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diff --git a/contrib/snowball/algorithms/hindi.sbl b/contrib/snowball/algorithms/hindi.sbl new file mode 100644 index 0000000..bfdfac0 --- /dev/null +++ b/contrib/snowball/algorithms/hindi.sbl @@ -0,0 +1,323 @@ +// An implementation of "A Lightweight Stemmer for Hindi": +// http://www.kbcs.in/downloads/papers/StmmerHindi.pdf + +externals ( stem ) + +stringescapes {} + +// The transliteration scheme used for our stringdefs matches that used in the +// paper, as documented in the appendix. It appears to match the WX notation +// (https://en.wikipedia.org/wiki/WX_notation) except that WX apparently +// uses 'z' for Anunasika whereas the paper uses Mh. +// +// We discriminate dependent vowels by adding a leading "_" to their stringdef +// names (mnemonic: the _ signifies removing the implicit a from the preceding +// character). + +// Vowels and sonorants: +stringdef a '{U+0905}' +stringdef A '{U+0906}' +stringdef i '{U+0907}' +stringdef I '{U+0908}' +stringdef u '{U+0909}' +stringdef U '{U+090A}' +stringdef q '{U+090B}' +stringdef e '{U+090F}' +stringdef E '{U+0910}' +stringdef o '{U+0913}' +stringdef O '{U+0914}' + +// Vowel signs: +stringdef _A '{U+093E}' +stringdef _i '{U+093F}' +stringdef _I '{U+0940}' +stringdef _u '{U+0941}' +stringdef _U '{U+0942}' +stringdef _q '{U+0943}' +stringdef _e '{U+0947}' +stringdef _E '{U+0948}' +stringdef _o '{U+094B}' +stringdef _O '{U+094C}' + +// Diacritics: +stringdef M '{U+0902}' +stringdef H '{U+0903}' +stringdef Mh '{U+0901}' +stringdef Z '{U+093C}' // Nukta +stringdef virama '{U+094D}' + +// Velar consonants: +stringdef k '{U+0915}' +stringdef K '{U+0916}' +stringdef g '{U+0917}' +stringdef G '{U+0918}' +stringdef f '{U+0919}' + +// Palatal consonants: +stringdef c '{U+091A}' +stringdef C '{U+091B}' +stringdef j '{U+091C}' +stringdef J '{U+091D}' +stringdef F '{U+091E}' + +// Retroflex consonants: +stringdef t '{U+091F}' +stringdef T '{U+0920}' +stringdef d '{U+0921}' +stringdef D '{U+0922}' +stringdef N '{U+0923}' + +// Dental consonants: +stringdef w '{U+0924}' +stringdef W '{U+0925}' +stringdef x '{U+0926}' +stringdef X '{U+0927}' +stringdef n '{U+0928}' + +// Labial consonants: +stringdef p '{U+092A}' +stringdef P '{U+092B}' +stringdef b '{U+092C}' +stringdef B '{U+092D}' +stringdef m '{U+092E}' + +// Semi-vowels: +stringdef y '{U+092F}' +stringdef r '{U+0930}' +stringdef l '{U+0932}' +stringdef v '{U+0935}' + +// Fricatives: +stringdef S '{U+0936}' +stringdef R '{U+0937}' +stringdef s '{U+0938}' +stringdef h '{U+0939}' + +stringdef lY '{U+0933}' + +// Precomposed characters - letters + nukta: +stringdef nZ '{U+0929}' // ≡ {n}{Z} +stringdef rZ '{U+0931}' // ≡ {r}{Z} +stringdef lYZ '{U+0934}' // ≡ {lY}{Z} +stringdef kZ '{U+0958}' // ≡ {k}{Z} +stringdef KZ '{U+0959}' // ≡ {K}{Z} +stringdef gZ '{U+095A}' // ≡ {g}{Z} +stringdef jZ '{U+095B}' // ≡ {j}{Z} +stringdef dZ '{U+095C}' // ≡ {d}{Z} +stringdef DZ '{U+095D}' // ≡ {D}{Z} +stringdef PZ '{U+095E}' // ≡ {P}{Z} +stringdef yZ '{U+095F}' // ≡ {y}{Z} + +integers ( p ) + +groupings ( consonant ) + +routines ( CONSONANT ) + +define consonant '{k}{K}{g}{G}{f}' + + '{c}{C}{j}{J}{F}' + + '{t}{T}{d}{D}{N}' + + '{w}{W}{x}{X}{n}' + + '{p}{P}{b}{B}{m}' + + '{y}{r}{l}{v}' + + '{S}{R}{s}{h}' + + '{lY}' + + '{Z}' + // Nukta + // Precomposed characters - letter and nukta: + '{nZ}{rZ}{lYZ}{kZ}{KZ}{gZ}{jZ}{dZ}{DZ}{PZ}{yZ}' + +backwardmode ( define CONSONANT as ( consonant ) ) + +define stem as ( + test ( next setmark p ) + backwards ( + // We assume in this implementation that the whole word doesn't count + // as a valid suffix to remove, so we remove the longest suffix from + // the list which leaves at least one character. This change affects + // 47 words out of the 65,140 in the sample vocabulary from Hindi + // wikipedia. + setlimit tomark p for ([substring]) + among ( + // The list below is derived from figure 3 in the paper. + // + // We