Types, subtypes and pseudotypes

[Patrick Durusau <patrick@durusau.net>]

Greetings!

Before I possibly file a JIRA issue, under 4.Types I read:

> Any value has a basic type. In addition, many functions require a type 
> or a set of types with special properties (for example, a "Database" 
> requires headers that are the field names); these specialized types 
> are called /pseudotypes/. Some types (particularly Number) can be used 
> in different ways, and can thus be formatted in different ways; these 
> different uses are termed /subtypes/, since implementations typically 
> track the specific subtype to heuristically determine the default 
> formatting for newly-defined cells.
>
I was searching for use of the term "many" which really isn't meaningful 
in most cases in standards (should say which ones, not many) when I 
encountered this paragraph.

I am not sure what distinction there is between a type with "special 
properties" (pseudotype) and a type that can be used in "different ways" 
and "be formatted in different ways" (subtype).

But then I see that subtype of Number yields TRUE for ISNUMBER, even 
though OpenFormula does *not* require the tracking of subtype (at least 
that is what the text says).

OK, if we don't require subtype to be tracked, how do we require 
ISNUMBER to return TRUE for all subtypes of Number? Seems like one 
implies the other. Yes?

I am going to move onto an easier issue but I think what is required by 
OpenFormula functions needs to be consistent across those requirements.

Hope everyone is having a great day!

Patrick


-- 
Patrick Durusau
patrick@durusau.net
Chair, V1 - US TAG to JTC 1/SC 34
Convener, JTC 1/SC 34/WG 3 (Topic Maps)
Editor, OpenDocument Format TC (OASIS), Project Editor ISO/IEC 26300
Co-Editor, ISO/IEC 13250-1, 13250-5 (Topic Maps)