Constituent Parser

The constituent parser wraps several other constituent parsers into a component that parses the 6 main opener languages. Each language uses it's own parser and core. For more information on the specific languages, please check the individual cores.

Confused by some terminology?

This software is part of a larger collection of natural language processing tools known as "the OpeNER project". You can find more information about the project at the OpeNER portal. There you can also find references to terms like KAF (an XML standard to represent linguistic annotations in texts), component, cores, scenario's and pipelines.

Quick Use Example

Installing the constituent-parser can be done by executing:

gem install opener-constituent-parser

Please keep in mind that all components in OpeNER take KAF as an input and output KAF by default.

Command line interface

You should now be able to call the constituent parser as a regular shell command: by its name. Once installed the gem normaly sits in your path so you can call it directly from anywhere.

This aplication reads a text from standard input in order to identify the language.

cat some_kind_of_kaf_file.kaf | constituent-parser

This is an excerpt of an example output:

<t id="ter761">
    <target id="t761" />
<t id="ter762">
    <target id="t762" />
<t id="ter763">
    <target id="t763" />
<!--Tree edges-->
<edge id="tre2051" from="nter1328" to="nter1327" />
<edge id="tre2052" from="nter1329" to="nter1328" />
<edge id="tre2053" from="nter1330" to="nter1329" />
<edge id="tre2054" from="nter1331" to="nter1330" head="yes" />
<edge id="tre2055" from="nter1332" to="nter1331" head="yes" />
<edge id="tre2056" from="nter1333" to="nter1332" />


You can launch a language identification webservice by executing:


This will launch a mini webserver with the webservice. It defaults to port 9292, so you can access it at http://localhost:9292.

To launch it on a different port provide the -p [port-number] option like this:

constituent-parser-server -p 1234

It then launches at http://localhost:1234

Documentation on the Webservice is provided by surfing to the urls provided above. For more information on how to launch a webservice run the command with the --help option.


Last but not least the constituent parser comes shipped with a daemon that can read jobs (and write) jobs to and from Amazon SQS queues. For more information type:

constituent-parser-daemon -h

Description of dependencies

This component runs best if you run it in an environment suited for OpeNER components. You can find an installation guide and helper tools in the OpeNER installer and an installation guide on the Opener Website

At least you need the following system setup:

Depenencies for normal use:

  • Jruby (1.7.9 or newer)
  • Java 1.7 or newer (There are problems with encoding in older versions).
  • Python 2.6

If you want to use the Dutch constituent parser you need to have:

Language Extension


Where to go from here

Report problem/Get help

If you encounter problems, please email [email protected] or leave an issue in the issue tracker.


  1. Fork it
  2. Create your feature branch (git checkout -b my-new-feature)
  3. Commit your changes (git commit -am 'Add some feature')
  4. Push to the branch (git push origin my-new-feature)
  5. Create new Pull Request