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f85a485f89
We currently have several sets of files generated from data provided
by Unicode. These all have ad hoc rules and instructions for updating
when new Unicode versions appear, and it's not done consistently.
This patch centralizes and automates the process and makes it part of
the release checklist. The Unicode and CLDR versions are specified in
Makefile.global.in. There is a new make target "update-unicode" that
downloads all the relevant files and runs the generation script.
There is also a new script for generating the table of combining
characters for ucs_wcwidth(). That table is now in a separate include
file rather than hardcoded into the middle of other code. This is
based on the script that was used for generating
d8594d123c, but the script itself wasn't
committed at that time.
Reviewed-by: John Naylor <john.naylor@2ndquadrant.com>
Discussion: https://www.postgresql.org/message-id/flat/c8d05f42-443e-6c23-819b-05b31759a37c@2ndquadrant.com
292 lines
13 KiB
Python
292 lines
13 KiB
Python
#!/usr/bin/python
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# -*- coding: utf-8 -*-
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#
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# This script builds unaccent.rules on standard output when given the
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# contents of UnicodeData.txt [1] and Latin-ASCII.xml [2] given as
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# arguments. Optionally includes ligature expansion and Unicode CLDR
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# Latin-ASCII transliterator, enabled by default, this can be disabled
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# with "--no-ligatures-expansion" command line option.
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#
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# The approach is to use the Unicode decomposition data to identify
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# precomposed codepoints that are equivalent to a ligature of several
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# letters, or a base letter with any number of diacritical marks.
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#
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# This approach handles most letters with diacritical marks and some
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# ligatures. However, several characters (notably a majority of
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# ligatures) don't have decomposition. To handle all these cases, one can
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# use a standard Unicode transliterator available in Common Locale Data
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# Repository (CLDR): Latin-ASCII. This transliterator associates Unicode
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# characters to ASCII-range equivalent. Unless "--no-ligatures-expansion"
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# option is enabled, the XML file of this transliterator [2] -- given as a
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# command line argument -- will be parsed and used.
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#
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# Ideally you should use the latest release for each data set. This
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# script is compatible with at least CLDR release 29.
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#
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# [1] https://www.unicode.org/Public/${UNICODE_VERSION}/ucd/UnicodeData.txt
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# [2] https://raw.githubusercontent.com/unicode-org/cldr/${TAG}/common/transforms/Latin-ASCII.xml
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# BEGIN: Python 2/3 compatibility - remove when Python 2 compatibility dropped
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# The approach is to be Python3 compatible with Python2 "backports".
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from __future__ import print_function
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from __future__ import unicode_literals
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# END: Python 2/3 compatibility - remove when Python 2 compatibility dropped
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import argparse
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import codecs
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import re
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import sys
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import xml.etree.ElementTree as ET
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# BEGIN: Python 2/3 compatibility - remove when Python 2 compatibility dropped
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if sys.version_info[0] <= 2:
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# Encode stdout as UTF-8, so we can just print to it
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sys.stdout = codecs.getwriter('utf8')(sys.stdout)
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# Map Python 2's chr to unichr
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chr = unichr
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# Python 2 and 3 compatible bytes call
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def bytes(source, encoding='ascii', errors='strict'):
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return source.encode(encoding=encoding, errors=errors)
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else:
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# END: Python 2/3 compatibility - remove when Python 2 compatibility dropped
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sys.stdout = codecs.getwriter('utf8')(sys.stdout.buffer)
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# The ranges of Unicode characters that we consider to be "plain letters".
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# For now we are being conservative by including only Latin and Greek. This
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# could be extended in future based on feedback from people with relevant
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# language knowledge.
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PLAIN_LETTER_RANGES = ((ord('a'), ord('z')), # Latin lower case
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(ord('A'), ord('Z')), # Latin upper case
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(0x03b1, 0x03c9), # GREEK SMALL LETTER ALPHA, GREEK SMALL LETTER OMEGA
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(0x0391, 0x03a9)) # GREEK CAPITAL LETTER ALPHA, GREEK CAPITAL LETTER OMEGA
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# Combining marks follow a "base" character, and result in a composite
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# character. Example: "U&'A\0300'"produces "À".There are three types of
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# combining marks: enclosing (Me), non-spacing combining (Mn), spacing
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# combining (Mc). We identify the ranges of marks we feel safe removing.
