bug#50143: 28.0.50; Various issues with `tamil-itrans' input method

[Eli Zaretskii <eliz@gnu.org>]

> From: Visuwesh <visuweshm@gmail.com>
> Cc: Ramesh Nedunchezian <rameshnedunchezian@outlook.com>,
>   50143@debbugs.gnu.org
> Date: Tue, 15 Feb 2022 17:31:31 +0530
> 
> >> 3. `indian-make-hash` ALWAYS installs translation for decimal digits
> >>    0-9.  Tamil decimal digits are NOT used at all i.e., it is not even
> >>    taught in Schools in the state of TamilNadu, India.  So, I wanted a
> >>    way NOT to insall the translation for digits.  I suggest one of the
> >>    following:
> >> 
> >>    - Change signature of `(indian-make-hash TABLE TRANS-TABLE)' to
> >>      `(indian-make-hash TABLE TRANS-TABLE &optional
> >>      DONT-INSTALL-NATIVE-DIGITS)' or some such thing.
> >
> > This change of the API is acceptable, so please propose a patch along
> > these lines.
> >
> 
> I wanted to send a patch so I took a quick look at ind-util.el, and ISTM
> that the hashtable `indian-tml-itrans-v5-hash' is calculated just once?
> Unfortunately, I don't understand the dances in ind-util.el,
> lisp/leim/indian.el, etc. so I'm afraid I cannot be of any help here.
> 
> [ It should be a simple change if we don't make it a defcustom AFAIU.  ]
> 
> >>      `indian-make-hash' is used by many indic scripts, so I am not
> >>      sure if other indian language users would have a need for
> >>      inputting native decimal digits.  I--as a representative of Tamil
> >>      speakers--can say that we don't need that ON by default.
> >
> > We can use this for Tamil only for now, and wait for users of other
> > languages to chime in.
> >
> > Thanks.
> 
> As a native Tamil speaker, I can attest that contemporary text uses the
> Arabic numerals (in fact, Tamil digits are mentioned as a matter of fact
> in schools).  I'm not sure about the situation in Sri Lanka, tho.

It sounds like a better way forward would be to define a separate
input method, so that the existing input method is preserved and can
be used if someone wants the current transliterations.

So my suggestions would be:

 1. For your items 1 and 3, just copy indian-tml-base-table to a new
    variable, modify it to include the two missing characters and
    replace the digits with nil, add a new variable similar to
    indian-tml-itrans-v5-hash, and compute its value like we do with
    indian-tml-itrans-v5-hash, but using the new table instead of
    indian-tml-base-table.  Then make a new input method, called, say,
    tamil-itrans-alt, which would use the new hash variable instead of
    indian-tml-itrans-v5-hash.  Submit these changes as patches to
    lisp/language/ind-util.el and lisp/leim/quail/indian.el.

 2. For your item 2, submit a patch that fixes the docstring of the
    relevant input methods.

Would that work for you?  Can you prepare such patches?