Miloš Miljković Miloš Miljković - 2 months ago 9
Javascript Question

Greek language support for lunr.js

Is it possible to implement this greek stemmer in lunr.js? lunr.js on gitter wasn't much of help. Generally I found the information on implementing a new language support very poor.

P.S. I'm familiar with only some basics of javascript and am still in learning process.

P.P.S. I am now trying to replace the original english stemmer with a greek one, my code is below but it's not working, the greek stemmer is based on the Porter algorithm so it is very similar, could you examine the code below?

lunr.stemmer = (function(){

// GREEK STEMMER

step1list = new Array();
step1list["ΦΑΓΙΑ"]="ΦΑ";
step1list["ΦΑΓΙΟΥ"]="ΦΑ";
step1list["ΦΑΓΙΩΝ"]="ΦΑ";
step1list["ΣΚΑΓΙΑ"]="ΣΚΑ";
step1list["ΣΚΑΓΙΟΥ"]="ΣΚΑ";
step1list["ΣΚΑΓΙΩΝ"]="ΣΚΑ";
step1list["ΟΛΟΓΙΟΥ"]="ΟΛΟ";
step1list["ΟΛΟΓΙΑ"]="ΟΛΟ";
step1list["ΟΛΟΓΙΩΝ"]="ΟΛΟ";
step1list["ΣΟΓΙΟΥ"]="ΣΟ";
step1list["ΣΟΓΙΑ"]="ΣΟ";
step1list["ΣΟΓΙΩΝ"]="ΣΟ";
step1list["ΤΑΤΟΓΙΑ"]="ΤΑΤΟ";
step1list["ΤΑΤΟΓΙΟΥ"]="ΤΑΤΟ";
step1list["ΤΑΤΟΓΙΩΝ"]="ΤΑΤΟ";
step1list["ΚΡΕΑΣ"]="ΚΡΕ";
step1list["ΚΡΕΑΤΟΣ"]="ΚΡΕ";
step1list["ΚΡΕΑΤΑ"]="ΚΡΕ";
step1list["ΚΡΕΑΤΩΝ"]="ΚΡΕ";
step1list["ΠΕΡΑΣ"]="ΠΕΡ";
step1list["ΠΕΡΑΤΟΣ"]="ΠΕΡ";
step1list["ΠΕΡΑΤΑ"]="ΠΕΡ";
step1list["ΠΕΡΑΤΩΝ"]="ΠΕΡ";
step1list["ΤΕΡΑΣ"]="ΤΕΡ";
step1list["ΤΕΡΑΤΟΣ"]="ΤΕΡ";
step1list["ΤΕΡΑΤΑ"]="ΤΕΡ";
step1list["ΤΕΡΑΤΩΝ"]="ΤΕΡ";
step1list["ΦΩΣ"]="ΦΩ";
step1list["ΦΩΤΟΣ"]="ΦΩ";
step1list["ΦΩΤΑ"]="ΦΩ";
step1list["ΦΩΤΩΝ"]="ΦΩ";
step1list["ΚΑΘΕΣΤΩΣ"]="ΚΑΘΕΣΤ";
step1list["ΚΑΘΕΣΤΩΤΟΣ"]="ΚΑΘΕΣΤ";
step1list["ΚΑΘΕΣΤΩΤΑ"]="ΚΑΘΕΣΤ";
step1list["ΚΑΘΕΣΤΩΤΩΝ"]="ΚΑΘΕΣΤ";
step1list["ΓΕΓΟΝΟΣ"]="ΓΕΓΟΝ";
step1list["ΓΕΓΟΝΟΤΟΣ"]="ΓΕΓΟΝ";
step1list["ΓΕΓΟΝΟΤΑ"]="ΓΕΓΟΝ";
step1list["ΓΕΓΟΝΟΤΩΝ"]="ΓΕΓΟΝ";


v = "[ΑΕΗΙΟΥΩ]"; // vowel
v2 = "[ΑΕΗΙΟΩ]" //vowel without Y

var porterStemmer = function porterStemmer(w) {
var stem;
var suffix;
var firstch;
var origword = w;
test1 = new Boolean(true);

if (w.length < 4) { return w; }

var re;
var re2;
var re3;
var re4;