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# References:
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# https://en.wikipedia.org/wiki/Combining_character
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# https://www.unicode.org/charts/PDF/U0300.pdf
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# https://www.unicode.org/charts/PDF/U20D0.pdf
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COMBINING_MARK_RANGES = ((0x0300, 0x0362), # Mn: Accents, IPA
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(0x20dd, 0x20E0), # Me: Symbols
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(0x20e2, 0x20e4),) # Me: Screen, keycap, triangle
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def print_record(codepoint, letter):
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if letter:
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output = chr(codepoint) + "\t" + letter
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else:
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output = chr(codepoint)
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print(output)
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class Codepoint:
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def __init__(self, id, general_category, combining_ids):
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self.id = id
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self.general_category = general_category
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self.combining_ids = combining_ids
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def is_mark_to_remove(codepoint):
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"""Return true if this is a combining mark to remove."""
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if not is_mark(codepoint):
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return False
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for begin, end in COMBINING_MARK_RANGES:
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if codepoint.id >= begin and codepoint.id <= end:
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return True
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return False
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def is_plain_letter(codepoint):
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"""Return true if codepoint represents a "plain letter"."""
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for begin, end in PLAIN_LETTER_RANGES:
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if codepoint.id >= begin and codepoint.id <= end:
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return True
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return False
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def is_mark(codepoint):
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"""Returns true for diacritical marks (combining codepoints)."""
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return codepoint.general_category in ("Mn", "Me", "Mc")
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def is_letter_with_marks(codepoint, table):
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"""Returns true for letters combined with one or more marks."""
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# See https://www.unicode.org/reports/tr44/tr44-14.html#General_Category_Values
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# Letter may have no combining characters, in which case it has
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# no marks.
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if len(codepoint.combining_ids) == 1:
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return False
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# A letter without diacritical marks has none of them.
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if any(is_mark(table[i]) for i in codepoint.combining_ids[1:]) is False:
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return False
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# Check if the base letter of this letter has marks.
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codepoint_base = codepoint.combining_ids[0]
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if (is_plain_letter(table[codepoint_base]) is False and \
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is_letter_with_marks(table[codepoint_base], table) is False):
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return False
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return True
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def is_letter(codepoint, table):
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"""Return true for letter with or without diacritical marks."""
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return is_plain_letter(codepoint) or is_letter_with_marks(codepoint, table)
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def get_plain_letter(codepoint, table):
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"""Return the base codepoint without marks. If this codepoint has more
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than one combining character, do a recursive lookup on the table to
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find out its plain base letter."""
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if is_letter_with_marks(codepoint, table):
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if len(table[codepoint.combining_ids[0]].combining_ids) > 1:
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return get_plain_letter(table[codepoint.combining_ids[0]], table)
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elif is_plain_letter(table[codepoint.combining_ids[0]]):
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return table[codepoint.combining_ids[0]]
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# Should not come here
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assert(False)
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elif is_plain_letter(codepoint):
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return codepoint
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# Should not come here
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assert(False)
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def is_ligature(codepoint, table):
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"""Return true for letters combined with letters."""
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return all(is_letter(table[i], table) for i in codepoint.combining_ids)
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def get_plain_letters(codepoint, table):
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"""Return a list of plain letters from a ligature."""
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assert(is_ligature(codepoint, table))
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return [get_plain_letter(table[id], table) for id in codepoint.combining_ids]
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def parse_cldr_latin_ascii_transliterator(latinAsciiFilePath):
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"""Parse the XML file and return a set of tuples (src, trg), where "src"
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is the original character and "trg" the substitute."""
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charactersSet = set()
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# RegEx to parse rules
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rulePattern = re.compile(r'^(?:(.)|(\\u[0-9a-fA-F]{4})) \u2192 (?:\'(.+)\'|(.+)) ;')
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# construct tree from XML
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transliterationTree = ET.parse(latinAsciiFilePath)
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transliterationTreeRoot = transliterationTree.getroot()
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# Fetch all the transliteration rules. Since release 29 of Latin-ASCII.xml
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# all the transliteration rules are located in a single tRule block with
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# all rules separated into separate lines.
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blockRules = transliterationTreeRoot.findall("./transforms/transform/tRule")
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assert(len(blockRules) == 1)
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# Split the block of rules into one element per line.
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rules = blockRules[0].text.splitlines()
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# And finish the processing of each individual rule.
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for rule in rules:
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matches = rulePattern.search(rule)
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# The regular expression capture four groups corresponding
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# to the characters.
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#
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# Group 1: plain "src" char. Empty if group 2 is not.
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# Group 2: unicode-escaped "src" char (e.g. "\u0110"). Empty if group 1 is not.
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#
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# Group 3: plain "trg" char. Empty if group 4 is not.
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# Group 4: plain "trg" char between quotes. Empty if group 3 is not.
