patchREADME: create HTTP/HTTPS links from URLs in Markdown

Markdown supports automatic links by surrounding URLs with angle brackets, as documented in <https://daringfireball.net/projects/markdown/syntax#autolink>

While we're at it, update URLs to avoid redirecting clients for git-scm.com (by using HTTPS) and public-inbox.org (by adding a trailing slash).

Signed-off-by: Eric Wong <e@80x24.org>
---
 I was going to cite some style manuals (MLA, APA, etc),
 but it seems current versions do not favor angle brackets.
 However, this remains consistent with the recommendations in
 RFC 2369 <https://ietf.org/rfc/rfc2369.txt> for mail headers.

 README.md | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

On Wed, Mar 01, 2017 at 10:22:04PM +0000, Eric Wong wrote:

One of the joys of markdown is that there are so many variants. A lot of them (including GitHub-flavored markdown) will linkify URLs even when they're not inside angle brackets.

So I don't mind this patch, but I'm curious what's rendering the markdown you're seeing. I'd think online that one would either come across the raw text, or the GFM from https://github.com/git/git.

-Peff

Jeff King <peff@peff.net> wrote:

I was using Gruber's reference implementation from Debian stable (1.0.1-7).

Also, pandoc (also Debian stable 1.12.4.2~dfsg-1+b14) seems to require angle brackets by default. pandoc also supports the "-f markdown_github" option where it seems to behave like GFM.

But yeah, I much prefer the unambiguity of angle brackets, especially when URLs are followed immediately but punctuation such as ',' or '.'.

On Thu, Mar 02, 2017 at 07:34:21AM +0000, Eric Wong wrote:

OK. I guess my question more was "why are you doing that?". I'd expect people to find the GFM rendering on GitHub, or just look at the text via "less".

But it's not really my business why you would want to do it. :) It's reasonable for us to cater to the common subset of renderers.

-Peff

Jeff King <peff@peff.net> wrote:

Actually, I was initially seeing the lack of trailing slash causing unnecessary 301 redirects on public-inbox.org.

So, I added the trailing slash and ran "markdown <README.md" to check my work.

Then, I realized links weren't generated at all without angle brackets. So down the rabbit hole I went to read Gruber's syntax document and linkifying the rest for compatibility with Gruber's implementation.

:)

I figure somebody unfamiliar with Markdown editing README.md is likely to run the original implementation locally to check their work, as I did.

(hmm... and vger is unusually slow this week)