tokenizer

Tokenizer: A tokenizer for Icelandic text

Overview

Tokenization is a necessary first step in many natural language processing tasks, such as word counting, parsing, spell checking, corpus generation, and statistical analysis of text.

Tokenizer is a compact pure-Python (>=3.9) executable program and module for tokenizing Icelandic text. It converts input text to streams of tokens, where each token is a separate word, punctuation sign, number/amount, date, e-mail, URL/URI, etc. It also segments the token stream into sentences, considering corner cases such as abbreviations and dates in the middle of sentences.

The package contains a dictionary of common Icelandic abbreviations, in the file src/tokenizer/Abbrev.conf.

Tokenizer is an independent spinoff from the Greynir project (GitHub repository here), by the same authors. The Greynir natural language parser for Icelandic uses Tokenizer on its input.

Tokenizer is licensed under the MIT license.

Indicative performance

Time to tokenize 1 MB of a wide selection of texts from the Icelandic Gigaword Corpus using a 64-bit 2.6 GHz Intel Core i9:

	Time (sec)
CPython 3.12	25.27
PyPy 3.11	8.08

Running tokenization with PyPy is about 3x faster than with CPython.

Deep vs. shallow tokenization

Tokenizer can do both deep and shallow tokenization.

Shallow tokenization simply returns each sentence as a string (or as a line of text in an output file), where the individual tokens are separated by spaces.

Deep tokenization returns token objects that have been annotated with the token type and further information extracted from the token, for example a (year, month, day) tuple in the case of date tokens.

In shallow tokenization, tokens are in most cases kept intact, although consecutive white space is always coalesced. The input strings "800 MW", "21. janúar" and "800 7000" thus become two tokens each, output with a single space between them.

In deep tokenization, the same strings are represented by single token objects, of type TOK.MEASUREMENT, TOK.DATEREL and TOK.TELNO, respectively. The text associated with a single token object may contain spaces, although consecutive whitespace is always coalesced into a single space " ".

By default, the command line tool performs shallow tokenization. If you want deep tokenization with the command line tool, use the --json or --csv switches.

From Python code, call split_into_sentences() for shallow tokenization, or tokenize() for deep tokenization. These functions are documented with examples below.

Installation

To install:

$ pip install tokenizer

Command line tool

After installation, the tokenizer can be invoked directly from the command line:

$ tokenize input.txt output.txt

Input and output files are assumed to be UTF-8 encoded. If the file names are not given explicitly, stdin and stdout are used for input and output, respectively.

Empty lines in the input are treated as hard sentence boundaries.

By default, the output consists of one sentence per line, where each line ends with a single newline character (ASCII LF, chr(10), \n). Within each line, tokens are separated by spaces.

The following (mutually exclusive) options can be specified on the command line:

Option	Description
--csv	Deep tokenization. Output token objects in CSV format, one per line. Each line contains: token kind (number), normalized text, value (if applicable), original text with preserved whitespace, and character span indices. Sentences are separated by lines containing 0,"","","","".
--json	Deep tokenization. Output token objects in JSON format, one per line. Each JSON object contains: k (token kind), t (normalized text), v (value if applicable), o (original text with preserved whitespace), s (character span indices).

Other options can be specified on the command line:

Option	Description
-n, --normalize	Normalize punctuation: quotes output in Icelandic form („these“), ellipsis as single character (…), year ranges with en-dash (1914–1918), and em-dashes centered with spaces ( — ). This option is only applicable to shallow tokenization.
-s, --one_sent_per_line	Input contains strictly one sentence per line, i.e. every newline is a sentence boundary.
-o, --original	Output original token text, i.e. bypass shallow tokenization. This effectively runs the tokenizer as a sentence splitter only.
-m, --convert_measurements	Degree signal in tokens denoting temperature normalized (200° C -> 200 °C).
-p, --coalesce_percent	Numbers combined into one token with the following token denoting percentage word forms (prósent, prósentustig, hundraðshlutar).
-g, --keep_composite_glyphs	Do not replace composite glyphs using Unicode COMBINING codes with their accented/umlaut counterparts.
-e, --replace_html_escapes	HTML escape codes replaced by their meaning, such as á -> á.
-c, --convert_numbers	English-style decimal points and thousands separators in numbers changed to Icelandic style.

