in reply to RE: RE: lexical weirdness(?)
in thread lexical weirdness(?)
There are at least two major differences between closures and static-via-my-if-0 variables.
Here's the first. Look closely at this code and see if you can figure out what its output will be before you run it.
#!/usr/bin/perl -w use strict; { my $closure; sub func_w_closure { print "Closure! ", $closure++, "\n"; func_w_closure($_[0]+1) if $_[0] < 3; } } sub func_w_static { my $static if 0; print "Static! ", $static++, "\n"; func_w_static($_[0]+1) if $_[0] < 3; } func_w_closure(0); func_w_static(0);
I'll use tilly's spoiler trick:
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In other words, the closure is the same variable through all calls, including recursive ones, while each recursive call to the func_w_static gets its own copy.
The cool thing about that, of course, is that if you call func_w_closure again, you see that each recursive instance keeps its value!
The other difference is that closures can be shared among functions -- if you stick another function into the lexical scope of `$static' above, some_function and your new function will refer to the same variable.
-dlc
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