Re: new calendrical calculations - elisp - common lisp

[Edward Reingold <reingold@iit.edu>]

Sorry, the code in our book is NOT in the public domain and cannot be
used in Emacs.

On Mon, Jun 13, 2011 at 11:40 AM, Benjamin Slade <slade@jnanam.net> wrote:
> I would like to add a "module" to Emacs for converting from Gregorian dates
> into traditional Indian/Hindu dates (Bikrama Samvat), and, perhaps more
> importantly, for calculating Hindu holidays.
>
> I found a very nice set of functions for doing so implemented in Common Lisp
> in *Deshow, Nachum and Reingold, Edward M. 2008. _Calendrical Calculations_.
> New York: Cambridge University Press, 3rd edn*. I was wondering if this
> perhaps has already been implemented (given that Reingold developed the
> original calendar calculations for Emacs).
>
> If not: What is the best way of using this code in Emacs? I know that Emacs
> Lisp is different from Common Lisp - and I also know that there is/are
> package(s?) for using Common Lisp within Emacs.
>
> What I don't know is:
> (1) Can this code just be converted into Emacs Lisp? Or are there bits of it
> which would require Common Lisp?
>
> [Right now it doesn't work - I know that Emacs Lisp requires "defconst"
> rather than "defconstant", but even changing that, I get a "condition-case:
> Symbol's value as variable is void: 279457/1080000" error for:
>
>  (defconst hindu-sidereal-year
>   ;; TYPE rational
>   ;; Mean length of Hindu sidereal year.
>   (+ 365 279457/1080000))
>
> And changing the definition to (+ 365 (/ 1080000 279457)) it seems just to
> round.]
>
> (2) Or else, if it is necessary, how to use Common Lisp packages in Emacs.
>
> I have transcribed the code here:
> http://www.jnanam.net/emacs/hindu-calendar.el [there are probably typos in
> it yet].
>
> I'm, obviously, not really a Lisp coder, but I am looking for some pointers
> for how to get this code working within Emacs.
>
> thanks,
>   --Ben
> -----------------------------------------------------------------------------------------------------
> Benjamin Slade
> Dept. of Linguistics
> University of Illinois at Urbana-Champaign
> [ http://www.jnanam.net/slade/ ]
>
> Stæfcræft & Vyākaraṇa (lingblog) - http://staefcraeft.blogspot.com
> The Babbage Files (techblog) - http://babbagefiles.blogspot.com
>
> -----------------------------------------------------------------------------------------------------
>   परो ऽक्ष॑कामा हि देवाः
>     'The gods love the obscure.' (Śatapathabrāmaṇa 6.1.1.2)
>