# sanskrit
Every other module in ganapati builds on the constants and functions
here. They deal with three things that come up whenever you index
Sanskrit: the Vedic accent marks that a search should ignore, the many
ways one word can be spelled (Devanagari, IAST, plain ASCII), and the
citations that label verses in an edition, such as `MBh_1,1.1`. None of
them needs litesearch.
A few constants are used throughout. `DANDA` (।) and `DDANDA` (॥) are
the single and double daṇḍa, the marks that close a half-verse and a
verse. `VIRAMA` is the sign that removes a consonant’s built-in `a`.
`DEVANAGARI` is a regular expression that matches any Devanagari
character, including the Vedic extension blocks, and `VEDIC_MARKS`
matches the accent marks alone.
/opt/hostedtoolcache/Python/3.12.15/x64/lib/python3.12/site-packages/usearch/__init__.py:131: UserWarning: Will download `usearch_sqlite` binary from GitHub.
warnings.warn("Will download `usearch_sqlite` binary from GitHub.", UserWarning)
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source
### roman_fold
``` python
def roman_fold(
s:str, doubles:bool=False, # make doubled letters single, so Kārttikeya and Kartikeya give one key
endings:bool=False, # cut an English plural or past-tense ending when three letters remain, so duties and duty give one key
)->str:
```
*Fold like
[`fold_token`](https://vedicreader.github.io/ganapati/sanskrit.html#fold_token),
then also merge informal English spellings (sh to s, th to t, ee to i,
oo to u, w to v), so Bheeshma and Bhīṣma both give `bisma`.*
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source
### fold_token
``` python
def fold_token(
s:str
)->str:
```
*Return the plain-ASCII search key for one token in any script: `भीष्म`
and `Bhīṣma` both give `bhisma`.*
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source
### detect_script
``` python
def detect_script(
s:str
)->str:
```
*Say whether `s` is mostly Devanagari (`'deva'`), Latin (`'latn'`) or
neither (`'other'`).*
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source
### deva2ascii
``` python
def deva2ascii(
s:str
)->str:
```
*Transliterate Devanagari to plain ASCII without diacritics, writing the
implicit `a` after each unmarked consonant.*
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source
### strip_vedic
``` python
def strip_vedic(
s:str
)->str:
```
*Remove Vedic tone marks from Devanagari text, leaving Latin diacritics
alone, and return it in NFC form.*
[`strip_vedic`](https://vedicreader.github.io/ganapati/sanskrit.html#strip_vedic)
removes the udātta, anudātta and other tone marks from Devanagari and
keeps the letters, so अ॒ग्निमी॑ळे becomes अग्निमीळे. Latin diacritics such as
the macron in ā are left alone.
[`fold_token`](https://vedicreader.github.io/ganapati/sanskrit.html#fold_token)
gives one token its search key: lowercase ASCII with no diacritics and
no vowel length. Devanagari goes through
[`deva2ascii`](https://vedicreader.github.io/ganapati/sanskrit.html#deva2ascii),
which writes out each consonant’s implicit `a`, and Latin text just
loses its accents, so भीष्म and Bhīṣma both fold to `bhisma`. A search
index applies the same key to the stored text and to the query, which is
how a reader who types `bhisma` finds भीष्म. The function is cached,
since a corpus repeats a small vocabulary many times.
[`detect_script`](https://vedicreader.github.io/ganapati/sanskrit.html#detect_script)
says whether a string is mostly Devanagari, Latin or neither.
[`roman_fold`](https://vedicreader.github.io/ganapati/sanskrit.html#roman_fold)
goes further, for names and words typed in the informal spellings of
Indian English. After
[`fold_token`](https://vedicreader.github.io/ganapati/sanskrit.html#fold_token)
it drops the h of an aspirate (sh, th and bh become s, t and b), reads
`ee` and `oo` as `i` and `u`, makes a vowel written twice single, reads
`ri` before a consonant as the vowel ṛ, and treats `w` as `v`. Bheeshma
and Bhīṣma both become `bisma`. Two options loosen it more:
`doubles=True` makes doubled letters single, and `endings=True` cuts an
English plural or past-tense ending. Use
[`fold_token`](https://vedicreader.github.io/ganapati/sanskrit.html#fold_token)
for text in a proper transliteration and
[`roman_fold`](https://vedicreader.github.io/ganapati/sanskrit.html#roman_fold)
for text typed by someone writing English. The cell below checks each of
these.
``` python
test_eq(strip_vedic('अ॒ग्निमी॑ळे'), 'अग्निमीळे')
test_eq(fold_token('भीष्म'), 'bhisma')
test_eq(fold_token('Bhīṣma'), 'bhisma')
test_eq(roman_fold('Bheeshma'), 'bisma')
test_eq(detect_script('धर्म'), 'deva')
```
A citation is how GRETIL and similar editions label a verse. It is an
abbreviation for the work, called a siglum, followed by the verse’s
place in it: `|| MBh_1,1.1 ||` is the Mahābhārata, book 1, chapter 1,
verse 1. `CITE_RE` finds a citation between `||` or `//` markers in
running text, and
[`cite_parts`](https://vedicreader.github.io/ganapati/sanskrit.html#cite_parts)
splits one into the siglum and its list of numbers. A number for another
edition in square brackets, as in `IsUp_4[57M]`, is dropped.
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source
### cite_parts
``` python
def cite_parts(
c:str
)->tuple:
```
*Split a citation id into its siglum and its numbers: `'BrhUp_1,1.2'`
gives `('BrhUp', ['1', '1', '2'])`.*
``` python
test_eq(cite_parts('BrhUp_1,1.2'), ('BrhUp', ['1', '1', '2']))
assert CITE_RE.search('atha || MBh_1,1.1 ||')
```