bug#21644: 24.4; completing-read acts differently on functional collection

[Dmitry Gutov]

On 10/15/2015 06:01 PM, Drew Adams wrote:

> Yes and no, IMO.  `Basic Completion' certainly provides
> some information about "completion, COLLECTION, and
> PREDICATE."  But for 3 other functions, not explicitly
> for `completing-read' - it is not even mentioned there.

What's not mentioned? Basic Completion mentions the three key functions.

> As was suggested earlier (see above), node `Programmed
> Completion' is where we should send someone for information
> about a function-valued COLLECTION argument.

Basic Completion references Programmed Completion, twice.

On the other hand, Programmed Completion assumes that the collection is 
a function from the outset. This is not necessarily true in completing-read.