.. but when the same is done in a loop, with a lexical variable declared beforehand, the result changes:

because a loop is a block of it's own which changes. IIRC the essence of closures is that whenever the outer block is entered (decided at run-time!) the my variables are associated to another lexpad (please correct my terminology if I name something wrong).

so with 

for my $var ( 1,2,3) { 
  my $x =sub {print $var }
}

[download]

the opcode for $var points for each run into different instances of the lexpads of the for loop.

UPDATE ----

it's more like this in pseudocode

 while ( $LEXPAD{for-block}={}; "$LEXPAD{for-block}"->{var} = (1,2,3)-
+>next() ) {
  my $x =sub { print  "$LEXPAD{for-block}"->{var} }
}

[download]

----- UPDATE

OTOH there is nothing like a "closure with packagevars", they always point to the same symboltable (decided at compile-time!)

Now the extra complexity comes because ELISHEVA declares the loop variable in advance with my / our, which implies localising, i.e. saving and restoring the variable at runtime. (Nota bene: Normally there is nothing like local() with lexvars)

Cheers Rolf

In reply to Re^3: How do closures and variable scope (my,our,local) interact in perl? by LanX
in thread How do closures and variable scope (my,our,local) interact in perl? by ELISHEVA

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