Forbid multiple VERSION occurences?

[Tpt]

Currently the SPARQL 1.2 grammar allows multiple VERSION "..." statements. Does it make sense to keep this or should we restrict the grammar to contain a single VERSION?

We don't support the concatenation use case in SPARQL so I don't see much value of allowing multiple occurrences.

Also, again because we don't care about concatenations, should we mandate VERSION to occur before PREFIX and BASE? It might be handy if in the future version we change PREFIX or BASE behaviors.

[afs]

You mean this change?

Prologue	  ::=  	( BaseDecl | PrefixDecl | VersionDecl )*

==>

Prologue	  ::=  	VersionDecl? ( BaseDecl | PrefixDecl )*

Note effect on SPARQL Update.

[afs]

This is related to Turtle. Turtle is more prone to concatenating fragments.

https://www.w3.org/TR/rdf12-turtle/#sec-grammar-grammar

Currently, prefixes, base and version can be between any (triples production.

Turtle suggests, in a note, placing VERSION "early in the document".