9bfb72b055
Without explicit annotation, some type checkers infer that the type of the 'default' argument can only be type[KeyError]. This was the case in unicodedata_test.py, where pyright disallowed "LTR". This commit adds annotations to avoid this, fixing the issue in the test (and external code dependent on the API). Some of the other functions in this file have the same semantics and suffer from the same type error, and so this fix could also be extended to them as usage requires.
301 lines
8.6 KiB
Python
301 lines
8.6 KiB
Python
from __future__ import annotations
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from fontTools.misc.textTools import byteord, tostr
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import re
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from bisect import bisect_right
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from typing import Literal, TypeVar, overload
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try:
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# use unicodedata backport compatible with python2:
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# https://github.com/fonttools/unicodedata2
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from unicodedata2 import *
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except ImportError: # pragma: no cover
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# fall back to built-in unicodedata (possibly outdated)
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from unicodedata import *
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from . import Blocks, Scripts, ScriptExtensions, OTTags
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__all__ = [
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# names from built-in unicodedata module
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"lookup",
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"name",
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"decimal",
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"digit",
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"numeric",
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"category",
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"bidirectional",
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"combining",
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"east_asian_width",
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"mirrored",
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"decomposition",
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"normalize",
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"unidata_version",
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"ucd_3_2_0",
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# additonal functions
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"block",
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"script",
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"script_extension",
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"script_name",
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"script_code",
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"script_horizontal_direction",
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"ot_tags_from_script",
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"ot_tag_to_script",
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]
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def script(char):
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"""Return the four-letter script code assigned to the Unicode character
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'char' as string.
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>>> script("a")
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'Latn'
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>>> script(",")
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'Zyyy'
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>>> script(chr(0x10FFFF))
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'Zzzz'
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"""
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code = byteord(char)
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# 'bisect_right(a, x, lo=0, hi=len(a))' returns an insertion point which
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# comes after (to the right of) any existing entries of x in a, and it
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# partitions array a into two halves so that, for the left side
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# all(val <= x for val in a[lo:i]), and for the right side
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# all(val > x for val in a[i:hi]).
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# Our 'SCRIPT_RANGES' is a sorted list of ranges (only their starting
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# breakpoints); we want to use `bisect_right` to look up the range that
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# contains the given codepoint: i.e. whose start is less than or equal
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# to the codepoint. Thus, we subtract -1 from the index returned.
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i = bisect_right(Scripts.RANGES, code)
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return Scripts.VALUES[i - 1]
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def script_extension(char):
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"""Return the script extension property assigned to the Unicode character
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'char' as a set of string.
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>>> script_extension("a") == {'Latn'}
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True
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>>> script_extension(chr(0x060C)) == {'Rohg', 'Syrc', 'Yezi', 'Arab', 'Thaa', 'Nkoo'}
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True
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>>> script_extension(chr(0x10FFFF)) == {'Zzzz'}
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True
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"""
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code = byteord(char)
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i = bisect_right(ScriptExtensions.RANGES, code)
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value = ScriptExtensions.VALUES[i - 1]
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if value is None:
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# code points not explicitly listed for Script Extensions
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# have as their value the corresponding Script property value
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return {script(char)}
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return value
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def script_name(code, default=KeyError):
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"""Return the long, human-readable script name given a four-letter
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Unicode script code.
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If no matching name is found, a KeyError is raised by default.
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You can use the 'default' argument to return a fallback value (e.g.
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'Unknown' or None) instead of throwing an error.
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"""
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try:
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return str(Scripts.NAMES[code].replace("_", " "))
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except KeyError:
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if isinstance(default, type) and issubclass(default, KeyError):
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raise
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return default
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_normalize_re = re.compile(r"[-_ ]+")
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def _normalize_property_name(string):
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"""Remove case, strip space, '-' and '_' for loose matching."""
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return _normalize_re.sub("", string).lower()
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_SCRIPT_CODES = {_normalize_property_name(v): k for k, v in Scripts.NAMES.items()}
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def script_code(script_name, default=KeyError):
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"""Returns the four-letter Unicode script code from its long name
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If no matching script code is found, a KeyError is raised by default.
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You can use the 'default' argument to return a fallback string (e.g.
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'Zzzz' or None) instead of throwing an error.