Type tokenize -h or tokenize --help to get a short help message.

Example

$ echo "3.janúar sl. keypti   ég 64kWst rafbíl. Hann kostaði € 30.000." | tokenize
3. janúar sl. keypti ég 64kWst rafbíl .
Hann kostaði €30.000 .

$ echo "3.janúar sl. keypti   ég 64kWst rafbíl. Hann kostaði € 30.000." | tokenize --csv
19,"3. janúar","0|1|3","3.janúar","0-1-2-2-3-4-5-6-7"
6,"sl.","síðastliðinn"," sl.","1-2-3"
6,"keypti",""," keypti","1-2-3-4-5-6"
6,"ég","","   ég","3-4"
22,"64kWst","J|230400000.0"," 64kWst","1-2-3-4-5-6"
6,"rafbíl",""," rafbíl","1-2-3-4-5-6"
1,".",".",".","0"
0,"","","",""
6,"Hann",""," Hann","1-2-3-4"
6,"kostaði",""," kostaði","1-2-3-4-5-6-7"
13,"€30.000","30000|EUR"," € 30.000","1-3-4-5-6-7-8"
1,".",".",".","0"
0,"","","",""

$ echo "3.janúar sl. keypti   ég 64kWst rafbíl. Hann kostaði € 30.000." | tokenize --json
{"k":"BEGIN SENT"}
{"k":"DATEREL","t":"3. janúar","v":[0,1,3],"o":"3.janúar","s":[0,1,2,2,3,4,5,6,7]}
{"k":"WORD","t":"sl.","v":["síðastliðinn"],"o":" sl.","s":[1,2,3]}
{"k":"WORD","t":"keypti","o":" keypti","s":[1,2,3,4,5,6]}
{"k":"WORD","t":"ég","o":"   ég","s":[3,4]}
{"k":"MEASUREMENT","t":"64kWst","v":["J",230400000.0],"o":" 64kWst","s":[1,2,3,4,5,6]}
{"k":"WORD","t":"rafbíl","o":" rafbíl","s":[1,2,3,4,5,6]}
{"k":"PUNCTUATION","t":".","v":".","o":".","s":[0]}
{"k":"END SENT"}
{"k":"BEGIN SENT"}
{"k":"WORD","t":"Hann","o":" Hann","s":[1,2,3,4]}
{"k":"WORD","t":"kostaði","o":" kostaði","s":[1,2,3,4,5,6,7]}
{"k":"AMOUNT","t":"€30.000","v":[30000,"EUR"],"o":" € 30.000","s":[1,3,4,5,6,7,8]}
{"k":"PUNCTUATION","t":".","v":".","o":".","s":[0]}
{"k":"END SENT"}

CSV Output Format

When using --csv, each token is output as a CSV row with the following five fields:

• Token kind (number): Numeric code representing the token type (e.g., 6 for WORD, 19 for DATEREL, 1 for PUNCTUATION)
• Normalized text: The processed text of the token
• Value: The parsed value, if applicable (e.g., date tuples, amounts, abbreviation expansions), or empty string
• Original text: The original text including preserved whitespace
• Span indices: Character indices mapping each character in the normalized text to its position in the original text, separated by hyphens

Sentences are separated by rows containing 0,"","","","".

JSON Output Format

When using --json, each token is output as a JSON object on a separate line with the following fields:

• k (kind): The token type description (e.g., "WORD", "DATEREL", "PUNCTUATION")
• t (text): The normalized/processed text of the token
• v (value): The parsed value, if applicable (e.g., date tuples, amounts, abbreviation expansions)
• o (original): The original text including preserved whitespace
• s (span): Character indices mapping each character in the normalized text to its position in the original text

Python module

Shallow tokenization example

An example of shallow tokenization from Python code goes something like this:

from tokenizer import split_into_sentences

# A string to be tokenized, containing two sentences
s = "3.janúar sl. keypti   ég 64kWst rafbíl. Hann kostaði € 30.000."