//Step1

re = /(.*)(ΦΑΓΙΑ|ΦΑΓΙΟΥ|ΦΑΓΙΩΝ|ΣΚΑΓΙΑ|ΣΚΑΓΙΟΥ|ΣΚΑΓΙΩΝ|ΟΛΟΓΙΟΥ|ΟΛΟΓΙΑ|ΟΛΟΓΙΩΝ|ΣΟΓΙΟΥ|ΣΟΓΙΑ|ΣΟΓΙΩΝ|ΤΑΤΟΓΙΑ|ΤΑΤΟΓΙΟΥ|ΤΑΤΟΓΙΩΝ|ΚΡΕΑΣ|ΚΡΕΑΤΟΣ|ΚΡΕΑΤΑ|ΚΡΕΑΤΩΝ|ΠΕΡΑΣ|ΠΕΡΑΤΟΣ|ΠΕΡΑΤΑ|ΠΕΡΑΤΩΝ|ΤΕΡΑΣ|ΤΕΡΑΤΟΣ|ΤΕΡΑΤΑ|ΤΕΡΑΤΩΝ|ΦΩΣ|ΦΩΤΟΣ|ΦΩΤΑ|ΦΩΤΩΝ|ΚΑΘΕΣΤΩΣ|ΚΑΘΕΣΤΩΤΟΣ|ΚΑΘΕΣΤΩΤΑ|ΚΑΘΕΣΤΩΤΩΝ|ΓΕΓΟΝΟΣ|ΓΕΓΟΝΟΤΟΣ|ΓΕΓΟΝΟΤΑ|ΓΕΓΟΝΟΤΩΝ)$/;

if (re.test(w)) {
var fp = re.exec(w);
stem = fp[1];
suffix = fp[2];
w = stem + step1list[suffix];
test1 = false;
}



// Step 2a
re = /^(.+?)(ΑΔΕΣ|ΑΔΩΝ)$/;


if (re.test(w)) {
var fp = re.exec(w);
stem = fp[1];
w = stem;

reg1 = /(ΟΚ|ΜΑΜ|ΜΑΝ|ΜΠΑΜΠ|ΠΑΤΕΡ|ΓΙΑΓΙ|ΝΤΑΝΤ|ΚΥΡ|ΘΕΙ|ΠΕΘΕΡ)$/;

if (!(reg1.test(w))) {w = w + "ΑΔ";}

}

//Step 2b
re2 = /^(.+?)(ΕΔΕΣ|ΕΔΩΝ)$/;

if (re2.test(w)) {
var fp = re2.exec(w);
stem = fp[1];
w = stem;

exept2 = /(ΟΠ|ΙΠ|ΕΜΠ|ΥΠ|ΓΗΠ|ΔΑΠ|ΚΡΑΣΠ|ΜΙΛ)$/;

if (exept2.test(w)) {w = w + "ΕΔ";}

}

//Step 2c
re3 = /^(.+?)(ΟΥΔΕΣ|ΟΥΔΩΝ)$/;

if (re3.test(w)) {
var fp = re3.exec(w);
stem = fp[1];
w = stem;

exept3 = /(ΑΡΚ|ΚΑΛΙΑΚ|ΠΕΤΑΛ|ΛΙΧ|ΠΛΕΞ|ΣΚ|Σ|ΦΛ|ΦΡ|ΒΕΛ|ΛΟΥΛ|ΧΝ|ΣΠ|ΤΡΑΓ|ΦΕ)$/;

if (exept3.test(w)) {w = w + "ΟΥΔ";}

}


//Step 2d
re4 = /^(.+?)(ΕΩΣ|ΕΩΝ)$/;

if (re4.test(w)) {
var fp = re4.exec(w);
stem = fp[1];
w = stem;
test1 = false;

exept4 = /^(Θ|Δ|ΕΛ|ΓΑΛ|Ν|Π|ΙΔ|ΠΑΡ)$/;

if (exept4.test(w)) {
w = w + "Ε";

