A Catalan stemming algorithm


Links to resources

Snowball main page
Tar-gzipped file of the delivered resources
Catalan suffixes (as referenced below)
Catalan irregular verbs (as referenced below)

A stemmer for Catalan was sent us by Israel Olalla of iSOCO with this accompanying email:
From: Israel Olalla Date: Mon, 26 Jul 2010 12:25:44 +0200 Subject: Catalan Snowball Stemmer Hi, Here you can find a valid version of the Catalan stemmer. It has been tested and reviewed using the dictionary included with freeling and works fine. To find the suffixes we've used, see: http://wapedia.mobi/ca/Llista_de_sufixos And for irregular verbs: http://ca.wikipedia.org/wiki/Flexi%C3%B3_verbal_del_catal%C3%A0 We are open, to feedback and discussion about the linguistics, and about the snowball implementation i finally did.
Please distribute this freely, with a mention of the author and of the company iSOCO, that has let us share our work freely with the Snowball community. Kind Regards, Israel Olalla
[For distribution, see the note for the Basque stemmer. Our thanks to iSOCO!]

Here is the script of the stemmer in Snowball,

routines ( cleaning mark_regions R1 R2 attached_pronoun standard_suffix verb_suffix residual_suffix ) externals ( stem ) integers ( p1 p2 ) groupings ( v ) stringescapes {} /* special characters (in ISO Latin I) */ stringdef a' hex 'E1' // a-acute stringdef a` hex 'E0' // a-grave stringdef c, hex 'E7' // c-cedilla stringdef e' hex 'E9' // e-acute stringdef e` hex 'E8' // e-grave stringdef i' hex 'ED' // i-acute stringdef i` hex 'EC' // i-grave stringdef i" hex 'EF' // i-diaeresis stringdef o' hex 'F3' // o-acute stringdef o` hex 'F2' // o-grave stringdef u' hex 'FA' // u-acute stringdef u" hex 'FC' // u-diaeresis stringdef - hex '2D' // - per aggeminades stringdef . hex 'B7' // - per l aggeminades define v 'aeiou{a'}{a`}{e'}{e`}{i'}{i"}{o'}{o`}{u'}{u"}' define mark_regions as ( $p1 = limit $p2 = limit // defaults do ( gopast v gopast non-v setmark p1 gopast v gopast non-v setmark p2 ) ) define cleaning as repeat ( [substring] among( '{a'}' (<- 'a') '{a`}' (<- 'a') '{e'}' (<- 'e') '{e`}' (<- 'e') '{i'}' (<- 'i') '{i`}' (<- 'i') '{o'}' (<- 'o') '{o`}' (<- 'o') '{u'}' (<- 'u') '{u"}' (<- 'u') '{i"}' (<- 'i') '{.