Finding homonyms in a (Latin) treebank

Homonyms and homographs (H & H) in a language are a good thing to master — a lot of confusion goes away once we have understood the differences, and our grasp of the language is significantly improved.

We don't want to run away from the H & H — we want to tackle them at full speed. That means that, if we read a text, we could pick from it a list of phrases with H & H, read them, and see which meaning is employed where.

To do this, we need:

• a list of homonyms and homographs, such as the one Chris Francese and David Kovacs have compiled for Latin
• a text
• tools to find phrases with H & H and collect them in one place

Our task can be done in many ways, including purely "manual" ones. But we would like to use the Perseus Latin Treebank files to find more homonyms and homographs, and to extract phrases from these treebank files as well.

Finding H & H turns out to be a computationally demanding task. On some 50,000+ words my computer chokes and never finishes; 10,000 words is still too much for it. But sets of some 2,500 words are about right, don't take all night to finish.

To an XML file like this:

<uniq>
<w form="vulgo" postag="d--------"/>
<w form="vulgo" postag="d--------"/>
<w form="vulgus" postag="n-s---mn-"/>
<w form="vulnera" postag="n-p---na-"/>
<w form="vulnera" postag="n-p---na-"/>
<w form="vulnera" postag="n-p---na-"/>
<w form="vulnerat" postag="v3spia---"/>
<w form="vulneratum" postag="t-srppma-"/>
<w form="vulnere" postag="n-s---nb-"/>
<w form="vulneribus" postag="n-p---nb-"/>
<w form="vulneribus" postag="n-p---nb-"/>
<w form="vulnus" postag="n-s---nn-"/>
<w form="vulpes" postag="n-p---fn-"/>
<w form="vult" postag="v3spia---"/>
<w form="vult" postag="v3spia---"/>
<w form="vult" postag="v3spia---"/>
<w form="vult" postag="v3spia---"/>
<w form="vultis" postag="v2ppia---"/>
<w form="vultu" postag="n-s---mb-"/>
<w form="vultu" postag="n-s---mb-"/>
<w form="vultum" postag="n-s---ma-"/>
<w form="vultum" postag="n-s---ma-"/>
<w form="vultum" postag="n-s---ma-"/>
<w form="vultus" postag="n-p---ma-"/>
<w form="vultus" postag="n-p---ma-"/>
<w form="vultus" postag="n-p---ma-"/>
<w form="vultus" postag="n-p---ma-"/>
<w form="vultus" postag="n-s---mg-"/>
<w form="vultus" postag="n-s---mn-"/>
</uniq>

We apply the following XQuery (using BaseX, in my case):

element uniq
{ let $a := //*:w
for $l in distinct-values($a/@form),
$f in distinct-values($a[@form=$l]/@postag)
return

element w {
attribute form { $l },
attribute postag { $f }
}
}

Result:

<uniq>
<w form="vulgo" postag="d--------"/>
<w form="vulgus" postag="n-s---mn-"/>
<w form="vulnera" postag="n-p---na-"/>
<w form="vulnerat" postag="v3spia---"/>
<w form="vulneratum" postag="t-srppma-"/>
<w form="vulnere" postag="n-s---nb-"/>
<w form="vulneribus" postag="n-p---nb-"/>
<w form="vulnus" postag="n-s---nn-"/>
<w form="vulpes" postag="n-p---fn-"/>
<w form="vult" postag="v3spia---"/>
<w form="vultis" postag="v2ppia---"/>
<w form="vultu" postag="n-s---mb-"/>
<w form="vultum" postag="n-s---ma-"/>
<w form="vultus" postag="n-p---ma-"/>
<w form="vultus" postag="n-s---mg-"/>
<w form="vultus" postag="n-s---mn-"/>
</uniq>

The most interesting cases are those in which @postag attribute begins with a different value for the same @form, e. g:

<w form="vivis" postag="a-p---mb-"/>
<w form="vivis" postag="a-p---md-"/>
<w form="vivis" postag="n-p---mb-"/>
<w form="vivis" postag="v2spia---"/>

Then we look for "vivis" e. g. in the Croatiae auctores Latini text collection.

How to write a BaseX XQuery with RESTXQ

Caution: technical stuff. Over holidays we managed to put up a BaseX XML database instance as a web application on several machines. But how to execute an XQuery there? A simple approach: use an already provided BaseX REST interface. However, the BaseX team seems more interested in RESTXQ, "a set of XQuery 3.0 Annotations and a small set of functions to enable XQuery to provide RESTful services, thus enabling Web Application development in XQuery" (from the unofficial RESTXQ draft). BaseX supports RESTXQ very well, but the existing documentation is somewhat sparse for a non-programmer like me. Conspicuously absent is an example of a "standard" XQuery search directed at a database (or, in XQuery parlance, a collection). This will be provided here.

The task. A BaseX war instance is deployed on a Jetty server (on my machine, which runs Debian Mint, in /var/lib/jetty8/webapps), accessible on the address http://localhost:8080/BaseX772. A database collection crobib was created and populated with several TEI XML files (with FRBR-structured bibliographical data on Croatian Latin authors, works, and manifestations). We want to execute the following query over the internet, finding the text under tei:persName element as child of all eleventh tei:person elements in the collection:

declare namespace tei = "http://www.tei-c.org/ns/1.0";
for $i in collection("crobib")//tei:person[11]
return element p { $i/tei:persName//text() }


The solution. An .xq script should be written and placed (in our case) under the root of the BaseX war archive. If all goes well, it is found and read by Jetty and BaseX when the server is restarted. This is the script (cbxq.xq). Note how the resulting sequence has to be wrapped in a div element:

import module namespace rest = "http://exquery.org/ns/restxq";
declare namespace page = 'http://basex.org/examples/web-page';
declare namespace tei = "http://www.tei-c.org/ns/1.0";
declare %rest:GET %rest:POST %rest:path("person")
function page:person() {
element div {
for $i in collection("crobib")//tei:person[11]
return ( element p { $i/tei:persName//text() } )
}
};
return

The script is requested over the following address: http://localhost:8080/BaseX772/person.

Going further. We want to search not just for eleventh tei:person element, but for whichever we want. The number of the element should be turned into a variable holding an integer, and the variable will be given as part of the HTML address request. The script now looks like this:

import module namespace rest = "http://exquery.org/ns/restxq";
declare namespace page = "http://basex.org/examples/web-page";
declare namespace tei = "http://www.tei-c.org/ns/1.0";
declare %rest:GET %rest:POST %rest:path("person")
%rest:query-param("var", "{$var}")
function page:person($var as xs:integer) {
element div {
for $i in collection("crobib")//tei:person[$var]
return ( element p { $i/tei:persName//text() } )
}
};
return

We had to declare query parameter var: %rest:query-param("var", "{$var}") and to instruct the function page:person to expect it: function page:person($var as xs:integer).

The script is requested with a call such as this (querying the hundredth tei:person): http://localhost:8080/BaseX772/person?var=100.