Re: [PATCH] rebase -i: Fix possibly wrong onto hash in todo

Taylor Blau [off-list ref] writes:

*Grumble*, it's not anywhere in POSIX:

  https://pubs.opengroup.org/onlinepubs/9699919799/basedefs/V1_chap09.html

...making this a GNU-ism.

quoted

Look for "stick to a subset of BRE" in Documention/CodingGuidelines;
we may need to update the document to raise the baseline to match
the reality of year 2020, though.

So, I think the "reality of year 2020" is that we still write '..*'
instead of '.\+'.

Another interesting thing I found is this piece in "man sed" on
Linux (hence GNU):

    REGULAR EXPRESSIONS
           ...
           The -E option switches to using extended regular  expressions  instead;
           it  has  been  supported  for  years by GNU sed, and is now included in
           POSIX.

But the "sed" documentation [*1*] that matches what you cited above (The
Open Group Base Specifications Issue 7, 2018 edition) does not
mention "-E", "-r" nor "--regexp-extended".


[Reference]

*1*
https://pubs.opengroup.org/onlinepubs/9699919799/utilities/sed.html#tag_20_116_02