}
}

//Step 3
re = /^(.+?)(ΙΑ|ΙΟΥ|ΙΩΝ)$/;

if (re.test(w)) {
var fp = re.exec(w);
stem = fp[1];
w = stem;
re2 = new RegExp (v+"$");
test1 = false;

if (re2.test(w)) {
w = stem + "Ι";
}

}


//Step 4
re = /^(.+?)(ΙΚΑ|ΙΚΟ|ΙΚΟΥ|ΙΚΩΝ)$/;

if (re.test(w)) {
var fp = re.exec(w);
stem = fp[1];
w = stem;
test1 = false;

re2 = new RegExp (v+"$");
exept5 = /^(ΑΛ|ΑΔ|ΕΝΔ|ΑΜΑΝ|ΑΜΜΟΧΑΛ|ΗΘ|ΑΝΗΘ|ΑΝΤΙΔ|ΦΥΣ|ΒΡΩΜ|ΓΕΡ|ΕΞΩΔ|ΚΑΛΠ|ΚΑΛΛΙΝ|ΚΑΤΑΔ|ΜΟΥΛ|ΜΠΑΝ|ΜΠΑΓΙΑΤ|ΜΠΟΛ|ΜΠΟΣ|ΝΙΤ|ΞΙΚ|ΣΥΝΟΜΗΛ|ΠΕΤΣ|ΠΙΤΣ|ΠΙΚΑΝΤ|ΠΛΙΑΤΣ|ΠΟΣΤΕΛΝ|ΠΡΩΤΟΔ|ΣΕΡΤ|ΣΥΝΑΔ|ΤΣΑΜ|ΥΠΟΔ|ΦΙΛΟΝ|ΦΥΛΟΔ|ΧΑΣ)$/;

if ((exept5.test(w)) || (re2.test(w))){
w = w + "ΙΚ";
}
}

//step 5a
re = /^(.+?)(ΑΜΕ)$/;
re2 = /^(.+?)(ΑΓΑΜΕ|ΗΣΑΜΕ|ΟΥΣΑΜΕ|ΗΚΑΜΕ|ΗΘΗΚΑΜΕ)$/;
if (w == "ΑΓΑΜΕ"){w = "ΑΓΑΜ";}

if (re2.test(w)) {
var fp = re2.exec(w);
stem = fp[1];
w = stem;
test1 = false;
}



if (re.test(w)) {
var fp = re.exec(w);
stem = fp[1];
w = stem;
test1 = false;

exept6 = /^(ΑΝΑΠ|ΑΠΟΘ|ΑΠΟΚ|ΑΠΟΣΤ|ΒΟΥΒ|ΞΕΘ|ΟΥΛ|ΠΕΘ|ΠΙΚΡ|ΠΟΤ|ΣΙΧ|Χ)$/;

if (exept6.test(w)){
w = w + "ΑΜ";
}
}


//Step 5b
re2 = /^(.+?)(ΑΝΕ)$/;
re3 = /^(.+?)(ΑΓΑΝΕ|ΗΣΑΝΕ|ΟΥΣΑΝΕ|ΙΟΝΤΑΝΕ|ΙΟΤΑΝΕ|ΙΟΥΝΤΑΝΕ|ΟΝΤΑΝΕ|ΟΤΑΝΕ|ΟΥΝΤΑΝΕ|ΗΚΑΝΕ|ΗΘΗΚΑΝΕ)$/;

if (re3.test(w)) {
var fp = re3.exec(w);
stem = fp[1];
w = stem;
test1 = false;

re3 = /^(ΤΡ|ΤΣ)$/;

