(j3.2006) Problem with default expressions for kind type parameters?

[Bill Long]

Revising Van's example leads to another question:

type t(j,k)
    integer,kind :: j = 5
    integer,kind :: k = j+1
end type t

type(t) :: v
type(t(j=10)) :: w
print *, v%j, v%k
print *, w%j, w%k
end

Assuming this is allowed at all, what is expected for w%k?  I could see 
an argument for either 6 or 11.  I think it would be better to just 
restrict the initialization expressions for a KIND type parameter in a 
type definition to be a scalar integer constant.

Cheers,
Bill


On 9/20/12 10:17 PM, Van Snyder wrote:
> A type parameter name in a type definition is a valid primary in a
> constant expression (7.1.12p1(9)).
>
> One need not specify kind type parameter values in the declarations of
> objects of a type if there is a default in the type definition.
>
> There appears to be a problem with this:
>
>    type :: T(J=k+1,K=j+1)
>      integer, kind :: J, K
>    end type T
>
>    type(t) :: V
>
> Do we need a constraint something like this?
>
> C438a (R431) There shall not be a circular dependence between a
>        <scalar-int-constant-expr> in a <type-param-decl> and any
>        <type-param-name> in the same <type-param-decl-list>.
>
> A bigger hammer, perhaps larger than necessary, is
>
> C438a (R431) A <type-param-name> shall not appear in a
>        <scalar-int-constant-expr> in the same <type-param-decl-list>.
>
> A medium-size hammer, easier to check than the first one, is
>
> C438a (R431) A <type-param-name> that appears in a
>        <scalar-int-constant-expr> in a <type-param-decl-list> shall
>        be declared earlier in that <type-param-decl-list>.
>
> I think this is the tiniest hammer that works (maybe):
>
> C485a (R453) If there is a circular dependence between a
>        <scalar-int-constant-expr> in a <type-param-decl> and any
>        <type-param-name> in the same <type-param-decl-list>, a
>        <type-param-value> shall be provided for at least one of
>        the <type-param-name>s in the circular dependency relationship.
>
>
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-- 
Bill Long                                           longb at cray.com
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