Variable Variable
Kay Schluehr
kay.schluehr at gmx.net
Sun Mar 20 06:19:05 EST 2005
> I'm going to make this explicit: the PHP idiom is a defect.
> Yes, I know that's good style among top PHP practitioners,
> but, from all I know, it's simply a bad habit. The advice to
> use a dictionary is on target.
I tried to like it the whole last hour ;-)
I reconstructed the formal structure of $$var from a PHP Web-tutorial
though i do not have any experience with the language.
This is what i got:
$ =
<Name> ---> <Var> --------------> <Var>x<String>
| |
$ | # | $ o q' o proj2
| |
V V
<Var> ----- f ------> <Var>
| |
| # | =
| V
+-----------------> <Var>x<String>
=
In the diagram $ is an operator that creates a var from a name, = is an
operator that binds a string to a var and q' drops quotations from a
string to get an name. The function f is an implied isomorphism. It
represents the equivalence of $$a and $b, where $a = "b".
Personally I could live with that, but the diagram is a bit special
because of the restriction of the = operation. I do not know if PHP
supports this operational view by enabling iterations: $a, $$a, $$$a
... ?
After all I can also live without that in Python...
Regards Kay
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