if (re3.test(w)) {
w = w + "ΑΓΑΝ";
}
}


if (re2.test(w)) {
var fp = re2.exec(w);
stem = fp[1];
w = stem;
test1 = false;

re2 = new RegExp (v2 +"$");
exept7 = /^(ΒΕΤΕΡ|ΒΟΥΛΚ|ΒΡΑΧΜ|Γ|ΔΡΑΔΟΥΜ|Θ|ΚΑΛΠΟΥΖ|ΚΑΣΤΕΛ|ΚΟΡΜΟΡ|ΛΑΟΠΛ|ΜΩΑΜΕΘ|Μ|ΜΟΥΣΟΥΛΜ|Ν|ΟΥΛ|Π|ΠΕΛΕΚ|ΠΛ|ΠΟΛΙΣ|ΠΟΡΤΟΛ|ΣΑΡΑΚΑΤΣ|ΣΟΥΛΤ|ΤΣΑΡΛΑΤ|ΟΡΦ|ΤΣΙΓΓ|ΤΣΟΠ|ΦΩΤΟΣΤΕΦ|Χ|ΨΥΧΟΠΛ|ΑΓ|ΟΡΦ|ΓΑΛ|ΓΕΡ|ΔΕΚ|ΔΙΠΛ|ΑΜΕΡΙΚΑΝ|ΟΥΡ|ΠΙΘ|ΠΟΥΡΙΤ|Σ|ΖΩΝΤ|ΙΚ|ΚΑΣΤ|ΚΟΠ|ΛΙΧ|ΛΟΥΘΗΡ|ΜΑΙΝΤ|ΜΕΛ|ΣΙΓ|ΣΠ|ΣΤΕΓ|ΤΡΑΓ|ΤΣΑΓ|Φ|ΕΡ|ΑΔΑΠ|ΑΘΙΓΓ|ΑΜΗΧ|ΑΝΙΚ|ΑΝΟΡΓ|ΑΠΗΓ|ΑΠΙΘ|ΑΤΣΙΓΓ|ΒΑΣ|ΒΑΣΚ|ΒΑΘΥΓΑΛ|ΒΙΟΜΗΧ|ΒΡΑΧΥΚ|ΔΙΑΤ|ΔΙΑΦ|ΕΝΟΡΓ|ΘΥΣ|ΚΑΠΝΟΒΙΟΜΗΧ|ΚΑΤΑΓΑΛ|ΚΛΙΒ|ΚΟΙΛΑΡΦ|ΛΙΒ|ΜΕΓΛΟΒΙΟΜΗΧ|ΜΙΚΡΟΒΙΟΜΗΧ|ΝΤΑΒ|ΞΗΡΟΚΛΙΒ|ΟΛΙΓΟΔΑΜ|ΟΛΟΓΑΛ|ΠΕΝΤΑΡΦ|ΠΕΡΗΦ|ΠΕΡΙΤΡ|ΠΛΑΤ|ΠΟΛΥΔΑΠ|ΠΟΛΥΜΗΧ|ΣΤΕΦ|ΤΑΒ|ΤΕΤ|ΥΠΕΡΗΦ|ΥΠΟΚΟΠ|ΧΑΜΗΛΟΔΑΠ|ΨΗΛΟΤΑΒ)$/;

if ((re2.test(w)) || (exept7.test(w))){
w = w + "ΑΝ";
}
}


//Step 5c
re3 = /^(.+?)(ΕΤΕ)$/;
re4 = /^(.+?)(ΗΣΕΤΕ)$/;

if (re4.test(w)) {
var fp = re4.exec(w);
stem = fp[1];
w = stem;
test1 = false;
}




if (re3.test(w)) {
var fp = re3.exec(w);
stem = fp[1];
w = stem;
test1 = false;

