7863 2009-10-09 21:28:20 +0000 [XQuery 1.1] BNF of FunctionDecl allows user-defined functions to be nondeterministic 2009-10-27 16:58:04 +0000 1 1 1 Unclassified XPath / XQuery / XSLT XQuery 3.0 Working drafts PC Windows XP RESOLVED FIXED P2 normal --- 1 jim.melton jonathan.robie public-qt-comments oldest_to_newest 28181 0 jim.melton 2009-10-09 21:28:20 +0000 In the WD of XQuery 1.1 currently being prepared for internal WG review, EBNF production [31] reads: FunctionDecl ::= "declare" ("deterministic" | "nondeterministic")? ("private" | "public")? "function" QName "(" ParamList? ")" ("as" SequenceType)? (FunctionBody | "external") That syntax clearly allows: declare nondeterministic function X() external However, the 6th paragraph of Section 4.17, Function Declaration, says: An XQuery processor can use static analysis to determine whether a user-defined function is deterministic (the syntax of function declarations does not allow a user-defined function to be declared deterministic or nondterministic). (Note the typo: nondterministic.) The parenthesized statement is clearly incorrect. It states (what my memory suggests is) the intent of the WG, but it is not on its face a correct observation. Assuming that is the WG's intent, then a way must be found to make the limitation normative. Two approaches come to mind: One would rewrite the EBNF to have two alternatives, one for user-defined functions and the other for external functions. The other would have to define the limitation as a constraint, either by some sort of extra-grammatical constraint or by natural language in section 4.17. 29076 1 jonathan.robie 2009-10-27 16:58:04 +0000 In today's telcon, we agreed to add a rule to 4.17 - if a function is marked deterministic or nondeterministic, the function must be external; otherise, it is a static error.