}' (<- '.') '' (next) ) //or next ) backwardmode ( define R1 as $p1 <= cursor define R2 as $p2 <= cursor define attached_pronoun as ( [substring] among ( '{'}s' '{'}hi' '{'}ho' '{'}l' '{'}ls' '{-}ls' '{-}la' '{-}les' '{-}li' 'vos' 'se' 'nos' '{-}nos' '{-}us' 'us' '{'}n' '{'}ns' '{-}n' '{-}ns' '{'}m' '{-}me' '{-}m' '{-}te' '{'}t' 'li' 'lo' 'los' 'me' 'sela' 'selo' 'selas' 'selos' 'le' 'la' 'las' 'les' 'ens' 'ho' 'hi' (R1 delete) ) ) define standard_suffix as ( [substring] among( 'ar' 'atge' 'formes' 'icte' 'ictes' 'ell' 'ells' 'ella' '{e'}s' '{e`}s' 'esc' 'essa' 'et' 'ets' 'eta' 'eres' 'eries' 'ers' 'ina' 'ines' 'able' 'ls' 'i{o'}' 'itat' 'itats' 'itzar' 'iva' 'ives' 'ivisme' 'ius' 'fer' 'ment' 'amen' 'ament' 'aments' 'ments' 'ot' 'sfera' 'al' 'als' 'era' 'ana' 'iste' 'aire' 'eria' 'esa' 'eses' 'esos' 'or' '{i'}cia' '{i'}cies' 'icis' 'ici' '{i'}ci' '{i'}cis' '{a`}ria' '{a`}ries' 'alla' 'ci{o'}' 'cions' 'n{c,}a' 'nces' '{o'}' 'dor' 'all' 'il' '{i'}stic' 'enc' 'enca' '{i'}s' 'issa' 'issos' '{i'}ssem' '{i'}ssiu' 'issem' 'isseu' '{i'}sseu' '{o'}s' 'osa' 'dora' 'dores' 'dors' 'adura' 'ble' 'bles' '{i'}vol' '{i'}vola' 'd{i'}s' 'egar' 'ejar' 'ificar' 'itar' 'ables' 'adors' 'idores' 'idors' 'adora' 'aci{o'}' 'doras' 'dur' 'dures' 'alleng{u"}es' 'ant' 'ants' 'ancia' 'ancies' 'at{o`}ria' 'at{o`}ries' 'tori' 'toris' 'ats' 'ions' 'ota' 'isam' 'ors' 'ora' 'ores' 'isament' 'bilitat' 'bilitats' 'ivitat' 'ivitats' 'ari' 'aris' 'ionisme' 'ionista' 'ionistes' 'ialista' 'ialistes' 'ialisme' 'ialismes' 'ud' 'uts' 'uds' 'encia' 'encies' '{e`}ncia' '{e`}ncies' '{i"}tat' '{i"}tats' 'atiu' 'atius' 'atives' 'ativa' 'ativitat' 'ativitats' 'ible' 'ibles' 'assa' 'asses' 'assos' 'ent' 'ents' '{i'}ssim' '{i'}ssima' '{i'}ssims' '{i'}ssimes' '{i`}ssem' '{i`}sseu' '{i`}ssin' 'ims' 'ima' 'imes' 'isme' 'ista' 'ismes' 'istes' 'inia' 'inies' '{i'}inia' '{i'}nies' 'ita' 'ites' 'triu' 'trius' 'oses' 'osos' 'ient' 'otes' 'ots' (R1 delete) 'acions' 'ada' 'ades' (R2 delete) 'log{i'}a' 'log{i'}es''logia' 'logies' 'logi' 'logis' 'l{o'}gica' 'l{o'}gics' 'l{o'}giques' (R2 <- 'log') 'ic' 'ica' 'ics' 'iques' (R2 <- 'ic') 'qu{i'}ssim' 'qu{i'}ssims' 'qu{i'}ssimes' 'qu{i'}ssima' (R1 <- 'c') ) ) define verb_suffix as ( [substring] among( 'ador' 'adora' 'adors' 'adores' 're' 'ie' 'ent' 'ents' 'udes' 'ar{a`}' 'eren' 'ar{a'}' 'ar{i'}an' 'ar{i'}as' 'ar{a'}n' 'ar{a'}s' 'ar{i'}ais' 'aria' 'arian' 'arien' 'aries' 'ar{a`}s' 'ar{i'}a' 'ar{e'}is' 'ar{i'}amos' 'aremos' 'ara' 'ar{e'}' 'ar{e'}s' 'er{i'}an' 'er{i'}as' 'er{a'}n' 'er{a'}s' 'er{i'}ais' 'er{i'}a' 'er{e'}is' 'er{i'}amos' 'eremos' 'er{a'}' 'er{e'}' 'er' 'erau' 'erass' 'ir{i'}an' 'ir{i'}as' 'ir{a'}n' 'ir{a'}s' 'ir{i'}ais' 'ir{i'}a' 'ir{e'}is' 'ir{i'}amos' 