On 11/17/10 14:03, Moritz Lenz wrote:
Am 17.11.2010 10:31, schrieb Kris Shannon:
$duration * $duration # WRONG, durations aren't geometric
$duration * 2 # ok, a duration twice as long
2 * $duration # same
What are your thoughts?
I've summarized my thoughts here, before I read your email:
http://perlgeek.de/blog-en/perl-6/real-world-strikes-back.html
Ignoring the sarcasm, Moritz's blog and reply seem reasonable about what
should be defined by perl.
Once a number has been generated, viz., by obtaining a duration, that
number can be manipulated however necessary. The interpretation of the
number is a matter for the programmer, not the language designer.
To illustrate, lets take a different problem. Suppose we have lengths in
$x and $y, then the dimension of $a = $x * $y is of area, not of length.
Is it really consistent to forbid $x = $x * $y in case the $x may be
mistakenly interpretted as a length and not an area?
In the same vein, $duration * $duration has the physical dimension of
duration squared. True that is not the dimension of duration, and so
assigning it to a duration variable might cause a problem of physical
interpretation.
Neverthless, it doesn't seem to me that trapping dimension errors is
something a programming language should be doing.
Or am I missing something?
Richard
