HN Reader

Judging by the name and by these opcodes

https://github.com/emacs-mirror/emacs/blob/7cb77385d38b96377...

it seems to be intended for character set conversion especially JIS.

I have used Emacs since 1986 or so, daily since 1989 (with smaller breaks while working at companies where it was not available). I had no idea this exists.

Here is my first CCL program.

   (define-ccl-program hw
     '(1
       (loop
        (write r0 [72 101 108 111])
        (r1 += 1)
        (if (r1 == 3) (repeat) ())
        (r0 += 1)
        (if (r0 < 4) (repeat) (break))
        )
       )
       )

   (ccl-execute-on-string
   'hw
   [0 0 0 0 0 0 0 0 1] "")

Tested in *scratch* buffer, worked. Probably not very idiomatic...

Interesting. I've been using Emacs for 6 years and have never heard of CCL. I would love to read a book on all the strange and fascinating code that Emacs has accumulated over the years.

Title should say (2019)

The source code mentioned in the article is well documented and an interesting read too; e.g.:

https://github.com/emacs-mirror/emacs/blob/master/src/ccl.c