[Monotone-devel] Re: magic selectors

[Richard Levitte - VMS Whacker]

Getting back to the magic selector discussion.

In message <address@hidden> on Fri, 9 Sep 2005 16:16:54 -0700, Nathaniel Smith 
<address@hidden> said:

njs> We've been resisting adding any sort of recursive syntax to
njs> selectors; to date a correct way to interpret them has been to
njs> calculate the set specified by each piece, and then intersect
njs> those sets.  Predecessor/successors/heads/disambiguate all
njs> violate this, and raise funky questions -- e.g., what order they
njs> are applied in matters.
njs> 
njs> One solution would be to define a order -- first intersective
njs> selectors, then predecessor, then successor, then head, then
njs> disambiguation.

I agree, with two exceptions:

 - I think we should require that the user types selectors in a
   correct order.
 - I'm not sure I can see how predecessor, successor and head can be
   combined in a useful way, so we might require that only one of them
   appears in a combined selector.

njs> Another solution would be to actually make them "procedural", say
njs> that they're evaluated from left to right.

I did agree with that before, so now I disagree with myself.  I think
something like H:/b:foo would be quite meaningless, rendering a
procedural model meaningless as well.  That is, unless you can give me
a practical example to the contrary...

Cheers,
Richard

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-- 
Richard Levitte                         address@hidden
                                        http://richard.levitte.org/

"When I became a man I put away childish things, including
 the fear of childishness and the desire to be very grown up."
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