It is not what is executed in the else block, but what is execute after.

if (expression) {
    statement (1);
    }
else {
    statement (2);
    }
statement (3);

[download]

If statement (1) exits the enclosing scope with return/exit/die/croak, statement (3) is never executed. An if/else is the to do something different based on a condition and then continue doing what is after the construct for all cases. This implies that an else immediately after return/exit/die/croak is always useless.

The original code does it right in the first block: 

sub get_filehandle {
    my $self = shift;
    $self->{file} = shift;
    open my $fh, "<", $self->{file}
        or die "can't open $self->{file}";
    return $fh;
    }

[download]

Which - when following the wrong method you approve of - would be

sub get_filehandle {
    my $self = shift;
    $self->{file} = shift;
    if (open my $fh, "<", $self->{file}) {
        return $fh;
        }
    else {
        die "can't open $self->{file}";
        }
    }

[download]

In my way, the second block should be reduced to

sub get_lines {
    my $self = shift;
    $self->{file} = shift;
    ### get the filehandle if we don't already have one
    $self->{file_handle} ||= $self->get_filehandle ($self->{file});
    return readline ($self->{file_handle}) || undef;
    }

[download]

That last return is arguable anyway, as the readline method can be a method that legally can return undef, "", and 0 (or any object evaluating as false) indicating that the original code was wrong to start with.


Enjoy, Have FUN! H.Merijn

In reply to Re^5: What's the right way to write a method which returns one line at a time from a file? by Tux
in thread What's the right way to write a method which returns one line at a time from a file? by Cody Fendant

Title:
Use:  <p> text here (a paragraph) </p>
and:  <code> code here </code>
to format your post, it's "PerlMonks-approved HTML":


  • Posts are HTML formatted. Put <p> </p> tags around your paragraphs. Put <code> </code> tags around your code and data!
  • Titles consisting of a single word are discouraged, and in most cases are disallowed outright.
  • Read Where should I post X? if you're not absolutely sure you're posting in the right place.
  • Please read these before you post! —
  • Posts may use any of the Perl Monks Approved HTML tags:
    a, abbr, b, big, blockquote, br, caption, center, col, colgroup, dd, del, details, div, dl, dt, em, font, h1, h2, h3, h4, h5, h6, hr, i, ins, li, ol, p, pre, readmore, small, span, spoiler, strike, strong, sub, summary, sup, table, tbody, td, tfoot, th, thead, tr, tt, u, ul, wbr
  • You may need to use entities for some characters, as follows. (Exception: Within code tags, you can put the characters literally.)
            For:     Use:
    & &amp;
    < &lt;
    > &gt;
    [ &#91;
    ] &#93;
  • Link using PerlMonks shortcuts! What shortcuts can I use for linking?
  • See Writeup Formatting Tips and other pages linked from there for more info.