Re: [PATCH 1/2] glossary-content.txt: remove an obsolete paragrah

From: Junio C Hamano <gitster@pobox.com>
Date: Nov 21, 2013, 23:55 UTC
Message-ID: <xmqqy54h1f9q.fsf@gitster.dls.corp.google.com>
In-Reply-To: <xmqqtxf54o83.fsf@gitster.dls.corp.google.com>

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

An addendum.

Show 21 quoted lines

> As we can see in a later paragaph:
>
>     The "magic signature" consists of an ASCII symbol that is not
>     alphanumeric. Currently only the slash `/` is recognized as a
>     "magic signature"...
>
> the correct way to read that "a character that cannot be a magic
> signature" is "a character that is not 'an ASCII symbol that is not
> alphanumeric'", which means you can do:
>
> 	:!/foo	- with magic signatures ! and /, pattern begins at 'f'
>
> 	:/#abc  - with magic signatures # and /, pattern begins at 'a',
> 	          even if in a particular version of Git, '#' magic
> 		  signature may be invalid and produce an error
>
> 	:/:#abc - with magic signature /, pattern is "#abc".
>
> but because the definition of "magic signature" syntax comes later
> than "cannot be", it is prone to be misinterpreted as "anything that
> is not currently defined as a magic signature (namely, '/')".

... and that misinterpretation may give a false impression that

	":/#abc"

is with the magic signature '/' (i.e. match from top) for a pattern "#abc".

Doing so would mean that a version of Git that does not support a magic signature '#' will allow people and scripts to use ":/#abc" with such a meaning, and will prevent us from using '#' as a new magic signature with some useful meaning in the future. Rather, we need to force them to always spell it as ":/:#abc" even in the version of Git before the magic signature '#'.

And the phrasing 'if the pattern begins with a character that cannot be a "magic signature" and is not a colon' needs to be clarified to avoid that misinterpretation for that reason.