Re: [PATCH v3 4/8] doc: give headings for the two and three dot notations

Marc Branchaud [off-list ref] writes:

quoted

+The '{caret}' (caret) notation
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  To exclude commits reachable from a commit, a prefix '{caret}'
  notation is used.  E.g. '{caret}r1 r2' means commits reachable
  from 'r2' but exclude the ones reachable from 'r1'.

All of these headings render poorly in the manpage, at least for me
(Ubuntu 16.04).  Only the first word appears in bold; the '-quoted
text is not bold but underlined, and the rest of the header is plain.


Also, I think calling this "The ^ notation" is confusing, because
there's already an earlier paragraph on the "<rev>^" syntax.

Maybe we don't need a header here?  I only suggest that because I'm
having trouble coming up with a nice alternative.  "Commit Exclusion"?

Thanks for pointing out the potential confusion between ^X (exclude
reachable), and X^ (the first parent).  Commit exclusion is probably
a good heading.

quoted

-This set operation appears so often that there is a shorthand
+The '..' (two-dot) range notation
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Perhaps "Range notation", to mirror the capitalization of "Symmetric
Difference" in the next header?

quoted

...
+The '...' (three dot) Symmetric Difference notation

This uses a strange capitalization rule.  s/notation/Notation/
perhaps?  The same comment for "Additional Shothand notation" below.

quoted

+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  A similar notation 'r1\...r2' is called symmetric difference
  of 'r1' and 'r2' and is defined as
  'r1 r2 --not $(git merge-base --all r1 r2)'.
  It is the set of commits that are reachable from either one of
  'r1' (Left side) or 'r2' (Right side) but not from both.

-In these two shorthands, you can omit one end and let it default to HEAD.
+In these two shorthand notations, you can omit one end and let it default to HEAD.
  For example, 'origin..' is a shorthand for 'origin..HEAD' and asks "What
  did I do since I forked from the origin branch?"  Similarly, '..origin'
  is a shorthand for 'HEAD..origin' and asks "What did the origin do since
  I forked from them?"  Note that '..' would mean 'HEAD..HEAD' which is an
  empty range that is both reachable and unreachable from HEAD.

Unfortunately the new headings make it appear that this paragraph is
exclusively part of the '...' notation section.  Folks reading the
..' section are likely to skip it.

I like the examples, though.  I think it would be worthwhile to remove
this paragraph and fold it explicitly into the '..' and '...' notation
sections.

An alternative would be to have

    - Dotted range notations
      - Two-dot notation
      - Three-dot notation

which would help make it stand out that defaulting is common
characteristics between .. and ... notations.  But I can imagine
that your "with slight duplication" variant below would work well,
too.

So add something like this to the '..' section (only the first
sentence here is new):

	Either r1 or r2 can be omitted, in which case HEAD is used as
	the default.  For example, 'origin..' is a shorthand for
	'origin..HEAD' and asks "What did I do since I forked from the
	origin branch?"  Similarly, '..origin' is a shorthand for
	'HEAD..origin' and asks "What did the origin do since I forked
	from them?"  Note that '..' would mean 'HEAD..HEAD' which is an
	empty range that is both reachable and unreachable from HEAD.

And also, add the same first sentence and a different example to the
...' section.  Something like this:

	Either r1 or r2 can be omitted, in which case HEAD is used as
	the default.  For example, 'origin...' is a shorthand for
	'origin...HEAD' and asks "What have I and origin both done
	since I forked from the origin branch?"  Note that 'origin...'
	and '...origin' ask the same question.

quoted

+Additional '{caret}' Shorthand notations
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  Two other shorthands for naming a set that is formed by a commit
-and its parent commits exist.  The 'r1{caret}@' notation means all
-parents of 'r1'.  'r1{caret}!' includes commit 'r1' but excludes
-all of its parents.
+and its parent commits exist.

I think descriptions of <rev>^@ and <rev>^! should live under the main
description of <rev>^.  That part already describes the numeric
suffix, so describing a couple of special suffixes there seems like a
natural fit.

I actually think this is a good place to have them described.
<rev>^<number> is about specifying a single commit.  These two are
not that (you can say HEAD^2^@ but you cannot say HEAD^@^2, for
example).