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

Re: Less-than-helpful warnings

by Aristotle (Chancellor)
on Dec 11, 2003 at 08:54 UTC ( [id://314012]=note: print w/replies, xml ) Need Help??


in reply to Less-than-helpful warnings

There is three steps to what happens here: the values from the variables are read, then the various resulting strings are passed to a series of concatenation ops, and finally the result is passed to print.

The existence of a variable is only apparent in step 1, but reading an undefined value from a value is not and should not elicit a warning. During the concatenation step where the undef is encountered and warned about, its relation to a variable is unknown. You could just as well write

print 1 . " " . 2 . " " . 3 . " " . 4 . " " . undef;

From the concatenation operation's point of view, there's no difference to your own code.

While this situation seems trivial to a human, it is decidedly non-trivial to handle; you would need logic close to a generic partial evaluator to solve this matter.

Makeshifts last the longest.

Log In?
Username:
Password:

What's my password?
Create A New User
Domain Nodelet?
Node Status?
node history
Node Type: note [id://314012]
help
Chatterbox?
and the web crawler heard nothing...

How do I use this?Last hourOther CB clients
Other Users?
Others meditating upon the Monastery: (4)
As of 2024-03-29 10:10 GMT
Sections?
Information?
Find Nodes?
Leftovers?
    Voting Booth?

    No recent polls found