Working Draft 2005-01-18 Oren Ben-Kiki oren@ben-kiki.org Clark Evans cce+yaml@clarkevans.com Brian Ingerson ingy@ttul.org 2001-2005 Oren Ben-Kiki,  Clark Evans,  Brian Ingerson This document may be freely copied provided it is not modified. This specification is a draft reflecting consensus reached by members of the yaml-core mailing list. Any questions regarding this draft should be raised on this list.

URI: tag:yaml.org,2002:pairs Shorthand: !!pairs Kind: Sequence. Definition: Ordered sequence of key:value pairs allowing duplicates. A common type used for modeling is the ordered list of named values, allowing duplicates. For example, this is one of the basic constructs used to model XML data. YAML provides a shorthand notation for representing this data type as a sequence of one-key mappings. Most programming languages do not have a built-in native data type for supporting pairs. Such data types are usually provided by libraries. If no such data type is available, an application may resort to loading !!pairs into a native array of hash tables containing one key each. The !!pairs tag may be given explicitly. Alternatively, the application may choose to implicitly type a sequence of single-key mappings to pairs. In this case, an explicit !!seq transfer must be given to sequences of single-key mappings that do not represent pairs. # Explicitly typed pairs. Block tasks: !!pairs - meeting: with team. - meeting: with boss. - break: lunch. - meeting: with client. Flow tasks: !!pairs [ meeting: with team, meeting: with boss ]