On 2009-Feb-23, Jonathan Worthington posted to Rakudo.org:
Applied a patch from bacek++ to get "min= and "max=" working ("$foo
min= 100" will assign 100 to $foo if it's smaller than what is in
$foo).
Nice -- except I first read that backwards, i.e. even though it
follows straight from the definition of "[op]=", it made me think of
forcing a minimum value, which would actually be max=.
I can think of a few ways to deal with this:
1) Get used to it. Maybe document it somewhere to catch fewer people
off-guard, but otherwise simply expect people to check their code.
2) Override it by defining an explicit infix:<min=> operator that does
max=, and vice versa. People like me will never notice that something
fishy is going on, but it penalizes the folks who are actually paying
attention to what "min=" ought to mean!
3) Avoid the potential for confusion by having another way to set min/
max values, such as:
$foo.min = 100;
min($foo) = 100; # lvalue function
$foo = get-foo() :min(100); # adverb on =
I'm not crazy about any of those, but that did suggest what is
probably a better way to approach it anyway: setting limits at
declaration rather than repeating them every time the variable is
assigned to:
my $foo is limited(100..200);
$foo = 5; # really does $foo = 100
-David
