> It was somewhat surprising to me, coming from that background, that the precedence of “,” was so low, and from the other responses, it seems some others shared (or at least have been made aware of) the same confusion, although it is, as you say, easily remedied. The explanation of why the precedence is so low lies in the overloading of “,” to separate arguments in a function call, which was something where we really had no choice. This meant that we needed the concept of “ExprSingle” to mean “an expression not containing a top-level comma” to define what was allowed as a function argument, and this decision led to “,” having lower precedence than any other operator
See the original post here:
Comma problem Re: ANSWERS to "What’s wrong with
XQuery" question