#!/bin/env python
"""latex.py
Character translation utilities for LaTeX-formatted text.
Usage:
- unicode(string,'latex')
- ustring.decode('latex')
are both available just by letting "import latex" find this file.
- unicode(string,'latex+latin1')
- ustring.decode('latex+latin1')
where latin1 can be replaced by any other known encoding, also
become available by calling latex.register().
We also make public a dictionary latex_equivalents,
mapping ord(unicode char) to LaTeX code.
D. Eppstein, October 2003.
source: http://aspn.activestate.com/ASPN/Cookbook/Python/Recipe/252124
License: Python license (http://python.org/doc/Copyright.html)
modified for mab2bib 2005/2006 by Henning Hraban Ramm
"""
#from __future__ import generators
import codecs
import re
from sets import Set
def register():
"""Enable encodings of the form 'latex+x' where x describes another encoding.
Unicode characters are translated to or from x when possible, otherwise
expanded to latex.
"""
codecs.register(_registry)
def getregentry():
"""Encodings module API."""
return _registry('latex')
def _registry(encoding):
if encoding == 'latex':
encoding = None
elif encoding.startswith('latex+'):
encoding = encoding[6:]
else:
return None
class Codec(codecs.Codec):
def encode(self,input,errors='strict'):
"""Convert unicode string to latex."""
output = []
for c in input:
if encoding:
try:
output.append(c.encode(encoding))
continue
except:
pass
if ord(c) in latex_equivalents:
output.append(latex_equivalents[ord(c)])
else:
output += ['{\\char', str(ord(c)), '}']
return ''.join(output), len(input)
def decode(self,input,errors='strict'):
"""Convert latex source string to unicode."""
if encoding:
input = unicode(input,encoding,errors)
# Note: we may get buffer objects here.
# It is not permussable to call join on buffer objects
# but we can make them joinable by calling unicode.
# This should always be safe since we are supposed
# to be producing unicode output anyway.
x = map(unicode,_unlatex(input))
return u''.join(x), len(input)
class StreamWriter(Codec,codecs.StreamWriter):
pass
class StreamReader(Codec,codecs.StreamReader):
pass
return (Codec().encode,Codec().decode,StreamReader,StreamWriter)
def _tokenize(tex):
"""Convert latex source into sequence of single-token substrings."""
start = 0
try:
# skip quickly across boring stuff
pos = _stoppers.finditer(tex).next().span()[0]
except StopIteration:
yield tex
return
while 1:
if pos > start:
yield tex[start:pos]
if tex[start] == '\\' and not (tex[pos-1].isdigit() and tex[start+1].isalpha()):
while pos < len(tex) and tex[pos].isspace(): # skip blanks after csname
pos += 1
while pos < len(tex) and tex[pos] in _ignore:
pos += 1 # flush control characters
if pos >= len(tex):
return
start = pos
if tex[pos:pos+2] in {'$$':None, '/~':None}: # protect ~ in urls
pos += 2
elif tex[pos].isdigit():
while pos < len(tex) and tex[pos].isdigit():
pos += 1
elif tex[pos] == '-':
while pos < len(tex) and tex[pos] == '-':
pos += 1
elif tex[pos] != '\\' or pos == len(tex) - 1:
pos += 1
elif not tex[pos+1].isalpha():
pos += 2
else:
pos += 1
while pos < len(tex) and tex[pos].isalpha():
pos += 1
if tex[start:pos] == '\\char' or tex[start:pos] == '\\accent':
while pos < len(tex) and tex[pos].isdigit():
pos += 1
class _unlatex:
"""Convert tokenized tex into sequence of unicode strings. Helper for decode()."""
def __iter__(self):
"""Turn self into an iterator. It already is one, nothing to do."""
return self
def __init__(self,tex):
"""Create a new token converter from a string."""
self.tex = tuple(_tokenize(tex)) # turn tokens into indexable list
self.pos = 0 # index of first unprocessed token
self.lastoutput = 'x' # lastoutput must always be nonempty string
def __getitem__(self,n):
"""Return token at offset n from current pos."""
p = self.pos + n
t = self.tex
return p < len(t) and t[p] or None
def next(self):
"""Find and return another piece of converted output."""