# Obtain a generator of sentence strings
g = split_into_sentences(s)

# Loop through the sentences
for sentence in g:

    # Obtain the individual token strings
    tokens = sentence.split()

    # Print the tokens, comma-separated
    print("|".join(tokens))

The program outputs:

3.|janúar|sl.|keypti|ég|64kWst|rafbíl|.
Hann|kostaði|€30.000|.

Deep tokenization example

To do deep tokenization from within Python code:

from tokenizer import tokenize, TOK

text = ("Málinu var vísað til stjórnskipunar- og eftirlitsnefndar "
    "skv. 3. gr. XVII. kafla laga nr. 10/2007 þann 3. janúar 2010.")

for token in tokenize(text):

    print("{0}: '{1}' {2}".format(
        TOK.descr[token.kind],
        token.txt or "-",
        token.val or ""))

Output:

BEGIN SENT: '-' (0, None)
WORD: 'Málinu'
WORD: 'var'
WORD: 'vísað'
WORD: 'til'
WORD: 'stjórnskipunar- og eftirlitsnefndar'
WORD: 'skv.' [('samkvæmt', 0, 'fs', 'skst', 'skv.', '-')]
ORDINAL: '3.' 3
WORD: 'gr.' [('grein', 0, 'kvk', 'skst', 'gr.', '-')]
ORDINAL: 'XVII.' 17
WORD: 'kafla'
WORD: 'laga'
WORD: 'nr.' [('númer', 0, 'hk', 'skst', 'nr.', '-')]
NUMBER: '10' (10, None, None)
PUNCTUATION: '/' (4, '/')
YEAR: '2007' 2007
WORD: 'þann'
DATEABS: '3. janúar 2010' (2010, 1, 3)
PUNCTUATION: '.' (3, '.')
END SENT: '-'

Note the following:

• Sentences are delimited by TOK.S_BEGIN and TOK.S_END tokens.
• Composite words, such as stjórnskipunar- og eftirlitsnefndar, are coalesced into one token.
• Well-known abbreviations are recognized and their full expansion is available in the token.val field.
• Ordinal numbers (3., XVII.) are recognized and their value (3, 17) is available in the token.val field.
• Dates, years and times, both absolute and relative, are recognized and the respective year, month, day, hour, minute and second values are included as a tuple in token.val.
• Numbers, both integer and real, are recognized and their value is available in the token.val field.
• Further details of how Tokenizer processes text can be inferred from the test module in the project's GitHub repository.

The tokenize() function

To deep-tokenize a text string, call tokenizer.tokenize(text, **options). The text parameter can be a string, or an iterable that yields strings (such as a text file object).

The function returns a Python generator of token objects. Each token object is a simple namedtuple with three fields: (kind, txt, val) (further documented below).

The tokenizer.tokenize() function is typically called in a for loop:

import tokenizer
for token in tokenizer.tokenize(mystring):
    kind, txt, val = token
    if kind == tokenizer.TOK.WORD:
        # Do something with word tokens
        pass
    else:
        # Do something else
        pass

Alternatively, create a token list from the returned generator:

token_list = list(tokenizer.tokenize(mystring))

The split_into_sentences() function

To shallow-tokenize a text string, call tokenizer.split_into_sentences(text_or_gen, **options). The text_or_gen parameter can be a string, or an iterable that yields strings (such as a text file object).

This function returns a Python generator of strings, yielding a string for each sentence in the input. Within a sentence, the tokens are separated by spaces.

You can pass the option normalize=True to the function if you want the normalized form of punctuation tokens. Normalization outputs Icelandic single and double quotes („these“) instead of English-style ones ("these"), converts three-dot ellipsis ... to single character ellipsis …, normalizes year ranges to use en-dash (1914–1918), and ensures em-dashes are centered with spaces ( — ).

