On 12 June 2015 at 00:35, Rowan Collins <rowan.coll...@gmail.com> wrote:
> On 11/06/2015 21:22, Chris Wright wrote: > >> I'm inclined to agree that we should have consistency here, and that the >> current behaviour in a function context is the correct one. A couple of >> (IMO) good arguments for this: >> >> - The function behaviour gives a more explanatory and useful error message >> - This is definitely a programming error, there is no valid reason to use >> NULL as a variable name in this manner. It amounts to what many/most other >> languages would consider to be a "null pointer exception" or equivalent, >> and the more useful error message may help track down the error quicker >> (one might look for a case where the empty string was assigned, instead of >> looking for a case where it may be NULL). >> > > Well, if you were to model it precisely on the function case, the > *consistent* behaviour would be to error on any non-string value (e.g. $v = > 42; $$v;) but not a string which is an illegal variable name ($v = '42'; > $v(); just complains that function 42 doesn't exist, not that it never > could). > > A more useful approach would perhaps be to look at what should be a valid > function name, and what should be a valid variable name, and throw an error > if dynamic access is used to by-pass either restriction. > +1 If anything is to be done, then this should be it - properly abstract the underlying structures so that the lexical/conventional limitations on symbol naming are also imposed by mechanisms that let userland directly manipulate the names of symbols (define(), class_alias() etc). > > For instance, this doesn't currently complain about the fact that @ is > clearly nonsensical as either a function or a variable: > > $foo = '@'; > var_dump($$foo); > $foo(); > > And nor does the empty string, which seems no less obvious a bug than a > NULL: > > $foo = ''; > var_dump($$foo); > $foo(); > > > > -- > Rowan Collins > [IMSoP] > > > -- > PHP Internals - PHP Runtime Development Mailing List > To unsubscribe, visit: http://www.php.net/unsub.php > >
