Another option could be:

# The following sub uses the following aliases:
# I: [0] - $self
# I: [1] - value
# C: [2] - some temp space I use to calculate
sub {
}
[download]

When did comments become passee? Self-commmenting code is nice, but if you're doing black magic for performance reasons, you will need to comment outside the code.

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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

Please remember that I'm crufty and crochety. All opinions are purely mine and all code is untested, unless otherwise specified.