# Script to generate CaseConvert.cxx from Python's Unicode data
# Should be run rarely when a Python with a new version of Unicode data is available.
# Should not be run with old versions of Python.
# Current best approach divides case conversions into two cases:
# simple symmetric and complex.
# Simple symmetric is where a lower and upper case pair convert to each
# other and the folded form is the same as the lower case.
# There are 1006 symmetric pairs.
# These are further divided into ranges (stored as lower, upper, range length,
# range pitch and singletons (stored as lower, upper).
# Complex is for cases that don't fit the above: where there are multiple
# characters in one of the forms or fold is different to lower or
# lower(upper(x)) or upper(lower(x)) are not x. These are represented as UTF-8
# strings with original, folded, upper, and lower separated by '|'.
# There are 126 complex cases.
import codecs, itertools, os, string, sys, unicodedata
from FileGenerator import Regenerate
def contiguousRanges(l, diff):
# l is s list of lists
# group into lists where first element of each element differs by diff
out = [[l]]
for s in l[1:]:
if s != out[-1][-1] + diff:
"Flatten one level of nesting"
# For all Unicode characters, see whether they have case conversions
# Return 2 sets: one of simple symmetric conversion cases and another
# with complex cases.
complexes = 
symmetrics = 
for ch in range(sys.maxunicode):
if ch >= 0xd800 and ch <= 0xDBFF:
if ch >= 0xdc00 and ch <= 0xDFFF:
uch = chr(ch)
fold = uch.casefold()
upper = uch.upper()
lower = uch.lower()
symmetric = False
if uch != upper and len(upper) == 1 and uch == lower and uch == fold:
lowerUpper = upper.lower()
foldUpper = upper.casefold()
if lowerUpper == foldUpper and lowerUpper == uch:
symmetric = True
symmetrics.append((ch, ord(upper), ch - ord(upper)))
if uch != lower and len(lower) == 1 and uch == upper and lower == fold:
upperLower = lower.upper()
if upperLower == uch:
symmetric = True
if fold == uch:
fold = ""
if upper == uch:
upper = ""
if lower == uch:
lower = ""
if (fold or upper or lower) and not symmetric:
complexes.append((uch, fold, upper, lower))
return symmetrics, complexes
# Group the symmetrics into groups where possible, returning a list
# of ranges and a list of symmetrics that didn't fit into a range
groups = 
uniquekeys = 
for k, g in itertools.groupby(symmetrics, distance):
groups.append(list(g)) # Store group iterator as a list
contiguousGroups = flatten([contiguousRanges(g, 1) for g in groups])
longGroups = [(x, x, len(x), 1) for x in contiguousGroups if len(x) > 4]
oneDiffs = [s for s in symmetrics if s == 1]
contiguousOnes = flatten([contiguousRanges(g, 2) for g in [oneDiffs]])
longOneGroups = [(x, x, len(x), 2) for x in contiguousOnes if len(x) > 4]
rangeGroups = sorted(longGroups+longOneGroups, key=lambda s: s)
rangeCoverage = list(flatten([range(r, r+r*r, r) for r in rangeGroups]))
nonRanges = [(l, u) for l, u, d in symmetrics if l not in rangeCoverage]
return rangeGroups, nonRanges
symmetrics, complexes = conversionSets()
rangeGroups, nonRanges = groupRanges(symmetrics)
rangeLines = ["%d,%d,%d,%d, " % x for x in rangeGroups]
print(len(nonRanges), "non ranges")
nonRangeLines = ["%d,%d, " % x for x in nonRanges]
complexLines = ['"%s|%s|%s|%s|"' % x for x in complexes]
Regenerate("../src/CaseConvert.cxx", "//", rangeLines, nonRangeLines, complexLines)