RE: [bt-spec] BTP Issue 52 : Forms of PREPARE

[Peter Furniss <peter.furniss@choreology.com>]

 

BTP Issue 52 : Forms of PREPARE

Submitter: Mark Little, HP
Category: minor technical
Submitter's identification: #20
Description:
Page 38, last paragraph before PREPARED, talks about different forms of PREPARE. So what form is used for preparing a (sub-)coordinator?

---

 There are two distinct uses of PREPARE (see the top two paragraphs of the section):

    Superior to Inferior, seeking to elicit a PREPARED response (which means the Inferior has persisted the prepared state and recorded the Superiors address)

 

    Terminator to Composer (Decider), seeking to elicit an INFERIOR_STATUSES

 

There is a third imaginable use, related to the second, which isn't in there

   Terminator to Coordinator (Decider), seeking to elicit .....

 and the .... explains why it isn't there, because what would it return - it can't be PREPARED, because that means it has prepared itself persistently, awaiting the (persisted) decision from above, and Terminators are never persistent (by definition, in 0.9).  There's no point in the reply being INFERIOR_STATUSES, because there can be only one decision for the inferiors of the coordimator.

 

(The only way to confirm a coordinator that is not an infeiror of anything else is to ask it to confirm with REQUEST_CONFIRM.- it isn't open-topped to its Terminator.)

 

If the thing in question is a sub-coordinator, or (which is exactly equivalent for this purpose) is an atom within a cohesion, it will be enrolled as an Inferior with the superior coordinator or composer, and it gets a PREPARE (with no qualifier).

 

Suggested change: add "from a Terminator", "from a Superior" in the last paragraph of PREPARE as appropriate. (This reproduces what is said in the first paragraph but should make it clearer).