'iremos' 'ir{a'}' 'ir{e'}' '{i'}rem' '{i'}reu' '{i'}eu' 'ia' 'ies' '{i'}em' '{i`}eu' 'ien' 'at' 'ut' 'uda' 'ava' 'aves' 'avem' '{a'}vem' '{a`}vem' '{a`}veu' '{a'}veu' 'aven' 'au' 'ats' 'asseu' 'esseu' 'eresseu' '{a`}sseu' '{a`}ssem' '{a`}ssim' '{a`}ssiu' 'essen' 'esses' 'assen' 'asses' 'assim' 'assiu' '{e'}ssen' '{e'}sseu' '{e'}ssim' '{e'}ssiu' '{e'}ssem' '{i'}' 'ares' '{a`}rem' '{a`}reu' '{a`}ren' 'ar{i'}em' 'ar{i'}eu' 'areu' 'aren' 'ant' '{i"}m' '{i"}u' '{e'}s' '{i"}en' 'en' 'es' 'em' 'am' 'ams' '{i"}a' '{i"}es' 'dre' 'eix' 'eixer' 'tzar' 'eixes' 'ides' '{i"}des' 'it' '{i"}t' '{i"}da' 'aba' 'ada' 'ades' 'ida' '{i'}a' 'iera' 'ad' 'ed' 'its' 'id' 'ids' 'ase' 'iese' 'aste' 'iste' 'an' 'aban' '{i'}an' 'aran' 'ieran' 'asen' 'iesen' 'aron' 'ieron' 'ado' 'ido' 'iendo' 'i{o'}' 'ar' 'ir' 'as' 'ieu' 'ii' 'io' 'i{a`}' 'ess' 'essin' 'essis' 'ass' 'assin' 'assis' 'essim' '{e`}ssim' '{e`}ssiu' 'abas' 'adas' 'idas' '{i'}as' 'aras' 'ieras' 'ases' 'ieses' '{i'}s' '{a'}is' 'abais' '{i'}ais' 'arais' 'ierais' 'aseis' 'ieseis' 'asteis' 'isteis' 'ados' 'idos' 'amos' '{a'}bamos' '{i'}amos' 'imos' 'ques' '{a'}ramos' 'i{e'}ramos' 'i{e'}semos' '{a'}semos' 'ira' 'iran' 'irem' 'iren' 'ires' 'ireu' 'iria' 'irien' 'iries' 'ir{a`}' 'ir{a`}s' 'ir{e`}' 'ir{i`}em' 'ir{i`}eu' 'isquen' 'iguem' 'igueu' 'esqui' 'esquin' 'esquis' 'eixi' 'eixin' 'eixis' 'eixen' 'eixo' 'isin' 'isis' 'esques' 'sis' 'sin' 'int' 'ir{i'}em' 'ir{i'}eu' 'isc' 'atges' 'esca' 'esquen' 'issen' 'isses' 'issin' 'issis' 'isca' 'issiu' 'issim' '{i"}sc' '{i"}sca' '{i"}ssin' '{i'}ssiu' '{i'}ssim' '{i"}ssis' '{i"}guem' '{i"}gueu' '{i"}ra' '{i"}ren' '{i"}res' '{i"}squen' '{i"}sques' '{i"}ssen' '{i"}sses' '{i"}xo' '{i"}xen' '{i"}xes' '{i"}x' 'ixo' 'ixen' 'ixes' 'ix' 'ixa' 'inin' 'inis' 'ini' 'ineu' 'itza' 'itzi' 'itzeu' 'itzis' 'itzo' 'itz' 'itz{a`}' 'arem' 'in' '{a`}s' 'i{i"}' 'i{i"}n' 'i{i"}s' (R1 delete) 'ando' (R2 delete) ) ) define residual_suffix as ( [substring] among( 'os' 'a' 'o' '{a'}' '{a`}' '{i'}' '{o'}' 'e' '{e'}' 'eu' 'iu' 'is' 'i' 'ir' 's' '{i`}' 'itz' '{i"}' '{i"}n' '{i"}s' 'it' (R1 delete) 'iqu' (R1 <- 'ic') ) ) ) define stem as ( do mark_regions backwards ( do attached_pronoun do ( standard_suffix or verb_suffix ) do residual_suffix ) do cleaning ) /* First works 2010/07/19 First Gramatical Reviews: http://ca.wikipedia.org/wiki/Gram%C3%A0tica_catalana Sufix list: http://wapedia.mobi/ca/Llista_de_sufixos Irregular Verbs: http://ca.wikipedia.org/wiki/Flexi%C3%B3_verbal_del_catal%C3%A0 */