On Tue, Sep 11, 2012 at 10:25:03PM +0100, Nicholas Clark wrote:
: On Tue, Sep 11, 2012 at 11:11:11PM +0200, Carl Mäsak wrote:
: > Nicholas (>):
: > > Where in the synopses (or other documents) does it explain why these two
: > > are different?
: > >
: > > $ ./perl6 -e 'sub foo {state @a = (3, 4); say ++@a[0];}; foo; foo;'
: > > 4
: > > 5
: > > $ ./perl6 -e 'sub foo {(state @a) = (3, 4); say ++@a[0];}; foo; foo;'
: > > 4
: > > 4
: >
: > S03:4912. "Each declarator can take an initializer following an equals
: > sign (which should not be confused with a normal assignment, because
: > the timing of the initialization depends on the natural lifetime of
: > the container, which in turn depends on which declarator you use)."
:
: Thanks, but if I read that I wouldn't make this jump from it:
:
: > In other words, the parens turn the special equals sign into normal
: > assignment again.
:
: (which I'm fine with, as a reason. Although my mental model of it was
: "When it's a statement, it's special, with an implied phaser block.
: If it's part of an expression, however trivial, it can't be special")
There is no sense in which a declarator is a statement. (Not even in
Perl 5.) A declarator is simply a term. The difference from Perl 5
is that in Perl 6, declarators are kinda like macros that can look for
more arguments, and the initializer argument happens to be labelled
with an '=' instead of something like :init(42). The extra parens just
do term isolation in this case.
: So I guess my next question is "where is normal assignment explained?"
: Specifically, the part that would explain that you can put C<my> or C<our>
: or similar within the list on the left of the C<=>.
Er, why would normal assignment want to explain something that isn't normal?
Anyway, normal assignment is also explained in S03, albeit somewhat diffusely.
Larry
