Beefy Boxes and Bandwidth Generously Provided by pair Networks
Perl-Sensitive Sunglasses

Re^4: No garbage collection for my-variables

by ikegami (Pope)
on Sep 17, 2008 at 03:02 UTC ( #711851=note: print w/replies, xml ) Need Help??

in reply to Re^3: No garbage collection for my-variables
in thread No garbage collection for my-variables

chomp( my $var = <$fh> );


chomp( my $dst = $src );
really more tedious and uglier than
my $var = chomp( scalar ( <$fh> ) );


my $dst = chomp( $src );

Replies are listed 'Best First'.
Re^5: No garbage collection for my-variables
by vrk (Chaplain) on Sep 17, 2008 at 08:20 UTC

    They are. funcall(<variable assignment>) is a useful idiom in programming languages where assigment returns (an alias to) the value of the variable, but it is counter-intuitive at first. Even though I have been programming in Perl and curly brace block syntax languages for years, I still find it hard to read -- mostly because when you normally delimit my with braces, you create a new lexical scope. That's what chomp(my $foo = bar) still seems to be, even if I know better and use the idiom frequently.

    Not only that, but it is not obvious that the value of $var in chomp(my $var = <$fh>) is being modified at all! After all, assignment, if used in other contexts, returns the value, not a reference to it. my $foo = $bar = 1 doesn't create a reference in $foo, but sets the value of both variables to 1. In fact, I am not sure what the underlying mechanism is. Does it work because assignment returns an alias similar to aliased values in @_ in function calls?

    Side-effect free chomp has no similar conceptual problems.

    say "Just Another Perl Hacker";

Log In?

What's my password?
Create A New User
Node Status?
node history
Node Type: note [id://711851]
and all is quiet...

How do I use this? | Other CB clients
Other Users?
Others exploiting the Monastery: (8)
As of 2017-12-11 15:46 GMT
Find Nodes?
    Voting Booth?
    What programming language do you hate the most?

    Results (306 votes). Check out past polls.