Beefy Boxes and Bandwidth Generously Provided by pair Networks
good chemistry is complicated,
and a little bit messy -LW
 
PerlMonks  

Re^3: Pattern matching with qr// and modifiers

by JavaFan (Canon)
on May 05, 2012 at 09:47 UTC ( #969031=note: print w/ replies, xml ) Need Help??


in reply to Re^2: Pattern matching with qr// and modifiers
in thread Pattern matching with qr// and modifiers

I find it surprising that adding the modifier back later has no effect, and triggers no warnings. I guess Iíll just have to remember that once a regex has been compiled with qr//, its d, i, m, s, and x settings are thereafter immutable.
Well, isn't that the point of having a compiled regexp? Now, if you compile a regexp, you know exactly what you have. Otherwise, if I have a compiled regexp, I still don't know what it does, because modifiers can be applied. It also means that if you would do something like:
my $pat = gimme_pat(); # Some method returning a qr if ($str =~ /^ $pat $ # Anchor pattern/x) { ... }
will break if $pat uses spaces.


Comment on Re^3: Pattern matching with qr// and modifiers
Select or Download Code
Replies are listed 'Best First'.
Re^4: Pattern matching with qr// and modifiers
by Athanasius (Abbot) on May 05, 2012 at 10:06 UTC

    Yes, this makes sense; but that “quotes (and possibly compiles)” in perlop is still worrying me. If I use qr// but it only quotes (and doesn’t compile), then, as you say, I still don’t really know what it does, do I?

    Thanks,

    Athanasius <°(((><contra mundum

Log In?
Username:
Password:

What's my password?
Create A New User
Node Status?
node history
Node Type: note [id://969031]
help
Chatterbox?
and the web crawler heard nothing...

How do I use this? | Other CB clients
Other Users?
Others musing on the Monastery: (13)
As of 2015-07-29 12:37 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 (263 votes), past polls