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"""
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normalized_name = _normalize_property_name(script_name)
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try:
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return _SCRIPT_CODES[normalized_name]
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except KeyError:
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if isinstance(default, type) and issubclass(default, KeyError):
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raise
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return default
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# The data on script direction is taken from Harfbuzz source code:
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# https://github.com/harfbuzz/harfbuzz/blob/3.2.0/src/hb-common.cc#L514-L613
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# This in turn references the following "Script_Metadata" document:
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# https://docs.google.com/spreadsheets/d/1Y90M0Ie3MUJ6UVCRDOypOtijlMDLNNyyLk36T6iMu0o
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RTL_SCRIPTS = {
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# Unicode-1.1 additions
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"Arab", # Arabic
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"Hebr", # Hebrew
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# Unicode-3.0 additions
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"Syrc", # Syriac
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"Thaa", # Thaana
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# Unicode-4.0 additions
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"Cprt", # Cypriot
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# Unicode-4.1 additions
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"Khar", # Kharoshthi
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# Unicode-5.0 additions
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"Phnx", # Phoenician
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"Nkoo", # Nko
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# Unicode-5.1 additions
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"Lydi", # Lydian
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# Unicode-5.2 additions
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"Avst", # Avestan
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"Armi", # Imperial Aramaic
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"Phli", # Inscriptional Pahlavi
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"Prti", # Inscriptional Parthian
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"Sarb", # Old South Arabian
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"Orkh", # Old Turkic
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"Samr", # Samaritan
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# Unicode-6.0 additions
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"Mand", # Mandaic
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# Unicode-6.1 additions
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"Merc", # Meroitic Cursive
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"Mero", # Meroitic Hieroglyphs
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# Unicode-7.0 additions
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"Mani", # Manichaean
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"Mend", # Mende Kikakui
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"Nbat", # Nabataean
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"Narb", # Old North Arabian
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"Palm", # Palmyrene
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"Phlp", # Psalter Pahlavi
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# Unicode-8.0 additions
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"Hatr", # Hatran
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"Hung", # Old Hungarian
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# Unicode-9.0 additions
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"Adlm", # Adlam
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# Unicode-11.0 additions
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"Rohg", # Hanifi Rohingya
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"Sogo", # Old Sogdian
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"Sogd", # Sogdian
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# Unicode-12.0 additions
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"Elym", # Elymaic
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# Unicode-13.0 additions
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"Chrs", # Chorasmian
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"Yezi", # Yezidi
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# Unicode-14.0 additions
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"Ougr", # Old Uyghur
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}
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HorizDirection = Literal["RTL", "LTR"]
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T = TypeVar("T")
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@overload
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def script_horizontal_direction(script_code: str, default: T) -> HorizDirection | T:
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...
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@overload
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def script_horizontal_direction(
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script_code: str, default: type[KeyError] = KeyError
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) -> HorizDirection:
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...
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def script_horizontal_direction(
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script_code: str, default: T | type[KeyError] = KeyError
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) -> HorizDirection | T:
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"""Return "RTL" for scripts that contain right-to-left characters
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according to the Bidi_Class property. Otherwise return "LTR".
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"""
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if script_code not in Scripts.NAMES:
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if isinstance(default, type) and issubclass(default, KeyError):
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raise default(script_code)
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return default
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return "RTL" if script_code in RTL_SCRIPTS else "LTR"
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def block(char):
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"""Return the block property assigned to the Unicode character 'char'
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as a string.
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>>> block("a")
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'Basic Latin'
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>>> block(chr(0x060C))
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'Arabic'
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>>> block(chr(0xEFFFF))
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'No_Block'
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"""
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code = byteord(char)
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i = bisect_right(Blocks.RANGES, code)
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return Blocks.VALUES[i - 1]
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def ot_tags_from_script(script_code):
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"""Return a list of OpenType script tags associated with a given
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Unicode script code.
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Return ['DFLT'] script tag for invalid/unknown script codes.
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"""
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if script_code in OTTags.SCRIPT_EXCEPTIONS:
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return [OTTags.SCRIPT_EXCEPTIONS[script_code]]
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if script_code not in Scripts.NAMES:
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return [OTTags.DEFAULT_SCRIPT]
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script_tags = [script_code[0].lower() + script_code[1:]]
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if script_code in OTTags.NEW_SCRIPT_TAGS:
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script_tags.extend(OTTags.NEW_SCRIPT_TAGS[script_code])
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script_tags.reverse() # last in, first out
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return script_tags
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def ot_tag_to_script(tag):
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"""Return the Unicode script code for the given OpenType script tag, or
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None for "DFLT" tag or if there is no Unicode script associated with it.
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Raises ValueError if the tag is invalid.
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"""
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tag = tostr(tag).strip()
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if not tag or " " in tag or len(tag) > 4:
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raise ValueError("invalid OpenType tag: %r" % tag)
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if tag in OTTags.SCRIPT_ALIASES:
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tag = OTTags.SCRIPT_ALIASES[tag]
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while len(tag) != 4:
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tag += str(" ") # pad with spaces
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if tag == OTTags.DEFAULT_SCRIPT:
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# it's unclear which Unicode script the "DFLT" OpenType tag maps to,
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# so here we return None
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return None
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if tag in OTTags.NEW_SCRIPT_TAGS_REVERSED:
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return OTTags.NEW_SCRIPT_TAGS_REVERSED[tag]
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if tag in OTTags.SCRIPT_EXCEPTIONS_REVERSED:
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return OTTags.SCRIPT_EXCEPTIONS_REVERSED[tag]
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# This side of the conversion is fully algorithmic
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# Any spaces at the end of the tag are replaced by repeating the last
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# letter. Eg 'nko ' -> 'Nkoo'.
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# Change first char to uppercase
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script_code = tag[0].upper() + tag[1]
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for i in range(2, 4):
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script_code += script_code[i - 1] if tag[i] == " " else tag[i]
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if script_code not in Scripts.NAMES:
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return None
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return script_code
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