The matchesPattern function returns true if the second parameter string value evaluates to a [ECMAScript] (JavaScript) regular expression and the result of the first argument string matches that regular expression, using syntax and semantics of [ECMAScript] regular expressions, otherwise it returns false.
Add matchesPattern as a $filter function:
Edm.Boolean matchesPattern(Edm.String,Edm.String)
The matchesPattern function returns true if the second parameter string value evaluates to a [ECMAScript] (JavaScript) regular expression and the result of the first argument string matches that regular expression, using syntax and semantics of [ECMAScript] regular expressions, otherwise it returns false.