On Wed, Aug 8, 2018 at 6:50 PM Jeff King <p...@peff.net> wrote:
> On Tue, Aug 07, 2018 at 04:21:31AM -0400, Eric Sunshine wrote:
> > +# Swallowing here-docs with arbitrary tags requires a bit of finesse. When
> > a
> > +# line such as "cat <<EOF >out" is seen, the here-doc tag is moved to the
> > front
> > +# of the line enclosed in angle brackets as a sentinel, giving "<EOF>cat
> > >out".
>
> Gross, but OK, as long as we would not get confused by a line that
> actually started with <EOF> at the start.
It can't get confused by such a line. There here-doc swallower
prepends that when it starts the swallowing process and removes it add
the end. Even if a line actually started with that, it would become
"<EOF><EOF>cmd" while swallowing the here-doc, and be restored to
"<EOF>cmd" at the end. Stripping the "<EOF>" is done non-greedily, so
it wouldn't remove both of them. Likewise, non-greedy matching is used
for pulling the "EOF" out of the "<...>" when trying to match against
the terminating "EOF" line, so there can be no confusion.
> > +/<<[ ]*[-\\]*[A-Z0-9_][A-Z0-9_]*/ {
> > + s/^\(.*\)<<[ ]*[-\\]*\([A-Z0-9_][A-Z0-9_]*\)/<\2>\1<</
> > + s/[ ]*<<//
>
> Here-docs can use lowercase, too, though I'd personally frown on that
> from a style perspective.
Yeah, I was going with the tighter uppercase-only which Jonathan
suggested[1], but I guess it wouldn't hurt to re-roll to allow
lowercase too.
[1]:
https://public-inbox.org/git/20180730205914.ge156...@aiede.svl.corp.google.com/
> It looks like this doesn't catch:
>
> cat <<'EOF'
> EOF
>
> either. I think we prefer the backslash style, but there are quite a few
> <<-'EOF' hits. Is it covered somewhere else?
No. I've gotten so used to \EOF in this codebase that it didn't occur
to me to even think about 'EOF', but a re-roll could add that, as
well.