The tokenizer.split_into_sentences() function is typically called in a for loop:

import tokenizer
with open("example.txt", "r", encoding="utf-8") as f:
    # You can pass a file object directly to split_into_sentences()
    for sentence in tokenizer.split_into_sentences(f):
        # sentence is a string of space-separated tokens
        tokens = sentence.split()
        # Now, tokens is a list of strings, one for each token
        for t in tokens:
            # Do something with the token t
            pass

The correct_spaces() function

The tokenizer.correct_spaces(text) function returns a string after splitting it up and re-joining it with correct whitespace around punctuation tokens. Example:

>>> import tokenizer
>>> tokenizer.correct_spaces(
... "Frétt \n  dagsins:Jón\t ,Friðgeir og Páll ! 100  /  2  =   50"
... )
'Frétt dagsins: Jón, Friðgeir og Páll! 100/2 = 50'

The detokenize() function

The tokenizer.detokenize(tokens, normalize=False) function takes an iterable of token objects and returns a corresponding, correctly spaced text string, composed from the tokens' text. If the normalize parameter is set to True, the function uses the normalized form of any punctuation tokens, such as proper Icelandic single and double quotes instead of English-type quotes. Example:

>>> import tokenizer
>>> toklist = list(tokenizer.tokenize("Hann sagði: \"Þú ert ágæt!\"."))
>>> tokenizer.detokenize(toklist, normalize=True)
'Hann sagði: \u201eÞú ert ágæt!\u201c.'

The normalized_text() function

The tokenizer.normalized_text(token) function returns the normalized text for a token. This means that the original token text is returned except for certain punctuation tokens, where a normalized form is returned instead. Specifically, English-type quotes are converted to Icelandic ones („these“), hyphens in year ranges are converted to en-dash (1914–1918), and consecutive identical dashes are preserved as multi-character tokens.

The text_from_tokens() function

The tokenizer.text_from_tokens(tokens) function returns a concatenation of the text contents of the given token list, with spaces between tokens. Example:

>>> import tokenizer
>>> toklist = list(tokenizer.tokenize("Hann sagði: \"Þú ert ágæt!\"."))
>>> tokenizer.text_from_tokens(toklist)
'Hann sagði : " Þú ert ágæt ! " .'

The normalized_text_from_tokens() function

The tokenizer.normalized_text_from_tokens(tokens) function returns a concatenation of the normalized text contents of the given token list, with spaces between tokens. Example (note the double quotes):

>>> import tokenizer
>>> toklist = list(tokenizer.tokenize("Hann sagði: \"Þú ert ágæt!\"."))
>>> tokenizer.normalized_text_from_tokens(toklist)
'Hann sagði : „ Þú ert ágæt ! “ .'

Tokenization options

You can optionally pass one or more of the following options as keyword parameters to the tokenize() and split_into_sentences() functions:

• convert_numbers=[bool]

  Setting this option to True causes the tokenizer to convert numbers and amounts with English-style decimal points (.) and thousands separators (,) to Icelandic format, where the decimal separator is a comma (,) and the thousands separator is a period (.). $1,234.56 is thus converted to a token whose text is $1.234,56.

  The default value for the convert_numbers option is False.

  Note that in versions of Tokenizer prior to 1.4, convert_numbers was True.

• convert_measurements=[bool]

  Setting this option to True causes the tokenizer to convert degrees Kelvin, Celsius and Fahrenheit to a regularized form, i.e. 200° C becomes 200 °C.

  The default value for the convert_measurements option is False.

• replace_composite_glyphs=[bool]

  Setting this option to False disables the automatic replacement of composite Unicode glyphs with their corresponding Icelandic characters. By default, the tokenizer combines vowels with the Unicode COMBINING ACUTE ACCENT and COMBINING DIAERESIS glyphs to form single character code points, such as 'á' and 'ö'.

  The default value for the replace_composite_glyphs option is True.

• replace_html_escapes=[bool]

  Setting this option to True causes the tokenizer to replace common HTML escaped character codes, such as á with the character being escaped, such as á. Note that ­ (soft hyphen) is replaced by an empty string, and   is replaced by a normal space. The ligatures fi and fl are replaced by fi and fl, respectively.

  The default value for the replace_html_escapes option is False.

Dash and Hyphen Handling

Tokenizer distinguishes between three dash types and handles them contextually:

• Hyphen (-): Regular hyphen, used e.g. in compound words
• En-dash (–): Longer dash, preferred in Icelandic for year/date ranges
• Em-dash (—): Longest dash, used for emphasis or parenthetical remarks

Context-Specific Behavior

Year ranges: Hyphens between years are normalized to en-dash when normalize=True, following Icelandic spelling rules: 1914-1918 → 1914–1918.

