Actually, I'm not sure why we should check that at all. If someone manages
to make variable with space inside, that's his problem to get them out of
PHP symbol table later (as array index for GLOBALS or as $$var).
Anybody can explain me why we need that checking code at all?
I guess it was due to what rasmus said, not to create variables with spaces (trailing or leading).
Even Rasmus is a bit wrong, modifiying the mechanism a bit, even variables with spaces would be legal with register_globals=on .
${' SDF'}=sd;;
echo ${' SDF'};
andré