re3 = new RegExp (v2 +"$");
exept8 = /(ΟΔ|ΑΙΡ|ΦΟΡ|ΤΑΘ|ΔΙΑΘ|ΣΧ|ΕΝΔ|ΕΥΡ|ΤΙΘ|ΥΠΕΡΘ|ΡΑΘ|ΕΝΘ|ΡΟΘ|ΣΘ|ΠΥΡ|ΑΙΝ|ΣΥΝΔ|ΣΥΝ|ΣΥΝΘ|ΧΩΡ|ΠΟΝ|ΒΡ|ΚΑΘ|ΕΥΘ|ΕΚΘ|ΝΕΤ|ΡΟΝ|ΑΡΚ|ΒΑΡ|ΒΟΛ|ΩΦΕΛ)$/;
exept9 = /^(ΑΒΑΡ|ΒΕΝ|ΕΝΑΡ|ΑΒΡ|ΑΔ|ΑΘ|ΑΝ|ΑΠΛ|ΒΑΡΟΝ|ΝΤΡ|ΣΚ|ΚΟΠ|ΜΠΟΡ|ΝΙΦ|ΠΑΓ|ΠΑΡΑΚΑΛ|ΣΕΡΠ|ΣΚΕΛ|ΣΥΡΦ|ΤΟΚ|Υ|Δ|ΕΜ|ΘΑΡΡ|Θ)$/;

if ((re3.test(w)) || (exept8.test(w)) || (exept9.test(w))){
w = w + "ΕΤ";
}
}

//Step 5d
re = /^(.+?)(ΟΝΤΑΣ|ΩΝΤΑΣ)$/;

if (re.test(w)) {
var fp = re.exec(w);
stem = fp[1];
w = stem;
test1 = false;

exept10 = /^(ΑΡΧ)$/;
exept11 = /(ΚΡΕ)$/;
if (exept10.test(w)){
w = w + "ΟΝΤ";
}
if (exept11.test(w)){
w = w + "ΩΝΤ";
}
}

//Step 5e
re = /^(.+?)(ΟΜΑΣΤΕ|ΙΟΜΑΣΤΕ)$/;

if (re.test(w)) {
var fp = re.exec(w);
stem = fp[1];
w = stem;
test1 = false;

exept11 = /^(ΟΝ)$/;

if (exept11.test(w)){
w = w + "ΟΜΑΣΤ";
}
}

//Step 5f
re = /^(.+?)(ΕΣΤΕ)$/;
re2 = /^(.+?)(ΙΕΣΤΕ)$/;

if (re2.test(w)) {
var fp = re2.exec(w);
stem = fp[1];
w = stem;
test1 = false;

re2 = /^(Π|ΑΠ|ΣΥΜΠ|ΑΣΥΜΠ|ΑΚΑΤΑΠ|ΑΜΕΤΑΜΦ)$/;

if (re2.test(w)){
w = w + "ΙΕΣΤ";
}
}

if (re.test(w)) {
var fp = re.exec(w);
stem = fp[1];
w = stem;
test1 = false;

exept12 = /^(ΑΛ|ΑΡ|ΕΚΤΕΛ|Ζ|Μ|Ξ|ΠΑΡΑΚΑΛ|ΑΡ|ΠΡΟ|ΝΙΣ)$/;

if (exept12.test(w)){
w = w + "ΕΣΤ";
}
}


//Step 5g
re = /^(.+?)(ΗΚΑ|ΗΚΕΣ|ΗΚΕ)$/;
re2 = /^(.+?)(ΗΘΗΚΑ|ΗΘΗΚΕΣ|ΗΘΗΚΕ)$/;

if (re2.test(w)){
var fp = re2.exec(w);
stem = fp[1];
w = stem;
test1 = false;
}

if (re.test(w)) {
var fp = re.exec(w);
stem = fp[1];
w = stem;
test1 = false;

exept13 = /(ΣΚΩΛ|ΣΚΟΥΛ|ΝΑΡΘ|ΣΦ|ΟΘ|ΠΙΘ)$/;
exept14 = /^(ΔΙΑΘ|Θ|ΠΑΡΑΚΑΤΑΘ|ΠΡΟΣΘ|ΣΥΝΘ|)$/;

