Embedded RValue Function Call Syntax

Anywhere where a normal RValue can be accepted we would like to allow an additional syntax for functional calls. The motivation is remove the need for %Response:...% which can't do proper XPath escaping if using an embedded {} segment. Replacing the parse engine to do escaping is considered too difficult and will have a serious performance impact (theorized on how it works).

A parenthetical expression would server our purposes:

set %Value% (function param1 ... paramN)

This would also leave room for the numeric expressions (though not part of this request), in the form of:

 (= expr )

This is considered to be minimally backwards incompatible (only values starting with a parenthesis would be affected. An escaped parenthesis is then needed to address these situations. Detected this incompatibly should be easy, you'll get a parsing error as it won't recognize some random text as a function.