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Re^6: Wrong idioms (open $fh, '<', undef)

by Anonymous Monk
on Apr 02, 2013 at 08:38 UTC ( #1026620=note: print w/ replies, xml ) Need Help??


in reply to Re^5: Wrong idioms (open $fh, '<', undef)
in thread Wrong idioms

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.


Comment on Re^6: Wrong idioms (open $fh, '<', undef)
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Re^7: Wrong idioms (open $fh, '<', undef)
by vsespb (Hermit) on Apr 02, 2013 at 09:47 UTC
    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

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