if ((exept13.test(w)) || (exept14.test(w))){
w = w + "ΗΚ";
}
}


//Step 5h
re = /^(.+?)(ΟΥΣΑ|ΟΥΣΕΣ|ΟΥΣΕ)$/;

if (re.test(w)) {
var fp = re.exec(w);
stem = fp[1];
w = stem;
test1 = false;

exept15 = /^(ΦΑΡΜΑΚ|ΧΑΔ|ΑΓΚ|ΑΝΑΡΡ|ΒΡΟΜ|ΕΚΛΙΠ|ΛΑΜΠΙΔ|ΛΕΧ|Μ|ΠΑΤ|Ρ|Λ|ΜΕΔ|ΜΕΣΑΖ|ΥΠΟΤΕΙΝ|ΑΜ|ΑΙΘ|ΑΝΗΚ|ΔΕΣΠΟΖ|ΕΝΔΙΑΦΕΡ|ΔΕ|ΔΕΥΤΕΡΕΥ|ΚΑΘΑΡΕΥ|ΠΛΕ|ΤΣΑ)$/;
exept16 = /(ΠΟΔΑΡ|ΒΛΕΠ|ΠΑΝΤΑΧ|ΦΡΥΔ|ΜΑΝΤΙΛ|ΜΑΛΛ|ΚΥΜΑΤ|ΛΑΧ|ΛΗΓ|ΦΑΓ|ΟΜ|ΠΡΩΤ)$/;

if ((exept15.test(w)) || (exept16.test(w))){
w = w + "ΟΥΣ";
}
}


//Step 5i
re = /^(.+?)(ΑΓΑ|ΑΓΕΣ|ΑΓΕ)$/;

if (re.test(w)) {
var fp = re.exec(w);
stem = fp[1];
w = stem;
test1 = false;

exept17 = /^(ΨΟΦ|ΝΑΥΛΟΧ)$/;
exept20 = /(ΚΟΛΛ)$/;
exept18 = /^(ΑΒΑΣΤ|ΠΟΛΥΦ|ΑΔΗΦ|ΠΑΜΦ|Ρ|ΑΣΠ|ΑΦ|ΑΜΑΛ|ΑΜΑΛΛΙ|ΑΝΥΣΤ|ΑΠΕΡ|ΑΣΠΑΡ|ΑΧΑΡ|ΔΕΡΒΕΝ|ΔΡΟΣΟΠ|ΞΕΦ|ΝΕΟΠ|ΝΟΜΟΤ|ΟΛΟΠ|ΟΜΟΤ|ΠΡΟΣΤ|ΠΡΟΣΩΠΟΠ|ΣΥΜΠ|ΣΥΝΤ|Τ|ΥΠΟΤ|ΧΑΡ|ΑΕΙΠ|ΑΙΜΟΣΤ|ΑΝΥΠ|ΑΠΟΤ|ΑΡΤΙΠ|ΔΙΑΤ|ΕΝ|ΕΠΙΤ|ΚΡΟΚΑΛΟΠ|ΣΙΔΗΡΟΠ|Λ|ΝΑΥ|ΟΥΛΑΜ|ΟΥΡ|Π|ΤΡ|Μ)$/;
exept19 = /(ΟΦ|ΠΕΛ|ΧΟΡΤ|ΛΛ|ΣΦ|ΡΠ|ΦΡ|ΠΡ|ΛΟΧ|ΣΜΗΝ)$/;

if (((exept18.test(w)) || (exept19.test(w))) && !((exept17.test(w)) || (exept20.test(w)))){
w = w + "ΑΓ";
}
}


