Beefy Boxes and Bandwidth Generously Provided by pair Networks
Welcome to the Monastery
 
PerlMonks  

Re: What is the difference between the constant construct in Perl and the Readonly construct in Perl?

by tfrayner (Curate)
on Jul 06, 2006 at 09:36 UTC ( #559528=note: print w/ replies, xml ) Need Help??


in reply to What is the difference between the constant construct in Perl and the Readonly construct in Perl?

Hi,

A key feature (in my view) of Readonly that others haven't mentioned yet is that a Readonly hashref will prevent you from modifying the referenced hash. The constant pragma, in contrast, only prevents you from changing the top-level reference value. The constant will always point to the same hash, but that hash can be modified. Maybe this might change in future, I don't know, but in the meantime I've been bitten by this not-entirely-constant nature of the constant pragma (inadvertently using a "constant" hash as a global variable...). It's fine for scalar and array values, but a bit dodgy for hashes, IMHO.

cheers,
Tim


Comment on Re: What is the difference between the constant construct in Perl and the Readonly construct in Perl?

Log In?
Username:
Password:

What's my password?
Create A New User
Node Status?
node history
Node Type: note [id://559528]
help
Chatterbox?
and the web crawler heard nothing...

How do I use this? | Other CB clients
Other Users?
Others having an uproarious good time at the Monastery: (4)
As of 2015-07-05 13:57 GMT
Sections?
Information?
Find Nodes?
Leftovers?
    Voting Booth?

    The top three priorities of my open tasks are (in descending order of likelihood to be worked on) ...









    Results (67 votes), past polls