOR encoders for Perl would not use the indirection tag for
39	hash and array references, as the only way to reference these values in a
40	data structure is already by reference. However, references to strings,
41	numbers, other references or other complex objects would be encoded by
42	tagging the referenced value with the indirection tag.
43
44	Indirection tags can be nested - each additional level of nesting would
45	indicate an additional indirection.
46
47	=head1 EXAMPLES
48
49	<TBD>
50