...each line is interpreted and executed before proceeding to the next line.

Test your intuition:

while( <DATA> ) {
    chomp;
    if( is_empty($_) ) {
        print "$.: ---\n" if is_empty($_);
    }
    else {
        print "$.: $_\n";
    }
    goto JUMP if $. == 4;
}

sub is_empty {
    return ! length $_[0];
}


BEGIN { print "Beginning execution.\n" }

JUMP: { print "Look, found the JUMP block.\n"; }

__DATA__
First line

Third line
Fourth line
Fifth line

[download]

So... the BEGIN{} block executes before everything else. So Perl must have known about it even though it appears physically lower in the file. The is_empty function is declared and defined after it is called, so Perl must have known about it when it executed the line "if( is_empty(...". And the <DATA> filehandle is being read even though its contents appear at the end of the file. And last but not least, goto found JUMP.


Dave

In reply to Re: Perl execution by davido
in thread Perl execution by rbala

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