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if matches is not None:
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src = matches.group(1) if matches.group(1) is not None else bytes(matches.group(2), 'UTF-8').decode('unicode-escape')
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trg = matches.group(3) if matches.group(3) is not None else matches.group(4)
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# "'" and """ are escaped
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trg = trg.replace("\\'", "'").replace('\\"', '"')
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# the parser of unaccent only accepts non-whitespace characters
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# for "src" and "trg" (see unaccent.c)
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if not src.isspace() and not trg.isspace():
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charactersSet.add((ord(src), trg))
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return charactersSet
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def special_cases():
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"""Returns the special cases which are not handled by other methods"""
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charactersSet = set()
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# Cyrillic
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charactersSet.add((0x0401, u"\u0415")) # CYRILLIC CAPITAL LETTER IO
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charactersSet.add((0x0451, u"\u0435")) # CYRILLIC SMALL LETTER IO
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# Symbols of "Letterlike Symbols" Unicode Block (U+2100 to U+214F)
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charactersSet.add((0x2103, u"\xb0C")) # DEGREE CELSIUS
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charactersSet.add((0x2109, u"\xb0F")) # DEGREE FAHRENHEIT
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charactersSet.add((0x2117, "(P)")) # SOUND RECORDING COPYRIGHT
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return charactersSet
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def main(args):
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# https://www.unicode.org/reports/tr44/tr44-14.html#Character_Decomposition_Mappings
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decomposition_type_pattern = re.compile(" *<[^>]*> *")
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table = {}
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all = []
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# unordered set for ensure uniqueness
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charactersSet = set()
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# read file UnicodeData.txt
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with codecs.open(
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args.unicodeDataFilePath, mode='r', encoding='UTF-8',
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) as unicodeDataFile:
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# read everything we need into memory
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for line in unicodeDataFile:
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fields = line.split(";")
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if len(fields) > 5:
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# https://www.unicode.org/reports/tr44/tr44-14.html#UnicodeData.txt
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general_category = fields[2]
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decomposition = fields[5]
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decomposition = re.sub(decomposition_type_pattern, ' ', decomposition)
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id = int(fields[0], 16)
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combining_ids = [int(s, 16) for s in decomposition.split(" ") if s != ""]
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codepoint = Codepoint(id, general_category, combining_ids)
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table[id] = codepoint
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all.append(codepoint)
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# walk through all the codepoints looking for interesting mappings
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for codepoint in all:
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if codepoint.general_category.startswith('L') and \
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len(codepoint.combining_ids) > 1:
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if is_letter_with_marks(codepoint, table):
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charactersSet.add((codepoint.id,
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chr(get_plain_letter(codepoint, table).id)))
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elif args.noLigaturesExpansion is False and is_ligature(codepoint, table):
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charactersSet.add((codepoint.id,
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"".join(chr(combining_codepoint.id)
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for combining_codepoint \
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in get_plain_letters(codepoint, table))))
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elif is_mark_to_remove(codepoint):
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charactersSet.add((codepoint.id, None))
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# add CLDR Latin-ASCII characters
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if not args.noLigaturesExpansion:
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charactersSet |= parse_cldr_latin_ascii_transliterator(args.latinAsciiFilePath)
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charactersSet |= special_cases()
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# sort for more convenient display
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charactersList = sorted(charactersSet, key=lambda characterPair: characterPair[0])
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for characterPair in charactersList:
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print_record(characterPair[0], characterPair[1])
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if __name__ == "__main__":
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parser = argparse.ArgumentParser(description='This script builds unaccent.rules on standard output when given the contents of UnicodeData.txt and Latin-ASCII.xml given as arguments.')
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parser.add_argument("--unicode-data-file", help="Path to formatted text file corresponding to UnicodeData.txt.", type=str, required=True, dest='unicodeDataFilePath')
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parser.add_argument("--latin-ascii-file", help="Path to XML file from Unicode Common Locale Data Repository (CLDR) corresponding to Latin-ASCII transliterator (Latin-ASCII.xml).", type=str, dest='latinAsciiFilePath')
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parser.add_argument("--no-ligatures-expansion", help="Do not expand ligatures and do not use Unicode CLDR Latin-ASCII transliterator. By default, this option is not enabled and \"--latin-ascii-file\" argument is required. If this option is enabled, \"--latin-ascii-file\" argument is optional and ignored.", action="store_true", dest='noLigaturesExpansion')
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args = parser.parse_args()
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if args.noLigaturesExpansion is False and args.latinAsciiFilePath is None:
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sys.stderr.write('You must specify the path to Latin-ASCII transliterator file with \"--latin-ascii-file\" option or use \"--no-ligatures-expansion\" option. Use \"-h\" option for help.')
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sys.exit(1)
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main(args)
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