Ashley Winters skribis 2005-10-06 19:30 (-0700):
> > my Array $a = 97; # dies eventually, but when?
> Runtime -- cannot coerce Int value to Array
It is fully determinable at compile time. 97 will never be compatible
with Array, so I see no reason to wait.
Do remember that some programs run for weeks or months, rather than a
few seconds. It's nice to get all the certain failures during compile
time.
> > sub foo (Int $arg) {...}
> > foo("hello"); # should die at the latest when foo() is called
> $arg should be undef but Exception::InvalidInteger("Str value 'hello'
> cannot be coerced to an Int at $?LINE")
That'd be a problem with
sub foo (Int $arg //= 5) { ... }
because the "hello" is then silently ignored eventually. But, these
unthrown exceptions should be emitted as warnings anyway, so it is not
really a problem, because everyone has warnings enabled all the time.
I wouldn't mind this to fail. If it fails, it can die or be undef,
depending on the user's wishes. In my case: die.
> If bar returns a Str ~~ /<Perl6::Grammar::Int>/, it gets coerced;
> otherwise, undef but Exception
"hello 5 worlds"?
/^<...>/ perhaps?
And I think we should match against Num, not Int, as it's very hard to
have a rule that matches just integers. 0.5e3 is an integer, but 0.5e-3
is not.
As stated in my previous message, I think that all numbers should be
parsed the same way, and interpreted as Nums.
Juerd
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