Free-standing dashes: Hyphens and en-dashes with spaces around them preserve those spaces: word - word remains word - word, not word-word.

Composite word continuations: Hyphens stay attached to preceding words in patterns like fjölskyldu- og húsdýragarðurinn, and to succeeding words in cases like eldhúsborð og -stólar.

Em-dashes: Treated as centered punctuation with spaces on both sides: word—word → word — word.

Consecutive dashes: Multiple identical dashes (--, ––, ——) are treated as single tokens and preserve their spacing.

Edge Cases

The tokenizer correctly handles 1914 -1918 where -1918 might appear to be a negative number but is actually part of a year range.

The token object

Each token is an instance of the class Tok that has three main properties: kind, txt and val.

The kind property

The kind property contains one of the following integer constants, defines within the TOK class:

Constant	Value	Explanation	Examples
PUNCTUATION	1	Punctuation	. ! ; % &
TIME	2	Time (h, m, s)	11:35:40, kl. 7:05, klukkan 23:35
DATE *	3	Date (y, m, d)	[Unused, see DATEABS and DATEREL]
YEAR	4	Year	árið 874 e.Kr., 1965, 44 f.Kr.
NUMBER	5	Number	100, 1.965, 1.965,34, 1,965.34, 2⅞
WORD	6	Word	kattaeftirlit, hunda- og kattaeftirlit
TELNO	7	Telephone number	5254764, 699-4244, 410 4000
PERCENT	8	Percentage	78%
URL	9	URL	https://greynir.is, http://tiny.cc/28695y
ORDINAL	10	Ordinal number	30., XVIII.
TIMESTAMP *	11	Timestamp	[Unused, see TIMESTAMPABS and TIMESTAMPREL]
CURRENCY *	12	Currency name	[Unused]
AMOUNT	13	Amount	€2.345,67, 750 þús.kr., 2,7 mrð. USD, kr. 9.900, EUR 200
PERSON *	14	Person name	[Unused]
EMAIL	15	E-mail	[e-mail]
ENTITY *	16	Named entity	[Unused]
UNKNOWN	17	Unknown token
DATEABS	18	Absolute date	30. desember 1965, 30/12/1965, 1965-12-30, 1965/12/30
DATEREL	19	Relative date	15. mars, 15/3, 15.3., mars 1911
TIMESTAMPABS	20	Absolute timestamp	30. desember 1965 11:34, 1965-12-30 kl. 13:00
TIMESTAMPREL	21	Relative timestamp	30. desember kl. 13:00
MEASUREMENT	22	Value with a measurement unit	690 MW, 1.010 hPa, 220 m², 80° C
NUMWLETTER	23	Number followed by a single letter	14a, 7B
DOMAIN	24	Domain name	greynir.is, Reddit.com, www.wikipedia.org
HASHTAG	25	Hashtag	#MeToo, #12stig
MOLECULE	26	Molecular formula	H2SO4, CO2
SSN	27	Social security number (kennitala)	591213-1480
USERNAME	28	Twitter user handle	@username_123
SERIALNUMBER	29	Serial number	394-5388, 12-345-6789
COMPANY *	30	Company name	[Unused]
S_BEGIN	11001	Start of sentence
S_END	11002	End of sentence

(*) The token types marked with an asterisk are reserved for the GreynirEngine package and not currently returned by the tokenizer.

To obtain a descriptive text for a token kind, use TOK.descr[token.kind] (see example above).

The txt property

The txt property contains the original source text for the token, with the following exceptions:

• All contiguous whitespace (spaces, tabs, newlines) is coalesced into single spaces (" ") within the txt string. A date token that is parsed from a source text of "29. \n janúar" thus has a txt of "29. janúar".

• Tokenizer automatically merges Unicode COMBINING ACUTE ACCENT (code point 769) and COMBINING DIAERESIS (code point 776) with vowels to form single code points for the Icelandic letters á, é, í, ó, ú, ý and ö, in both lower and upper case. (This behavior can be disabled; see the replace_composite_glyphs option described above.)

