Re: Static typing (Was Re: Better support for garbage collection)

["Ken Garlington" <Ken.Garlington@computer.org>]

"Dmitry Kazakov" <dmitry@elros.cbb-automation.de> wrote in message
news:3ac446f0.1707484@news.cis.dfn.de...
: On Thu, 29 Mar 2001 23:46:04 GMT, Robert A Duff
: <bobduff@world.std.com> wrote:
:
: >"Ken Garlington" <Ken.Garlington@computer.org> writes:
: >
: >> "Robert A Duff" <bobduff@world.std.com> wrote in message
: >> news:wccvgotscxo.fsf@world.std.com...
:
: >By the way, the "ulterior motive" in my ideas about literals is that
: >what I *really* want is user-defined literals.  I think the programmer
: >should be able to say "this type here has literals", and define which
: >forms are legal for that type, and what they mean.  But in order to
: >avoid chaos, we can't have the form of the literal affecting overload
: >resolution.
:
: I strongly support your intention (user-defined literals and surely
: user-defined aggregates), but I believe that the way is wrong. I would
: say that a literal always has a type. And its type should be
: determinable from the literal's form. I like the idea that, 1 is a
: UNIVERSAL_INTEGER, 1.0 is a UNIVERSAL_FLOAT,

Actually, 1.0 is a universal_real (see ARM 2.4:3).

: 'a' is a
: UNIVERSAL_CHARACTER etc.

Don't know exactly what a UNIVERSAL_CHARACTER is; it's an enumeration
literal of a character type (ARM 2.5:4). The only universal_types defined in
ARM 3.4.1:6 are universal_integer, universal_real, and universal_fixed.

: Then if I want to have 1 acceptable as a
: value for MY_OWN_INTEGER, or for MY_OWN_FLOAT, or even for
: MY_OWN_FILE_DESCRIPTOR, I (or the language, if the type is derived
: etc) should simply provide a conversion from UNIVERSAL_INTEGER to my
: type. Here you are.  IMO the actual problem is not inventing some
: complex overloading rules, but supporting type conversions.
:
: (For purists: there are type conversions in Ada, for instance there is
: one from a derived type to its base)
:
: Regards,
: Dmitry Kazakov