perform the stemming on the Devanagari characters rather than + // transliterating to Latin, so we have adapted the list below to + // reflect this by converting suffixes back to Devanagari as + // follows: + // + // * within the suffixes, "a" after a consonant is dropped since + // consonants have an implicit "a". + // + // * within the suffixes, a vowel other than "a" after a consonant + // is a dependent vowel (vowel sign); a vowel (including "a") + // after a non-consonant is an independent vowel. + // + // * to allow the vowel at the start of each suffix being dependent + // or independent, we include each suffix twice. For the + // dependent version, a leading "a" is dropped and we check that + // the suffix is preceded by a consonant (which will have an + // implicit "a"). + // + // * we add '{a}', which is needed for the example given right at + // the end of section 5 to work (conflating BarawIya and + // BarawIyawA), and which 3.1 a.v strongly suggests should be in + // the list: + // + // Thus, the following suffix deletions (longest possible + // match) are required to reduce inflected forms of masculine + // nouns to a common stem: + // a A i [...] + // + // Adding '{a}' only affect 2 words out of the 65,140 in the + // sample vocabulary. + // + // * The transliterations of our stems would end with "a" when our + // stems end in a consonant, so we also include {virama} in the + // list of suffixes to remove (this affects 222 words from the + // sample vocabulary). + // + // We've also assumed that Mh in the suffix list always means {Mh} + // and never {M}{h}{virama}. Only one of the 65,140 words in the + // sample vocabulary stems differently due to this (and that word + // seems to be a typo). + + '{virama}' + + '{a}' + '{A}' + '{i}' + '{I}' + '{u}' + '{U}' + '{e}' + '{o}' + '{e}{M}' + '{o}{M}' + '{A}{M}' + '{u}{A}{M}' + '{u}{e}{M}' + '{u}{o}{M}' + '{A}{e}{M}' + '{A}{o}{M}' + '{i}{y}{_A}{M}' + '{i}{y}{_o}{M}' + '{A}{i}{y}{_A}{M}' + '{A}{i}{y}{_o}{M}' + '{A}{Mh}' + '{i}{y}{_A}{Mh}' + '{A}{i}{y}{_A}{Mh}' + '{a}{w}{_A}{e}{M}' + '{a}{w}{_A}{o}{M}' + '{a}{n}{_A}{e}{M}' + '{a}{n}{_A}{o}{M}' + '{a}{w}{_A}' + '{a}{w}{_I}' + '{I}{M}' + '{a}{w}{_I}{M}' + '{a}{w}{_e}' + '{A}{w}{_A}' + '{A}{w}{_I}' + '{A}{w}{_I}{M}' + '{A}{w}{_e}' + '{a}{n}{_A}' + '{a}{n}{_I}' + '{a}{n}{_e}' + '{A}{n}{_A}' + '{A}{n}{_e}' + '{U}{M}{g}{_A}' + '{U}{M}{g}{_I}' + '{A}{U}{M}{g}{_A}' + '{A}{U}{M}{g}{_I}' + '{e}{M}{g}{_e}' + '{e}{M}{g}{_I}' + '{A}{e}{M}{g}{_e}' + '{A}{e}{M}{g}{_I}' + '{o}{g}{_e}' + '{o}{g}{_I}' + '{A}{o}{g}{_e}' + '{A}{o}{g}{_I}' + '{e}{g}{_A}' + '{e}{g}{_I}' + '{A}{e}{g}{_A}' + '{A}{e}{g}{_I}' + '{A}{y}{_A}' + '{A}{e}' + '{A}{I}' + '{A}{I}{M}' + '{i}{e}' + '{A}{o}' + '{A}{i}{e}' + '{a}{k}{r}' + '{A}{k}{r}' + + '{_A}' + '{_i}' + '{_I}' + '{_u}' + '{_U}' + '{_e}' + '{_o}' + '{_e}{M}' + '{_o}{M}' + '{_A}{M}' + '{_u}{A}{M}' + '{_u}{e}{M}' + '{_u}{o}{M}' + '{_A}{e}{M}' + '{_A}{o}{M}' + '{_i}{y}{_A}{M}' + '{_i}{y}{_o}{M}' + '{_A}{i}{y}{_A}{M}' + '{_A}{i}{y}{_o}{M}' + '{_A}{Mh}' + '{_i}{y}{_A}{Mh}' + '{_A}{i}{y}{_A}{Mh}' + '{_I}{M}' + '{_A}{w}{_A}' + '{_A}{w}{_I}' + '{_A}{w}{_I}{M}' + '{_A}{w}{_e}' + '{_A}{n}{_A}' + '{_A}{n}{_e}' + '{_U}{M}{g}{_A}' + '{_U}{M}{g}{_I}' + '{_A}{U}{M}{g}{_A}' + '{_A}{U}{M}{g}{_I}' + '{_e}{M}{g}{_e}' + '{_e}{M}{g}{_I}' + '{_A}{e}{M}{g}{_e}' + '{_A}{e}{M}{g}{_I}' + '{_o}{g}{_e}' + '{_o}{g}{_I}' + '{_A}{o}{g}{_e}' + '{_A}{o}{g}{_I}' + '{_e}{g}{_A}' + '{_e}{g}{_I}' + '{_A}{e}{g}{_A}' + '{_A}{e}{g}{_I}' + '{_A}{y}{_A}' + '{_A}{e}' + '{_A}{I}' + '{_A}{I}{M}' + '{_i}{e}' + '{_A}{o}' + '{_A}{i}{e}' + '{_A}{k}{r}' + + /* Suffixes with a leading implicit a: */ + '{w}{_A}{e}{M}' CONSONANT + '{w}{_A}{o}{M}' CONSONANT + '{n}{_A}{e}{M}' CONSONANT + '{n}{_A}{o}{M}' CONSONANT + '{w}{_A}' CONSONANT + '{w}{_I}' CONSONANT + '{w}{_I}{M}' CONSONANT + '{w}{_e}' CONSONANT + '{n}{_A}' CONSONANT + '{n}{_I}' CONSONANT + '{n}{_e}' CONSONANT + '{k}{r}' CONSONANT + ) + delete + ) +) |