• If the convert_numbers option is specified (see above), English-style thousand and decimal separators are converted to Icelandic ones (10,345.67 becomes 10.345,67).

• If the replace_html_escapes option is set, Tokenizer replaces HTML-style escapes (á) with the characters being escaped (á).

The val property

The val property contains auxiliary information, corresponding to the token kind, as follows:

• For TOK.PUNCTUATION, the val field contains a tuple with two items: (whitespace, normalform). The first item (token.val[0]) specifies the whitespace normally found around the symbol in question, as an integer:

  TP_LEFT = 1 # Whitespace to the left TP_CENTER = 2 # Whitespace to the left and right TP_RIGHT = 3 # Whitespace to the right TP_NONE = 4 # No whitespace

The second item (token.val[1]) contains a normalized representation of the punctuation. For instance, various forms of single and double quotes are represented as Icelandic ones (i.e. „these“ or ‚these‘) in normalized form, and ellipsis ("...") are represented as the single character "…".

• For TOK.TIME, the val field contains an (hour, minute, second) tuple.

• For TOK.DATEABS, the val field contains a (year, month, day) tuple (all 1-based).

• For TOK.DATEREL, the val field contains a (year, month, day) tuple (all 1-based), except that a least one of the tuple fields is missing and set to 0. Example: 3. júní becomes TOK.DATEREL with the fields (0, 6, 3) as the year is missing.

• For TOK.YEAR, the val field contains the year as an integer. A negative number indicates that the year is BCE (fyrir Krist), specified with the suffix f.Kr. (e.g. árið 33 f.Kr.).

• For TOK.NUMBER, the val field contains a tuple (number, None, None). (The two empty fields are included for compatibility with Greynir.)

• For TOK.WORD, the val field contains the full expansion of an abbreviation, as a list containing a single tuple, or None if the word is not abbreviated.

• For TOK.PERCENT, the val field contains a tuple of (percentage, None, None).

• For TOK.ORDINAL, the val field contains the ordinal value as an integer. The original ordinal may be a decimal number or a Roman numeral.

• For TOK.TIMESTAMP, the val field contains a (year, month, day, hour, minute, second) tuple.

• For TOK.AMOUNT, the val field contains an (amount, currency, None, None) tuple. The amount is a float, and the currency is an ISO currency code, e.g. USD for dollars ($ sign), EUR for euros (€ sign) or ISK for Icelandic króna (kr. abbreviation). (The two empty fields are included for compatibility with Greynir.)

• For TOK.MEASUREMENT, the val field contains a (unit, value) tuple, where unit is a base SI unit (such as g, m, m², s, W, Hz, K for temperature in Kelvin).

• For TOK.TELNO, the val field contains a tuple: (number, cc) where the first item is the phone number in a normalized NNN-NNNN format, i.e. always including a hyphen, and the second item is the country code, eventually prefixed by +. The country code defaults to 354 (Iceland).

Abbreviations

Abbreviations recognized by Tokenizer are defined in the Abbrev.conf file, found in the src/tokenizer/ directory. This is a text file with abbreviations, their definitions and explanatory comments.

When an abbreviation is encountered, it is recognized as a word token (i.e. having its kind field equal to TOK.WORD). Its expansion(s) are included in the token's val field as a list containing tuples of the format (ordmynd, utg, ordfl, fl, stofn, beyging). An example is o.s.frv., which results in a val field equal to [('og svo framvegis', 0, 'ao', 'frasi', 'o.s.frv.', '-')].

The tuple format is designed to be compatible with the Database of Icelandic Morphology (DIM), Beygingarlýsing íslensks nútímamáls, i.e. the so-called Sigrúnarsnið.

Development installation

To install Tokenizer in development mode, where you can easily modify the source files (assuming you have git available):

$ git clone https://github.com/mideind/Tokenizer
$ cd Tokenizer
$ # [ Activate your virtualenv here, if you have one ]
$ pip install -e ".[dev]"

Test suite

Tokenizer comes with a large test suite. The file test/test_tokenizer.py contains built-in tests that run under pytest.

