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Revision as of 11:19, 3 December 2014 by Wei2912 (talk | contribs) (→‎Conversion of PDF dictionary to lttoolbox format: Add final version of document if all goes well)
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My name is Wei En and I'm currently a GCI student. My blog is at

I decided to help out at Apertium because I find the work here quite interesting and I believe Apertium will benefit many.

The following are projects related to Apertium.

Wiktionary Crawler is a crawler for Wiktionary which aims to extract data from pages. It was created for a GCI task which you can read about at Task ideas for Google Code-in/Scrape inflection information from Wiktionary.

The crawler crawls a starting category (usually Category:XXX language)for subcategories, then crawls these subcategories for pages. It then passes the page to language-specific parsers which turn it into the Speling format.

The current languages supported are Chinese (zh), Thai (th) and Lao (lo). You are welcome to contribute to this project.

Spaceless Segmentation

Spaceless Segmentation has been merged into Apertium under It serves to tokenize languages without any whitespace. More information can be found under Task ideas for Google Code-in/Tokenisation for spaceless orthographies.

The tokeniser looks for possible tokenisations in the corpus text and selects the tokenisation which tokens appears the most in corpus.

A report comparing the above method, LRLM and RLLM (longest left to right matching and longest right to left matching respectively) is available at

Conversion of PDF dictionary to lttoolbox format

NOTE: This document is a draft.

In this example we're converting the following PDF file:

We copy the text directly from the PDF file, as PDF to text converters are currently unable to convert the text properly (thanks to the arcane PDF format).

Then, we pipe the text to our script:

# -*- coding: utf-8 -*-

import fileinput
import itertools
import re
import xml.etree.cElementTree as ET

BRACKETS_RE = re.compile(r'(\(.+?\)|\[.+?\])')
PAGENUMBER_RE = re.compile(r'^\d+$')
SPLIT_RE = re.compile(r'[;,]\s+')

    'a.': ['adj'],
    'adv.': ['adv'],
    'arch.': [],
    # cf. see also -- has been wiped out
    'comp.': [],
    # conv. converb, modifying verb -- covered later
    'dial.': [],
    'det.': ['det'],
    'Evk.': [],
    'exc.': ['ij'],
    'int.': ['itg'],
    'Mongo.': [],
    'n.': ['n'],
    'num.': ['det', 'qnt'],
    'ono.': [],
    'pl.': ['pl'],
    'pp.': ['post'],
    'pro.': ['prn'],
    'Russ.': [],
    'v.': ['v', 'TD']

class Entry(object):
    def __split(self, line):
        return SPLIT_RE.split(line)

    def __init__(self, line):
        tags = line.split()

        self.words = []
        self.abbrvs = []
        self.meanings = []

        found_abbrv = False
        found_conv = False
        for tag in tags:
            if tag in ABBRVS.keys(): # abbreviations
                found_abbrv = True
            elif tag == "conv.":
                found_abbrv = True
                found_conv = True

            if not found_abbrv: # entrys
            else: # translated

        # if there's "cf" in a word, we trim off everything else
        for i, word in enumerate(self.words):
            if word == "cf":
                self.words = self.words[:i]

        # if there's a converb, just look at the last word
        if found_conv:
            self.words = self.words[-1]
            self.words = " ".join(self.words)
        self.meanings = " ".join(self.meanings)

        self.words = strip_brackets(self.words)
        self.meanings = strip_brackets(self.meanings)

        if not self.abbrvs:
            self.words = None
            self.abbrvs = None
            self.meanings = None

