On Mon, May 02, 2005 at 03:04:57AM -0600, Luke Palmer wrote:
: S12 says:
:
: subtype Str_not2b of Str where /^[isnt|arent|amnot|aint]$/;
:
: My brain parses this as:
:
: subtype Str_not2b[Str where /.../];
:
: Or:
:
: subtype Str_not2b[Str] where /.../;
:
: Neither of which really reflect how it is really parsed.
It's closer to the former, but perhaps more like
subtype Str_not2b[returns => :(Str where /.../)];
: It looks like
: `subtype` has a special syntax. I find this to be free of special
: syntax and clearer to boot:
:
: type Str_not2b ::= Str where /^[isnt|arent|amnot|aint]$/;
I don't. That "type" keyword is just a strange way to write the
"::" sigil.
: Why don't we just ditch the `subtype` keyword?
Because by similar arguments we should also disallow
sub foo ($x, $y, $z) {...}
class Dog is Mammal {...}
in favor of
&foo ::= sub ($x, $y, $z) {...}
::Dog ::= class is Mammal {...}
I'd rather have most declarative keywords out front, and reserve ::=
for bindings that require unusual calculations on the RHS. Though as
Thomas pointed out, you can still write
::Str_not2b ::= Str where /^[isnt|arent|amnot|aint]$/;
if you really want to.
Larry