To run the built-in tests, install pytest, cd to your Tokenizer subdirectory (and optionally activate your virtualenv), then run:

$ python -m pytest

The file test/toktest_large.txt contains a test set of 13,075 lines. The lines test sentence detection, token detection and token classification. For analysis, test/toktest_large_gold_perfect.txt contains the expected output of a perfect shallow tokenization, and test/toktest_large_gold_acceptable.txt contains the current output of the shallow tokenization.

The file test/Overview.txt (only in Icelandic) contains a description of the test set, including line numbers for each part in both test/toktest_large.txt and test/toktest_large_gold_acceptable.txt, and a tag describing what is being tested in each part.

It also contains a description of a perfect shallow tokenization for each part, acceptable tokenization and the current behaviour. As such, the description is an analysis of which edge cases the tokenizer can handle and which it can not.

To test the tokenizer on the large test set the following needs to be typed in the command line:

$ tokenize test/toktest_large.txt test/toktest_large_out.txt

To compare it to the acceptable behaviour:

$ diff test/toktest_large_out.txt test/toktest_large_gold_acceptable.txt > diff.txt

The file test/toktest_normal.txt contains a running text from recent news articles, containing no edge cases. The gold standard for that file can be found in the file test/toktest_normal_gold_expected.txt.

Changelog

• Version 3.6.0: Removed the deprecated --handle_kludgy_ordinals CLI flag and handle_kludgy_ordinals API option. Kludgy ordinals (e.g. 1sti, 3ja) are now always passed through unchanged as word tokens.
• Version 3.5.5: Maintenance release with modernized package metadata (PEP 517/518 build system, enhanced PyPI discoverability with keywords and URLs), improved tooling configuration (ruff, mypy, pytest), and type checking improvements. CI updated for setuptools compatibility.
• Version 3.5.4: Improved dash and hyphen handling: free-standing hyphens between words now preserve spaces, year ranges normalize to en-dash (with normalize=True), em-dashes are centered with spaces, and consecutive identical dashes are handled as single tokens. Fixed edge case where negative years in ranges (e.g., "1914 -1918") were incorrectly parsed as negative numbers.
• Version 3.5.3: Fixed PyPI package description display (README.md reference in pyproject.toml)
• Version 3.5.2: Improved JSON output format and BIN_Tuple representation; documentation updates
• Version 3.5.1: Fixed bug in composite glyph handling
• Version 3.5.0: Better handling of colon-separated timestamps and URI schemes, modernization, and more.
• Version 3.4.5: Compatibility with Python 3.13. Now requires Python 3.9 or later.
• Version 3.4.4: Better handling of abbreviations
• Version 3.4.3: Various minor fixes. Now requires Python 3.8 or later.
• Version 3.4.2: Abbreviations and phrases added, META_BEGIN token added.
• Version 3.4.1: Improved performance on long input chunks.
• Version 3.4.0: Improved handling and normalization of punctuation.
• Version 3.3.2: Internal refactoring; bug fixes in paragraph handling.
• Version 3.3.1: Fixed bug where opening quotes at the start of paragraphs were sometimes incorrectly recognized and normalized.
• Version 3.2.0: Numbers and amounts that consist of word tokens only ('sex hundruð') are now returned as the original TOK.WORD s ('sex' and 'hundruð'), not as single coalesced TOK.NUMBER / TOK.AMOUNT /etc. tokens.
• Version 3.1.2: Changed paragraph markers to [[ and ]] (removing spaces).
• Version 3.1.1: Minor fixes; added Tok.from_token().
• Version 3.1.0: Added -o switch to the tokenize command to return original token text, enabling the tokenizer to run as a sentence splitter only.
• Version 3.0.0: Added tracking of character offsets for tokens within the original source text. Added full type annotations. Dropped Python 2.7 support.
• Version 2.5.0: Added arguments for all tokenizer options to the command-line tool. Type annotations enhanced.
