Decipher auto-mode-alist regexp and unbreak .yml support

[Hi-Angel]

I noticed that .yml files are not being opened in YAML mode. Further research showed almost unreadable regular expression, which apparently supposed to support .yml files, but failed to do so. Digging into the history to see what exactly extensions were supposed to be supported by this regexp showed:

• raml — commit c4fd940
• eyaml — commit 11df403
• yml, yaml — prior to above commits

So use rx macro to enlist aforementioned extensions explicitly, and unbreak support for yml at the same time.

CC: @rhoml @scop

[Hi-Angel]

Oh, turns out it's being tested, I'm wondering why yml though wasn't working then. Okay, judging by tests there's also unmentioned eyml, let me add it.

[Hi-Angel]

lol, I was wondering why my addition of eyml didn't fix the tests. Turned out, I "fixed it" on .el file opened from ELPA and not in the repo. Okay, now it's passing.

[syohex]

I noticed that .yml files are not being opened in YAML mode.

I'm afraid this is not correct. The regexp matches against .yml files. You can check it by writing some s-expressions like, (string-match-p "\\.\\(e?ya?\\|ra\\)ml\\'" "foo.yml") . This expression returns non-nil value, this means the regexp matches against "foo.yml". Or you can check it by emacs -Q -l yaml-mode.el test.yml

Please check if you use the latest version. If it doesn't fix your problem, please check your configuration files.

BTW I think emacs developers are familiar with elisp regexp so we don't need to use rx macros for such simple regexps. It is not easy to read elisp regexp with default face configurations, so I recommend changing those face configurations.

(set-face-foreground 'font-lock-regexp-grouping-backslash "brightmagenta")
(set-face-foreground 'font-lock-regexp-grouping-construct "brightgreen")

[Hi-Angel]

BTW I think emacs developers are familiar with elisp regexp so we don't need to use rx macros for such simple regexps. It is not easy to read elisp regexp with default face configurations, so I recommend changing those face configurations.

I feel like this is already a lost battle… but don't you think regexp optimization is better left to rx macro, because it turns human readable list of extensions to a unreadable regexp just as you like. I think most people are not masterminds who can decompile such regular expression to a list of meaningless words "yml", "eyml", etc.

[Hi-Angel]

think most people are not masterminds who can decompile such regular expression to a list of meaningless words "yml", "eyml", etc

Don't get me wrong: I can do that given enough time. Like, spending ½ an hour… But why bother if you can have the list right away 🤷‍♂️

[Hi-Angel]

Btw, if you consider this regexp so readable, why did you add a test that makes sure that the mode gets enabled for all extensions. I mean, it's hard to introduce a bug to this string, right?