Larry Wall wrote:
On Wed, Jul 27, 2005 at 06:28:22PM +0200, "TSa (Thomas Sandlaß)" wrote:
: Since we are in type hierachies these days, here's my from ::Any
: towards ::All version.
That's pretty, but if you don't move Junction upward, you haven't
really addressed the question Autrijus is asking. We're looking
for a simple type name that means none(Junction) for use as the
default type of the $x parameter to -> $x {...}. Whatever we call
it, this type/class/role/subtype has to admit Item and Pair objects
but not Junctions. (And if that's the wrong way to think about it,
please tell us why.)
Sorry, here's the patch:
: &Code @Array %Hash $Item
: | / / |
with : | Tuple Record |
invocant(s) : | |
____:____/ \______ _______|_________
| : | | \ | | | |
.Method : Sub Block | Value Inf Undef Junction
/| : |\ | |
/ | : | \ Ref[Code] |
Rule | : | Macro |
|____:_/| __________/|\___________
| : | | | | | |
Multi : | ~Str +Num \Ref :Pair /Match/
Now the Junction is nicely constraint with the upper bound Item (less
specific) and a lower bound Value (more specific). This also reads
nice if you want to (explicitly) allow both:
sub ( Value|Junction $val_junc )
What sub ( $any ) should default to, I don't know. My $Item indicates
Item, but could also be $Value. Or unspecific $(Item|Value).
--
$TSa.greeting := "HaloO"; # mind the echo!