• Version 2.4.0: Fixed bug where certain well-known word forms (fá, fær, mín, sá...) were being interpreted as (wrong) abbreviations. Also fixed bug where certain abbreviations were being recognized even in uppercase and at the end of a sentence, for instance Örn.
• Version 2.3.1: Various bug fixes; fixed type annotations for Python 2.7; the token kind NUMBER WITH LETTER is now NUMWLETTER.
• Version 2.3.0: Added the replace_html_escapes option to the tokenize() function.
• Version 2.2.0: Fixed correct_spaces() to handle compounds such as Atvinnu-, nýsköpunar- og ferðamálaráðuneytið and bensínstöðvar, -dælur og -tankar.
• Version 2.1.0: Changed handling of periods at end of sentences if they are a part of an abbreviation. Now, the period is kept attached to the abbreviation, not split off into a separate period token, as before.
• Version 2.0.7: Added TOK.COMPANY token type; fixed a few abbreviations; renamed parameter text to text_or_gen in functions that accept a string or a string iterator.
• Version 2.0.6: Fixed handling of abbreviations such as m.v. (miðað við) that should not start a new sentence even if the following word is capitalized.
• Version 2.0.5: Fixed bug where single uppercase letters were erroneously being recognized as abbreviations, causing prepositions such as 'Í' and 'Á' at the beginning of sentences to be misunderstood in GreynirEngine.
• Version 2.0.4: Added imperfect abbreviations (amk., osfrv.); recognized klukkan hálf tvö as a TOK.TIME.
• Version 2.0.3: Fixed bug in detokenize() where abbreviations, domains and e-mails containing periods were wrongly split.
• Version 2.0.2: Spelled-out day ordinals are no longer included as a part of TOK.DATEREL tokens. Thus, þriðji júní is now a TOK.WORD followed by a TOK.DATEREL. 3. júní continues to be parsed as a single TOK.DATEREL.
• Version 2.0.1: Order of abbreviation meanings within the token.val field made deterministic; fixed bug in measurement unit handling.
• Version 2.0.0: Added command line tool; added split_into_sentences() and detokenize() functions; removed convert_telno option; splitting of coalesced tokens made more robust; added TOK.SSN, TOK.MOLECULE, TOK.USERNAME and TOK.SERIALNUMBER token kinds; abbreviations can now have multiple meanings.
• Version 1.4.0: Added the **options parameter to the tokenize() function, giving control over the handling of numbers and telephone numbers.
• Version 1.3.0: Added TOK.DOMAIN and TOK.HASHTAG token types; improved handling of capitalized month name Ágúst, which is now recognized when following an ordinal number; improved recognition of telephone numbers; added abbreviations.
• Version 1.2.3: Added abbreviations; updated GitHub URLs.
• Version 1.2.2: Added support for composites with more than two parts, i.e. „dómsmála-, ferðamála-, iðnaðar- og nýsköpunarráðherra“; added support for ± sign; added several abbreviations.
• Version 1.2.1: Fixed bug where the name Ágúst was recognized as a month name; Unicode nonbreaking and invisible space characters are now removed before tokenization.
• Version 1.2.0: Added support for Unicode fraction characters; enhanced handing of degrees (°, °C, °F); fixed bug in cubic meter measurement unit; more abbreviations.
• Version 1.1.2: Fixed bug in liter (l and ltr) measurement units.
• Version 1.1.1: Added mark_paragraphs() function.
• Version 1.1.0: All abbreviations in Abbrev.conf are now returned with their meaning in a tuple in token.val; handling of 'mbl.is' fixed.
• Version 1.0.9: Added abbreviation 'MAST'; harmonized copyright headers.
• Version 1.0.8: Bug fixes in DATEREL, MEASUREMENT and NUMWLETTER token handling; added 'kWst' and 'MWst' measurement units; blackened.
• Version 1.0.7: Added TOK.NUMWLETTER token type.
• Version 1.0.6: Automatic merging of Unicode COMBINING ACUTE ACCENT and COMBINING DIAERESIS code points with vowels.
• Version 1.0.5: Date/time and amount tokens coalesced to a further extent.
• Version 1.0.4: Added TOK.DATEABS, TOK.TIMESTAMPABS, TOK.MEASUREMENT.

MIT License

Copyright (C) 2016-2025 Miðeind ehf. Original author: Vilhjálmur Þorsteinsson

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

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