Package: python-zpar
Introductionpython-zparis a python wrapper around theZPar
parser.
ZPar was written byYue Zhangwhile he was at Oxford University. According to its home page:ZPar is
a statistical natural language parser, which performs syntactic analysis
tasks including word segmentation, part-of-speech tagging and parsing.
ZPar supports multiple languages and multiple grammar formalisms. ZPar
has been most heavily developed for Chinese and English, while it
provides generic support for other languages. ZPar is fast, processing
above 50 sentences per second using the standard Penn Teebank (Wall
Street Journal) data.I wrote python-zpar since I needed a fast and efficient parser for my
NLP work which is primarily done in Python and not C++. I wanted to be
able to use this parser directly from Python without having to create a
bunch of files and running them through subprocesses. python-zpar not
only provides a simply python wrapper but also provides an XML-RPC ZPar
server to make batch-processing of large files easier.python-zpar usesctypes, a very
cool foreign function library bundled with Python that allows calling
functions in C DLLs or shared libraries directly.InstallationCurrently, python-zpar only works on 64-bit linux and OS X systems.
Those are the two platforms I use everyday. I am happy to try to get
python-zpar working on other platforms over time. Pull requests are
welcome!In order for python-zpar to work, it requires C functions that can be
called directly. Since the only user-exposed entry point in ZPar is the
command line client, I needed to write a shared library that would have
functions built on top of the ZPar functionality but expose them in a
way that ctypes could understand.Therefore, in order to build python-zpar from scratch, we need to
download the ZPar source, patch it with new functionality and compile
the shared library. All of this happens automatically when you install
with pip:pipinstallpython-zparIMPORTANT: On OS X, the installation will only work withgccinstalled using eithermacportsorhomebrew. The zpar source cannot be compiled withclang. If you are having trouble compiling the code after cloning
the repository or installing the package using pip, you can try
to explicitly override the C++ compiler:CXX=<pathtoc++compiler>make-eorCXX=<pathtoc++compiler>pipinstallpython-zparIf you are curious about what the C functions in the shared library
module look like, seesrc/zpar.lib.cpp.UsageTo use python-zpar, you need the English models for ZPar. They can be
downloaded from the ZPar release pagehere.
There are three models: a part-of-speech tagger, a constituency parser, and a
dependency parser. For the purpose of the examples below, the models are
in theenglish-modelsdirectory in the current directory.Here’s a small example of how to use python-zpar:fromsiximportprint_fromzparimportZPar# use the zpar wrapper as a context managerwithZPar('english-models')asz:# get the parser and the dependency parser modelstagger=z.get_tagger()depparser=z.get_depparser()# tag a sentencetagged_sent=tagger.tag_sentence("I am going to the market.")print_(tagged_sent)# tag an already tokenized sentencetagged_sent=tagger.tag_sentence("Do n't you want to come with me to the market ?",tokenize=False)print_(tagged_sent)# get the dependency parse of an already tagged sentencedep_parsed_sent=depparser.dep_parse_tagged_sentence("I/PRP am/VBP going/VBG to/TO the/DT market/NN ./.")print_(dep_parsed_sent)# get the dependency parse of an already tokenized sentencedep_parsed_sent=depparser.dep_parse_sentence("Do n't you want to come with me to the market ?",tokenize=False)print_(dep_parsed_sent)The above code sample produces the following output:I/PRP am/VBP going/VBG to/TO the/DT market/NN ./.

Do/VBP n't/RB you/PRP want/VBP to/TO come/VB with/IN me/PRP to/TO the/DT market/NN ?/.

I       PRP   1    SUB
am      VBP   -1   ROOT
going   VBG   1    VC
to      TO    2    VMOD
the     DT    5    NMOD
market  NN    3    PMOD
.       .     1    P

Do      VBP  -1  ROOT
n't     RB   0   VMOD
you     PRP  0   SUB
want    VBP  0   VMOD
to      TO   5   VMOD
come    VB   3   VMOD
with    IN   5   VMOD
me      PRP  6   PMOD
to      TO   5   VMOD
the     DT   10  NMOD
market  NN   8   PMOD
?       .    0   PDetailed usage with comments is shown in the included fileexamples/zpar_example.py. Runpython zpar_example.py-hto see a
list of all available options.ZPar ServerThe package also provides an python XML-RPC implementation of a ZPar
server that makes it easier to process multiple sentences and files by
loading the models just once (via the ctypes interface) and allowing
clients to connect and request analyses. The implementation is in the
executablezpar_serverthat is installed when you install the
package. The server is quite flexible and allows loading only the
models that you need. Here’s an example of how to start the server
with only the tagger and the dependency parser models loaded:$> zpar_server --modeldir english-models --models tagger parser depparser
INFO:Initializing server ...
Loading tagger from english-models/tagger
Loading model... done.
Loading constituency parser from english-models/conparser
Loading scores... done. (65.9334s)
Loading dependency parser from english-models/depparser
Loading scores... done. (14.9623s)
INFO:Registering introspection ...
INFO:Starting server on port 8859...Runzpar_server-hto see a list of all options.Once the server is running, you can connect to it using a client. An
example client is included in the fileexamples/zpar_client.pywhich
can be run as follows (note that if you specified a custom host and port
when running the server, you’d need to specify the same here):$> cd examples
$> python zpar_client.py

INFO:Attempting connection to http://localhost:8859
INFO:Tagging "Don't you want to come with me to the market?"
INFO:Output: Do/VBP n't/RB you/PRP want/VBP to/TO come/VB with/IN me/PRP to/TO the/DT market/NN ?/.
INFO:Tagging "Do n't you want to come to the market with me ?"
INFO:Output: Do/VBP n't/RB you/PRP want/VBP to/TO come/VB to/TO the/DT market/NN with/IN me/PRP ?/.
INFO:Parsing "Don't you want to come with me to the market?"
INFO:Output: (SQ (VBP Do) (RB n't) (NP (PRP you)) (VP (VBP want) (S (VP (TO to) (VP (VB come) (PP (IN with) (NP (PRP me))) (PP (TO to) (NP (DT the) (NN market))))))) (. ?))
INFO:Dep Parsing "Do n't you want to come to the market with me ?"
INFO:Output: Do VBP -1  ROOT
n't RB  0   VMOD
you PRP 0   SUB
want    VBP 0   VMOD
to  TO  5   VMOD
come    VB  3   VMOD
to  TO  5   VMOD
the DT  8   NMOD
market  NN  6   PMOD
with    IN  5   VMOD
me  PRP 9   PMOD
?   .   0   P

INFO:Tagging file /Users/nmadnani/work/python-zpar/examples/test.txt into test.tag
INFO:Parsing file /Users/nmadnani/work/python-zpar/examples/test_tokenized.txt into test.parseNote that python-zpar and all of the example scripts should work with
both Python 2.7 and Python 3.4. I have tested python-zpar on both Linux
and Mac but not on Windows.Node.js versionIf you want to use ZPar in your node.js app, check out my other projectnode-zpar.LicenseAlthough python-zpar is licensed under the MIT license - which means
that you can do whatever you want with the wrapper code - ZPar itself is
licensed under GPL v3.ToDoImprove error handling on both the python and C side.Expose more functionality, e.g., Chinese word segmentation, parsing
etc.May be look into usingCFFIinstead of ctypes.