Actually numbers are allowed, but not all numbers. If you look at http://docs.racket-lang.org/xml/index.html?q=xexpression#(def._((lib._xml/main..rkt)._valid-char~3f))
It tells you which numbers are allowed, and 2 is not. I'll change the error message to say "valid numeric entity" rather than "number". Jay On Tue, Feb 28, 2012 at 2:13 AM, Jens Axel Søgaard <jensa...@soegaard.net>wrote: > 2012/2/28 Johannes Brauer <bra...@nordakademie.de> > >> Hi! >> >> In DrRacket version 5.02 this x-expression >> >> (validate-xexpr '(add x 2)) >> >> is legal. In version 5.2 I get the error message >> >> Expected a string, symbol, number, comment, processing instruction, or >> list, given 2 >> >> Can anyone explain this to me? >> > > According to the grammar in the documentation a lone number is not an > x-expression. Use '(add x "2") instead. > > xexpr = string | > (list<http://docs.racket-lang.org/reference/pairs.html?q=xexpression#%28def._%28%28quote._%7E23%7E25kernel%29._list%29%29> > symbol > (list<http://docs.racket-lang.org/reference/pairs.html?q=xexpression#%28def._%28%28quote._%7E23%7E25kernel%29._list%29%29> > > (list<http://docs.racket-lang.org/reference/pairs.html?q=xexpression#%28def._%28%28quote._%7E23%7E25kernel%29._list%29%29> > symbol string) ...) xexpr ...) | > (cons<http://docs.racket-lang.org/reference/pairs.html?q=xexpression#%28def._%28%28quote._%7E23%7E25kernel%29._cons%29%29> > symbol > (list<http://docs.racket-lang.org/reference/pairs.html?q=xexpression#%28def._%28%28quote._%7E23%7E25kernel%29._list%29%29> > xexpr ...)) | symbol | > valid-char?<http://docs.racket-lang.org/xml/index.html?q=xexpression#%28def._%28%28lib._xml/main..rkt%29._valid-char%7E3f%29%29> > | cdata | misc > > -- > Jens Axel Søgaard > > > ____________________ > Racket Users list: > http://lists.racket-lang.org/users > > -- Jay McCarthy <j...@cs.byu.edu> Assistant Professor / Brigham Young University http://faculty.cs.byu.edu/~jay "The glory of God is Intelligence" - D&C 93
____________________ Racket Users list: http://lists.racket-lang.org/users
