Beefy Boxes and Bandwidth Generously Provided by pair Networks
laziness, impatience, and hubris
 
PerlMonks  

Re^3: Pointers and References

by GrandFather (Saint)
on Nov 23, 2020 at 20:08 UTC ( #11124077=note: print w/replies, xml ) Need Help??


in reply to Re^2: Pointers and References
in thread Pointers and References

I don't really think of mutable arguments like that as "output parameters". "I/O parameters" maybe. I the sense that C like languages use output parameters where the sole job of the parameter is to return information from the function I don't see a need for output parameters in Perl, although passing references in the parameter list could be used that way.

The run time and memory cost of returning a reference to a large structure, or a list of references to large structures has essentially the same overhead on Perl as passing references back as parameters. Since returning a list of stuff is natural in Perl returning a list of references makes for easier to understand code than working with output parameters.

Optimising for fewest key strokes only makes sense transmitting to Pluto or beyond

Replies are listed 'Best First'.
Re^4: Pointers and References
by bliako (Prior) on Nov 24, 2020 at 01:21 UTC

    I have to say I come from C and back then (yes! Then) without goofle and the free literature it was a lot of hard work to conquer the pointers. I can't let it go now. I have often debated internally whether thinking in C while writing Perl was a good habit/idea/practice. It is NOT. But when %$^$& comes to shovel I have to think of some ways to make it faster. Because I am too lazy to program it in C eventually. And these are some of the tricks I pull.

    That's why my subs most of the times have a hashref of params as input (as opposed to array-style (file => 'aaa' , action => 'delete')) and I always return a hashref or arrayref or object back, but never ever an array. I think somewhere an angel dies when I do that. Cargo-culting perhaps, plus I am not a natural Perl-er.

    bw, bliako

      > ... as opposed to array-style ... but never ever an array ...

      Probably nitpicking: You say "array" but mean "list". :)

      Cheers Rolf
      (addicted to the Perl Programming Language :)
      Wikisyntax for the Monastery

        Thanks for pointing this out LanX

        Perhaps that's the reason I return a (array)ref: I don't want to say list! Because when I think I grasped the distinction list vs array, something proves me wrong again. But hey when in Perl speak Perl (even if some/quite-a-few publications use the terms interchangebly). I would prefer anonymous, readonly (fixed-size) array of readonly (lest they be references) items.

        But here is a quick question: you can't modify a list item in say a foreach loop foreach my $x (1,2,3){ $x = 42 } (Modification of a read-only value attempted) but in the parameter list to a sub you can: $_[0] = 12 (as jcb demonstrated earlier).

        bw, bliako

Log In?
Username:
Password:

What's my password?
Create A New User
Node Status?
node history
Node Type: note [id://11124077]
help
Chatterbox?
and the web crawler heard nothing...

How do I use this? | Other CB clients
Other Users?
Others rifling through the Monastery: (3)
As of 2021-06-13 10:18 GMT
Sections?
Information?
Find Nodes?
Leftovers?
    Voting Booth?
    What does the "s" stand for in "perls"? (Whence perls)












    Results (54 votes). Check out past polls.

    Notices?