Introduce operator for checking whether a collection is a subset or equal to another collection

Restrict "in" to mean just "member of" Add "hassubset" function: 1) hassubset always requires that each element of the right argument occurs at least as many times in the left argument, and that order does not matter so: hassubset( [1,2] , [1,1,2] ) => false hassubset should never take order (or gaps) into account: hassubset( [4,1,3] , [3,1] ) => true hassubset( [4,1,3] , [4,3] ) => true 2) for ordered collections, add a "hassubsequence" function that takes order into account and ignores gaps: hassubsequence( [4,1,3] , [3,1] ) => false hassubsequence( [4,1,3] , [4,3] ) => true 3) add support for ordered collections to contains (that takes gaps into account) as well as startswith, endswith, indexof, and substring.

https://tools.oasis-open.org/version-control/browse/wsvn/odata/trunk/4.01%20spec/ABNF/odata-abnf-construction-rules.txt?op=diff&rev=1047 https://tools.oasis-open.org/version-control/browse/wsvn/odata/trunk/4.01%20spec/ABNF/odata-abnf-testcases.xml?op=diff&rev=1047 https://www.oasis-open.org/committees/download.php/60941/odata-v4.01-wd02-part2-url-conventions-2017-06-07.docx