class, type, instance, object, value

John Rose john.r.rose at
Mon Jun 26 18:41:49 UTC 2017

On Jun 26, 2017, at 5:16 AM, Bjorn B Vardal <bjornvar at> wrote:
>> > value field: (ambig.) field whose type is a value type (in any kind of class) OR a field in a value class (of any type)
> If you want to resolve this ambiguity, I've been referring to the former as a "value typed field" and the latter as a "value field".

Yes, that can work where the context is strong enough to keep the reader alert.
But a single letter 'd' is a slender hook to hang your meaning on, and its *absence* is even
more delicate.  Unless the context makes it very clear, I'd want to say "value class field",
or "field in a value" (ellipsis for "value class") instead of "value field" as you suggest.

(Remember, classes define fields, and then they show up in a type's API surface.
So you can usually clarify "field of some type" to "field in some class" or "field of
that type's class".  And on the other hand "field with that type" or even "field of that
type".  The word "of" is treacherous here, and "in" and "with" are more reliable.)

In some cases you have to spit out even more words to be safe: "field within value type",
"field that is a member of a value type", "field declared as a value type", "field whose type
is a value type", etc., etc.  Some of those circumlocutions benefit from ellipsis (which is
"value" standing for "value type" with the "type" clear from context).

Note that Java is already full of small ambiguities like this:  "Interface field", "inner class field",
"wrapper type field".  Perhaps we could lean harder on the class-vs-type distinction:  "Field of
an interface type" is a "field typed as an interface (type)" whereas "Field of an interface class"
is a "field declared in a class which defines an interface".

(But we don't say "interface class" at this point, and it would be hard to get folks to accept it,
even though it would clarify existing ambiguities about "class" meaning "class or interface or
enum" in many places.)

— John

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