//Step 5j
re = /^(.+?)(ΗΣΕ|ΗΣΟΥ|ΗΣΑ)$/;

if (re.test(w)) {
var fp = re.exec(w);
stem = fp[1];
w = stem;
test1 = false;

exept21 = /^(Ν|ΧΕΡΣΟΝ|ΔΩΔΕΚΑΝ|ΕΡΗΜΟΝ|ΜΕΓΑΛΟΝ|ΕΠΤΑΝ)$/;

if (exept21.test(w)){
w = w + "ΗΣ";
}
}

//Step 5k
re = /^(.+?)(ΗΣΤΕ)$/;

if (re.test(w)) {
var fp = re.exec(w);
stem = fp[1];
w = stem;
test1 = false;

exept22 = /^(ΑΣΒ|ΣΒ|ΑΧΡ|ΧΡ|ΑΠΛ|ΑΕΙΜΝ|ΔΥΣΧΡ|ΕΥΧΡ|ΚΟΙΝΟΧΡ|ΠΑΛΙΜΨ)$/;

if (exept22.test(w)){
w = w + "ΗΣΤ";
}
}

//Step 5l
re = /^(.+?)(ΟΥΝΕ|ΗΣΟΥΝΕ|ΗΘΟΥΝΕ)$/;

if (re.test(w)) {
var fp = re.exec(w);
stem = fp[1];
w = stem;
test1 = false;

exept23 = /^(Ν|Ρ|ΣΠΙ|ΣΤΡΑΒΟΜΟΥΤΣ|ΚΑΚΟΜΟΥΤΣ|ΕΞΩΝ)$/;

if (exept23.test(w)){
w = w + "ΟΥΝ";
}
}

//Step 5l
re = /^(.+?)(ΟΥΜΕ|ΗΣΟΥΜΕ|ΗΘΟΥΜΕ)$/;

if (re.test(w)) {
var fp = re.exec(w);
stem = fp[1];
w = stem;
test1 = false;

exept24 = /^(ΠΑΡΑΣΟΥΣ|Φ|Χ|ΩΡΙΟΠΛ|ΑΖ|ΑΛΛΟΣΟΥΣ|ΑΣΟΥΣ)$/;

if (exept24.test(w)){
w = w + "ΟΥΜ";
}
}



// Step 6

re=/^(.+?)(ΜΑΤΑ|ΜΑΤΩΝ|ΜΑΤΟΣ)$/;
re2 = /^(.+?)(Α|ΑΓΑΤΕ|ΑΓΑΝ|ΑΕΙ|ΑΜΑΙ|ΑΝ|ΑΣ|ΑΣΑΙ|ΑΤΑΙ|ΑΩ|Ε|ΕΙ|ΕΙΣ|ΕΙΤΕ|ΕΣΑΙ|ΕΣ|ΕΤΑΙ|Ι|ΙΕΜΑΙ|ΙΕΜΑΣΤΕ|ΙΕΤΑΙ|ΙΕΣΑΙ|ΙΕΣΑΣΤΕ|ΙΟΜΑΣΤΑΝ|ΙΟΜΟΥΝ|ΙΟΜΟΥΝΑ|ΙΟΝΤΑΝ|ΙΟΝΤΟΥΣΑΝ|ΙΟΣΑΣΤΑΝ|ΙΟΣΑΣΤΕ|ΙΟΣΟΥΝ|ΙΟΣΟΥΝΑ|ΙΟΤΑΝ|ΙΟΥΜΑ|ΙΟΥΜΑΣΤΕ|ΙΟΥΝΤΑΙ|ΙΟΥΝΤΑΝ|Η|ΗΔΕΣ|ΗΔΩΝ|ΗΘΕΙ|ΗΘΕΙΣ|ΗΘΕΙΤΕ|ΗΘΗΚΑΤΕ|ΗΘΗΚΑΝ|ΗΘΟΥΝ|ΗΘΩ|ΗΚΑΤΕ|ΗΚΑΝ|ΗΣ|ΗΣΑΝ|ΗΣΑΤΕ|ΗΣΕΙ|ΗΣΕΣ|ΗΣΟΥΝ|ΗΣΩ|Ο|ΟΙ|ΟΜΑΙ|ΟΜΑΣΤΑΝ|ΟΜΟΥΝ|ΟΜΟΥΝΑ|ΟΝΤΑΙ|ΟΝΤΑΝ|ΟΝΤΟΥΣΑΝ|ΟΣ|ΟΣΑΣΤΑΝ|ΟΣΑΣΤΕ|ΟΣΟΥΝ|ΟΣΟΥΝΑ|ΟΤΑΝ|ΟΥ|ΟΥΜΑΙ|ΟΥΜΑΣΤΕ|ΟΥΝ|ΟΥΝΤΑΙ|ΟΥΝΤΑΝ|ΟΥΣ|ΟΥΣΑΝ|ΟΥΣΑΤΕ|Υ|ΥΣ|Ω|ΩΝ)$/;

