2010-10-12 17:33:40: Created issue 'Require whitespace around binary "+" and "-" inside calc()' nickname owned by Bert Bos on product CSS3 Values and Units, description 'David wrote in
that there should be required spaces on both sides of binary operators "+' and "-".
It avoids confusion over why 'calc(3em+2px)' works but 'calc(3em-2px)' doesn't.
This may already have been in a previous draft, but it is not in the editor's draft of August 2010.
If accepted, the change would be to replace
sum : product [ [ "+" | "-" ] S* product ]*;
sum : product [ S [ "+" | "-" ] S+ product ]*;
(That gives a grammar that requires lookahead, so some more rewriting is needed if that is not acceptable.)' non-public [Bert Bos]