Let's say that BitStream inherits from Stream::Generic. If you call BitStream's new() your way, you cannot do my $self = $class->SUPER::new(@_); to have some intialization deferred to the parent. Better is my $stream = BitStream->new("bigbinfile"); - much easier to extend, now. Plus, you could do something like:
# This way of dealing with meg and gig is a poor way, used only for de
+monstration.
# Supersearch for a better way.
my $KB = 1024;
my $MB = 1024 * $KB;
my $GB = 1024 * $MB;
my %Classes = (
$MB => 'BitStream::Vec',
$GB => 'BitStream::Buffered',
);
my $filesize = -s $filename;
my $classname = 'BitStream::InMemory';
foreach my $min_size (sort { $a <=> $b } keys %Classes)
{
last unless $filesize >= $min_size;
$classname = $classes{$min_size};
}
my $stream = $classname->new($filename);
That way, you can choose your BitStream::* class based on the size of your file. If it's under a meg, use the instream. Between a meg and a gig, use the hybrid vec option. Over a gig, you need to use the slow buffered method.
------
We are the carpenters and bricklayers of the Information Age.
The idea is a little like C++ templates, except not quite so brain-meltingly complicated. -- TheDamian, Exegesis 6
... strings and arrays will suffice. As they are easily available as native data types in any sane language, ... - blokhead, speaking on evolutionary algorithms
Please remember that I'm crufty and crochety. All opinions are purely mine and all code is untested, unless otherwise specified.
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Well, for me shoving procedures into special blocks just for the sake of static variables seems a bit cumbersome.
As compared to what? And does whatever you would compare against allow for statics to be shared amongst a variety of subs? Using the nesting feature of blocks you can set up all kinds of data relationships between subs. (However I admit that I have a Pascal background and nesting subroutines comes naturally.)
Why isn't Bitstream::new a good way of constructing an object ?
Because the implementor of Bitsteam might just go and reorganize eveything so that Bitstream doesnt have its own new, but rather inherits it from some other class, perhaps a File::Stream or more realistically IO::File. And then all of a sudden your code breaks. The point is that
Package::subroutine("is a procedure call which doesn't search \@ISA");
Package->method("is a method call which does search \@ISA");
I mean, you never know what your other personality is going to do when you aren't looking.
:-)
---
demerphq
First they ignore you, then they laugh at you, then they fight you, then you win.
-- Gandhi
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That should be BitStream->new( 'bigbinfile' ). Now your new() method can be subclassed and is a class method and not just a procedural function.
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