if (re.test(w)) {
var fp = re.exec(w);
stem = fp[1];
w = stem + "ΜΑ";
}

if ((re2.test(w))&&(test1)){
var fp = re2.exec(w);
stem = fp[1];
w = stem;

}

// Step 7 (ΠΑΡΑΘΕΤΙΚΑ)

re = /^(.+?)(ΕΣΤΕΡ|ΕΣΤΑΤ|ΟΤΕΡ|ΟΤΑΤ|ΥΤΕΡ|ΥΤΑΤ|ΩΤΕΡ|ΩΤΑΤ)$/;

if (re.test(w)){
var fp = re.exec(w);
stem = fp[1];
w = stem;
}

return w;

};

return porterStemmer;
})();

lunr.Pipeline.registerFunction(lunr.stemmer, 'stemmer')

Answer

In lunr a stemmer is implemented as a pipeline function. A pipeline function is executed against each word in a document when indexing the document, and each word in a search query when searching.

For a function to work in a pipeline it has to implement a very simple interface. It needs to accept a single string as input, and it must respond with a string as its output.

So a very simple (and useless) pipeline function would look like the following:

var simplePipelineFunction = function (word) {
  return word
}

To actually make use of this pipeline function we need to do two things:

  1. Register it as a pipeline function, this allows lunr to correctly serialise and deserialise your pipeline.
  2. Add it to your indexes pipeline.

That would look something like this:

// registering our pipeline function with the name 'simplePipelineFunction'
lunr.Pipeline.registerFunction(simplePipelineFunction, 'simplePipelineFunction')

var idx = lunr(function () {
  // adding the pipeline function to our indexes pipeline
  // when defining the pipeline
  this.pipeline.add(simplePipelineFunction)
})

Now, you can take the above, and swap out the implementation of our pipeline function. So, instead of just returning the word unchanged, it could use the greek stemmer you have found to stem the word, maybe like this:

var myGreekStemmer = function (word) {
  // I don't know how to use the greek stemmer, but I think
  // its safe to assume it won't be that different than this
  return greekStem(word)
}

Adapting lunr to work with a language other than English requires more than just adding your stemmer though. The default language of lunr is English, and so, by default, it includes pipeline functions that are specialised for English. English and Greek are different enough that you will probably run into issues trying to index Greek words with the English defaults, so we need to do the following:

  1. Replace the default stemmer with our language specific stemmer
  2. Remove the default trimmer which doesn't play so nice with non-latin characters
  3. Replace/remove the default stop word filter, its unlikely to be much use on a language other than English.

The trimmer and stop word filter are implemented as pipeline functions, so implementing language specific ones would be similar for the stemmer.

So, to set up lunr for Greek you would have this:

var idx = lunr(function () {
  this.pipeline.replace(lunr.stemmer, greekStemmer)
  this.pipeline.replace(lunr.trimmer, greekTrimmer) // Can remove if there is no greekTrimmer
  this.pipeline.replace(lunr.stopWordFilter, greekStopWordFilter) // Again, just remove if you don't have/need a Greek stop word filter.

  // define the index as normal
  this.ref('id')
  this.field('title')
  this.field('body')
})

For some more inspiration you can take a look at the excellent lunr-languages project, it has many examples of creating language extensions for lunr. You could even submit one for Greek!

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