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From: Junio C Hamano <gitster@pobox•com>
To: Christian Couder <chriscool@tuxfamily•org>
Cc: christian.couder@gmail•com, git@vger•kernel.org,
	johan@herland•net, josh@joshtriplett•org, tr@thomasrast•ch,
	mhagger@alum•mit.edu, sunshine@sunshineco•com,
	dan.carpenter@oracle•com, greg@kroah•com, peff@peff•net
Subject: Re: [PATCH v5 02/14] trailer: process trailers from file and arguments
Date: Fri, 14 Feb 2014 16:16:26 -0800	[thread overview]
Message-ID: <xmqqppmpfcx1.fsf@gitster.dls.corp.google.com> (raw)
In-Reply-To: <xmqqtxc1fdsk.fsf@gitster.dls.corp.google.com> (Junio C. Hamano's message of "Fri, 14 Feb 2014 15:57:31 -0800")

Junio C Hamano <gitster@pobox•com> writes:

> That is, you are saying with the above
>
>      if_exists = add_if_different AND ignore_if_same
>
> So you already have to support more than one actions depending on
> the condition, ...
> of conditions, I think.  Which is essentially the same as saying
> that you need this:
>
>>     action = do_Y_if_X_and_Z AND do_U_if_V
>
> Again, unless all the U's are limited to "ignore", that is.

Oh by the way, don't get me wrong.  I am not saying that the last
one is necessarily better or worse.  I am only saying that the
semantics proposed seems to be hard to explain and we need to do
find a way to do better.

If you have these existing ones:

	Sob: A
        Sob: B
        Sob: C
        Sob: D

and you have "Sob: B" at hand, "Sob.if-missing" would not fire
(because if-exists/if-missing is only about keys) ans
"Sob.if-exists" will.  What happens is now up to the action part
(i.e. what follows "if_exists =", e.g. "add_if_different").

The conditional part of "add_if_different" action is explainable as
a conditon on the value (as opposed to condition on keys, which is
the left-hand-side).  But what does a condition with "neighbour" in
its name really mean?  It is not a condition about the value, but
also is a condition about the order of the existing records.

What is the right mental model the end-user needs to form when
understanding these?  Conditions on keys go on the left, and any
other random conditions can come as a modifier after action
e.g. add_if_same_value_is_not_at_the_end?

  reply	other threads:[~2014-02-15  0:16 UTC|newest]

Thread overview: 48+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-02-06 20:19 [PATCH v5 00/14] Add interpret-trailers builtin Christian Couder
2014-02-06 20:19 ` [PATCH v5 01/14] Add data structures and basic functions for commit trailers Christian Couder
2014-02-06 23:44   ` Junio C Hamano
2014-02-09 13:48     ` Christian Couder
2014-02-10  7:27       ` Eric Sunshine
2014-02-06 23:46   ` Junio C Hamano
2014-02-09 13:51     ` Christian Couder
2014-02-06 20:19 ` [PATCH v5 02/14] trailer: process trailers from file and arguments Christian Couder
2014-02-07  0:03   ` Junio C Hamano
2014-02-09 13:52     ` Christian Couder
2014-02-10 18:14       ` Junio C Hamano
2014-02-10 19:59         ` Christian Couder
2014-02-10 20:51           ` Junio C Hamano
2014-02-11 15:02             ` Christian Couder
2014-02-11 18:07               ` Junio C Hamano
2014-02-14 21:41                 ` Christian Couder
2014-02-14 21:46                   ` Junio C Hamano
2014-02-14 23:29                     ` Christian Couder
2014-02-14 23:39                       ` Junio C Hamano
2014-02-14 23:57                   ` Junio C Hamano
2014-02-15  0:16                     ` Junio C Hamano [this message]
2014-02-21  0:22                       ` Junio C Hamano
2014-02-23 10:44                         ` Christian Couder
2014-02-06 20:19 ` [PATCH v5 03/14] trailer: read and process config information Christian Couder
2014-02-06 20:19 ` [PATCH v5 04/14] trailer: process command line trailer arguments Christian Couder
2014-02-07  0:08   ` Junio C Hamano
2014-02-09 14:06     ` Christian Couder
2014-02-06 20:19 ` [PATCH v5 05/14] trailer: parse trailers from input file Christian Couder
2014-02-06 20:19 ` [PATCH v5 06/14] trailer: put all the processing together and print Christian Couder
2014-02-06 20:19 ` [PATCH v5 07/14] trailer: add interpret-trailers command Christian Couder
2014-02-07  0:10   ` Junio C Hamano
2014-02-07  8:34     ` Christian Couder
2014-02-07 18:09       ` Junio C Hamano
2014-02-07 20:35         ` Junio C Hamano
2014-02-06 20:19 ` [PATCH v5 08/14] trailer: add tests for "git interpret-trailers" Christian Couder
2014-02-07  0:11   ` Junio C Hamano
2014-02-06 20:19 ` [PATCH v5 09/14] trailer: if no input file is passed, read from stdin Christian Couder
2014-02-07  0:12   ` Junio C Hamano
2014-02-06 20:19 ` [PATCH v5 10/14] trailer: execute command from 'trailer.<name>.command' Christian Couder
2014-02-07  0:18   ` Junio C Hamano
2014-02-07 18:17   ` Junio C Hamano
2014-02-06 20:20 ` [PATCH v5 11/14] trailer: add tests for trailer command Christian Couder
2014-02-06 20:20 ` [PATCH v5 12/14] trailer: set author and committer env variables Christian Couder
2014-02-07  0:20   ` Junio C Hamano
2014-02-07  0:26   ` Junio C Hamano
2014-02-06 20:20 ` [PATCH v5 13/14] trailer: add tests for commands using " Christian Couder
2014-02-06 20:20 ` [PATCH v5 14/14] Documentation: add documentation for 'git interpret-trailers' Christian Couder
2014-02-10  7:17   ` Eric Sunshine

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