        # preprocessing meanings
        self.meanings = self.meanings.replace("to", "")

        # split up meanings and entrys
        self.words = [x.strip() for x in self.__split(self.words)]
        self.meanings = [x.strip() for x in self.__split(self.meanings)]

def insert_blanks(element, line):
    words = line.split()
    if not words:
    element.text = words[0]
    element.tail = None
    blank = None
    for i in words[1:]:
        blank = ET.SubElement(element, 'b')
        blank.tail = i

def is_page_num(line):
    return PAGENUMBER_RE.match(line)

def strip_brackets(line):
    brackets =
    if brackets:
        for bracket in brackets.groups():
            line = line.replace(bracket, "")
    return line

def is_cyrillic(word):
    num_non_cyrillic = 0
    num_cyrillic = 0
    for c in word:
        ordc = ord(c)
        if 0x0400 <= ordc <= 0x04FF:
            num_cyrillic += 1
            num_non_cyrillic += 1
    return num_cyrillic > num_non_cyrillic

def preprocess(lines):
    def preprocess_line(line):
        if not line:
            return None
        line = line.strip()
        line = line.replace("•", "")
        line = line.replace("=", "")
        line = line.replace("cf.", "cf")
        line = strip_brackets(line)
        if not line or is_page_num(line):
            return None
        return line

    new_lines = []
    for i, line in enumerate(lines):
        line = preprocess_line(line)
        if not line:

        # check if next line should be merged with this line
        if i+1 < len(lines):
            words = line.split()
            next_line = preprocess_line(lines[i+1])
            if next_line:
                if (len(words) == 1 or
                    not is_cyrillic(next_line.split()[0])):
                    lines[i+1] = line + " " + next_line

        orig_word = ""
        for j, word in enumerate(words):
            if j+1 >= len(words):
            next_word = words[j+1]

            if word.endswith("."):
                orig_word = " ".join(words[:j])
            if word.endswith(";"):
                # if semicolon seperates dictionary entries
                if is_cyrillic(next_word):
                    words[j] = word.replace(";", "")
                    line = " ".join(words[:j+1])
                    next_line = " ".join(words[j+1:])
                    lines.insert(i+1, next_line)
                # if semicolon seperates abbreviations
                elif next_word.endswith("."):
                    words[j] = word.replace(";", "")
                    line = " ".join(words[:j+1])
                    next_line = orig_word + " " + " ".join(words[j+1:])
                    lines.insert(i+1, next_line)

        line = line.strip()
        if line:
    return new_lines

def main():
    dictionary = ET.Element("dictionary")
    pardefs = ET.SubElement(dictionary, "pardefs")

    lines = list(fileinput.input())
    new_lines = preprocess(lines)

    for line in new_lines:
        comment = ET.Comment(text=line)

        entry = Entry(line)
        if not (entry.words and entry.abbrvs and entry.meanings):

        for word, meaning in itertools.product(entry.words, entry.meanings):
            e = ET.SubElement(pardefs, "e")
            e.set('r', 'LR')

            p = ET.SubElement(e, 'p')

            # add word and meaning
            left = ET.SubElement(p, 'l')
            insert_blanks(left, word)

            right = ET.SubElement(p, 'r')
            insert_blanks(right, meaning)

            # add abbreviations
            for abbrv in entry.abbrvs:
                s = ET.Element('s')
                s.set('n', abbrv)


This will give us a XML dump of the dictionary, converted to the lttoolbox format. We format the XML file as shown here:

$ xmllint --format --encode utf8 file.xml > file.dix

The `--encode utf8` option prevents `xmllint` from escaping our unicode.

The final file format looks like this:

<?xml version="1.0" encoding="utf-8"?>
    <!--аа exc. Oh! See!-->
    <e r="LR">
        <l>аа<s n="ij"/></l>
        <r>Oh!<b/>See!<s n="ij"/></r>
    <!--ааҕыс v. to reckon with-->
    <e r="LR">
        <l>ааҕыс<s n="v"/><s n="TD"/></l>
        <r>reckon<b/>with<s n="v"/><s n="TD"/></r>
    <!--аайы a. each, every-->
    <e r="LR">
        <l>аайы<s n="adj"/></l>
        <r>each<s n="adj"/></r>
    <e r="LR">
        <l>аайы<s n="adj"/></l>
        <r>every<s n="adj"/></r>
    <!--күн аайы every day-->
    <!--аак cf аах n. document, paper-->
    <e r="LR">
        <l>аак<s n="n"/></l>
        <r>document<s n="n"/></r>
    <e r="LR">
        <l>аак<s n="n"/></l>
        <r>paper<s n="n"/></r>