Beefy Boxes and Bandwidth Generously Provided by pair Networks
Clear questions and runnable code
get the best and fastest answer
 
PerlMonks  

Re^2: Mystery state (possibly about whether an argument is numeric?) being maintained across calls to a sub

by vsespb (Hermit)
on Jun 15, 2013 at 18:38 UTC ( #1039141=note: print w/ replies, xml ) Need Help??


in reply to Re: Mystery state (possibly about whether an argument is numeric?) being maintained across calls to a sub
in thread Mystery state (possibly about whether an argument is numeric?) being maintained across calls to a sub

Seems no, not related to bitwise ops. Actually yes, this example shows that addition is not affected.

use Devel::Peek; use strict; no warnings "numeric"; sub xx { my $arg=shift; Dump( $arg ); print "ARG+1=".($arg+1)."\n"; } xx("ff"); xx(7); xx("ff"); __END__ SV = PV(0x729b78) at 0x754ae0 REFCNT = 1 FLAGS = (PADMY,POK,pPOK) PV = 0x747d90 "ff"\0 CUR = 2 LEN = 8 ARG+1=1 SV = PVNV(0x72b5f0) at 0x754ae0 REFCNT = 1 FLAGS = (PADMY,IOK,pIOK) IV = 7 NV = 0 PV = 0x747d90 "ff"\0 CUR = 2 LEN = 8 ARG+1=8 SV = PVNV(0x72b5f0) at 0x754ae0 REFCNT = 1 FLAGS = (PADMY,POK,pPOK) IV = 7 NV = 0 PV = 0x747d90 "ff"\0 CUR = 2 LEN = 8 ARG+1=1


Comment on Re^2: Mystery state (possibly about whether an argument is numeric?) being maintained across calls to a sub
Download Code
Re^3: Mystery state (possibly about whether an argument is numeric?) being maintained across calls to a sub
by BrowserUk (Pope) on Jun 15, 2013 at 19:20 UTC

    It's not the operation, it is whether the argument is forced from numeric to string.


    With the rise and rise of 'Social' network sites: 'Computers are making people easier to use everyday'
    Examine what is said, not who speaks -- Silence betokens consent -- Love the truth but pardon error.
    "Science is about questioning the status quo. Questioning authority".
    In the absence of evidence, opinion is indistinguishable from prejudice.
Re^3: Mystery state (possibly about whether an argument is numeric?) being maintained across calls to a sub
by cheesestraws (Novice) on Jun 16, 2013 at 09:44 UTC

    From my slightly cargo-culty perspective on what's going on here, I think that bug looks like it - especially given that non-bitwise ops don't seem to show the weirdness, and since nor does putting the constant string in a variable before doing the &:

    use Devel::Peek; use strict; no warnings "numeric"; sub xx { my $arg = shift; my $const = ""; print "(" . ($arg & $const) . ")\n"; } xx("ff"); xx(7); xx("ff");
    This code gives:
    SV = PV(0x100802558) at 0x1008474e0 REFCNT = 1 FLAGS = (PADMY,POK,pPOK) PV = 0x1002074f0 "ff"\0 CUR = 2 LEN = 8 () SV = PVIV(0x100803c58) at 0x1008474e0 REFCNT = 1 FLAGS = (PADMY,IOK,pIOK) IV = 7 PV = 0x1002074f0 "ff"\0 CUR = 2 LEN = 8 (0) SV = PVIV(0x100803c58) at 0x1008474e0 REFCNT = 1 FLAGS = (PADMY,POK,pPOK) IV = 7 PV = 0x1002074f0 "ff"\0 CUR = 2 LEN = 8 ()

      This code gives:

      Not without a call to Dump it doesn't :)

Log In?
Username:
Password:

What's my password?
Create A New User
Node Status?
node history
Node Type: note [id://1039141]
help
Chatterbox?
and the web crawler heard nothing...

How do I use this? | Other CB clients
Other Users?
Others examining the Monastery: (9)
As of 2014-09-02 17:25 GMT
Sections?
Information?
Find Nodes?
Leftovers?
    Voting Booth?

    My favorite cookbook is:










    Results (25 votes), past polls