Sorting Devanagari text -Reply

[Henry Groover]

I'm not entirely convinced that sorting Sanskrit is an intractable problem. 
Challenging but not too difficult.  I'm making a few assumptions here.  1.
The source text is Roman characters with diacritics.  One project I
worked on translated diacritical input into fully composed Devanagari
(with all the conjuncts, NOT a Hindi font) so I know it can be done (and I
believe some Sanskrit / Hindi word processors operate in a similar
manner).  2. A standard lexical order is used.  I don't have a dictionary
handy but I seem to recall that anusvara-inflected varnas come after the
identical varnas without anusvara.  This would yield the following order
for these syllables (not sure I've got the 7-bit system down):
a'sa
a.m'sa.h
aha
a.mha
A'sa
A.m'sa
kasa
ka.msa
khasa

Implementing a sort algorithm then simply requires that there is a flag or
bitmap component for the varna for anusvara or visarga.  The algorithm
would also need to compare conjuncts on a syllabic (varna) basis (but
that's fairly obvious).  The original suggestion of converting to an
intermediate system puts us on the right track; in fact, it's further
simplified by the two-dimensional arrangement of the Devanagari
aksaras.  Vowels and diphthongs are represented numerically and
combined bitwise with the distinct flag values for anusvara, visarga or
candrabindu.  If we assign hex values 01, 02 and 04 for anusvara,
candrabindu and visarga, then use hex 08 for a, 10 for A, 18 for i, 20
for I, up to 70 for au (still have one bit to spare) and A, B, C, D, E for the
first row (ka kha ga gha 'na) F, G, H, I, J for the second (ca cha ja jha
~na), etc. we would get the following for the above examples (note that
we need to preserve case sensitivity):

a'sa = 08d08
a.m'sa.h = 09d0C
aha = 08g08
a.mha = 09g08
A'sa = 10d08
A.m'sa = 11d08
kasa = A08e08
ka.msa = A09e08
khasa = B08e08

The above examples make it obvious how the sort works; numerals are
lexically lower than letters, caps lower than lowercase letters.  Handling
conjuncts fits right in, since by restricting hex values to 7 bits we've
ensured that hex values always start with a numeral.

Hence:
dvyak.sara = Rcz08Ae08a08
sa'nk.sobhya = f08EAe68XZ08
mUrdhnyA = Y30aSTz10

If anyone's interested I can produce some C source code that will do
this. It would read a list, convert it to this intermediate format, sort the
key values, and write it back sorted.

I apologize for the profuse computerese, but as Samuel Clemens once
said (more or less), "I apologize for the 5-page letter; I didn't have time to
write a short one."

Henry Groover
Hgroover at Qualitas.com.us

>>> <P.Friedlander at wellcome.ac.uk> 07/25/95 01:54pm >>>
...
However, it is clear that sorting Sanskrit may present more difficulties,
as  mentioned by Gerard Huet, than sorting Hindi.

Also as we all seem to use different Devanagari fonts (and encodings)
and  different Roman transliteration font encodings it seems that the
problem of  how to sort Devanagari will be around for a long time!

Peter Friedlander