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

Re^5: Wrong idioms (open $fh, '<', undef)

by vsespb (Hermit)
on Mar 30, 2013 at 09:04 UTC ( #1026256=note: print w/ replies, xml ) Need Help??


in reply to Re^4: Wrong idioms (open $fh, '<', undef)
in thread Wrong idioms

I mean open does not detect error if you "open" a directory. Also last code with "wantarray" and "scalar" looks useless.


Comment on Re^5: Wrong idioms (open $fh, '<', undef)
Re^6: Wrong idioms (open $fh, '<', undef)
by Anonymous Monk on Apr 02, 2013 at 08:38 UTC

    I mean open does not detect error if you "open" a directory.

    Sure it does

    $ perl -e " open $dirname, q/../ or die $!, $/, $^E, $/ " Permission denied Access is denied $ perl -e " open $dirname, q/../ or die join qq/\n/, $!,$^E,grep( { $! +{$_} } keys %! ) " Permission denied Access is denied ERROR_INVALID_DATA EMARCH_ENC_I17_IMM5C_INST_WORD_POS_X EMR_SETBRUSHORGEX EVENT_SYSTEM_CONTEXTHELPEND EACCES at -e line 1.

    Also last code with "wantarray" and "scalar" looks useless.

    No, its is not useless. You must not know perl well.

      perl -e " open $dirname, q/../ or die $!, $/, $^E, $/ "

      You must be running Windows? or? Cygwin?

      Under linux:

      perl -e " open $dirname, q/../ or die $!, $/, $^E, $/ " bash: !,: event not found
      perl -e ' open $dirname, q/../ or die $!, $/, $^E, $/ ' (no error)

      for wantarray:

      use strict; use warnings; sub array_func { my ($arg) = @_; if (wantarray) { return map { $arg } 1..3; } else { return map { $arg*2 } 1..5; } } sub uni_func { my ($arg) = @_; return wantarray ? array_func($arg) : scalar array_func($arg); } sub small_func { my ($arg) = @_; return array_func($arg) ; } print join(';', uni_func(7)); print "\n"; print scalar(uni_func(7)); print "\n"; print join(';', small_func(7)); print "\n"; print scalar(small_func(7)); print "\n"; print join(';', array_func(7)); print "\n"; print scalar array_func(7); print "\n"; __END__ prints: 7;7;7 5 7;7;7 5 7;7;7 5
      what's the point in using 'wantarray' in uni_func here?

        You must be running Windows? or? Cygwin?

        Yeah :)

        for wantarray: ... what's the point in using 'wantarray' in uni_func here?

        clarity of intent, explicitness

Log In?
Username:
Password:

What's my password?
Create A New User
Node Status?
node history
Node Type: note [id://1026256]
help
Chatterbox?
and the web crawler heard nothing...

How do I use this? | Other CB clients
Other Users?
Others chanting in the Monastery: (6)
As of 2015-07-04 13:41 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 (60 votes), past polls