if self.pos >= len(self.tex):
raise StopIteration
nextoutput = self.chunk()
if self.lastoutput[0] == '\\' and self.lastoutput[-1].isalpha() and nextoutput[0].isalpha():
nextoutput = ' ' + nextoutput # add extra space to terminate csname
self.lastoutput = nextoutput
return nextoutput
def chunk(self):
"""Grab another set of input tokens and convert them to an output string."""
for delta,c in self.candidates(0):
if c in _l2u:
self.pos += delta
return unichr(_l2u[c])
elif len(c) == 2 and c[1] == 'i' and (c[0],'\\i') in _l2u:
self.pos += delta # correct failure to undot i
return unichr(_l2u[(c[0],'\\i')])
elif len(c) == 1 and c[0].startswith('\\char') and c[0][5:].isdigit():
self.pos += delta
return unichr(int(c[0][5:]))
# nothing matches, just pass through token as-is
self.pos += 1
return self[-1]
def candidates(self,offset):
"""Generate pairs delta,c where c is a token or tuple of tokens from tex
(after deleting extraneous brackets starting at pos) and delta
is the length of the tokens prior to bracket deletion.
"""
t = self[offset]
if t in _blacklist:
return
elif t == '':
for delta,c in self.candidates(offset+1):
if self[offset+delta+1] == '}':
yield delta+2,c
elif t == '\\mbox':
for delta,c in self.candidates(offset+1):
yield delta+1,c
elif t == '$' and self[offset+2] == '$':
yield 3, (t,self[offset+1],t)
else:
q = self[offset+1]
if q == '' and self[offset+3] == '}':
yield 4, (t,self[offset+2])
elif q:
yield 2, (t,q)
yield 1, t
latex_equivalents = {
0x0009: ' ',
0x000a: '\n',
0x0023: '\#',
0x0026: '\&',
0x00a0: '~',
0x00a1: '!`',
0x00a2: '\\not{c}',
0x00a3: '\\pounds',
0x00a7: '\\S',
0x00a8: '\\"{}',
0x00a9: '\\copyright',
0x00af: '\\={}',
0x00ac: '\\neg',
0x00ad: '\\-',
0x00b0: '\\mbox{$^\\circ$}',
0x00b1: '\\mbox{$\\pm$}',
0x00b2: '\\mbox{$^2$}',
0x00b3: '\\mbox{$^3$}',
0x00b4: "\\'{",
0x00b5: '\\mbox{$\\mu$}',
0x00b6: '\\P',
0x00b7: '\\mbox{$\\cdot$}',
0x00b8: '\\c{}',
0x00b9: '\\mbox{$^1$}',
0x00bf: '?`',
0x00c0: '\\`A',
0x00c1: "\\'A",
0x00c2: '\\^A',
0x00c3: '\\~A',
0x00c4: '\\"A',
0x00c5: '\\AA',
0x00c6: '\\AE',
0x00c7: '\\c{C}',
0x00c8: '\\`E',
0x00c9: "\\'E",
0x00ca: '\\^E',
0x00cb: '\\"E',
0x00cc: '\\`I',
0x00cd: "\\'I",
0x00ce: '\\^I',
0x00cf: '\\"I',
0x00d1: '\\~N',
0x00d2: '\\`O',
0x00d3: "\\'O",
0x00d4: '\\^O',
0x00d5: '\\~O',
0x00d6: '\\"O',
0x00d7: '\\mbox{$\\times$}',
0x00d8: '\\O',
0x00d9: '\\`U',
0x00da: "\\'U",
0x00db: '\\^U',
0x00dc: '\\"U',
0x00dd: "\\'Y",
0x00df: '\\ss',
0x00e0: '\\`a',
0x00e1: "\\'a",
0x00e2: '\\^a',
0x00e3: '\\~a',
0x00e4: '\\"a',
0x00e5: '\\aa',
0x00e6: '\\ae',
0x00e7: '\\c{c}',
0x00e8: '\\`e',
0x00e9: "\\'e",
0x00ea: '\\^e',
0x00eb: '\\"e',
0x00ec: '\\`\\i',
0x00ed: "\\'\\i",
0x00ee: '\\^\\i',
0x00ef: '\\"\\i',
0x00f1: '\\~n',
0x00f2: '\\`o',
0x00f3: "\\'o",
0x00f4: '\\^o',
0x00f5: '\\~o',
0x00f6: '\\"o',
0x00f7: '\\mbox{$\\div$}',
0x00f8: '\\o',
0x00f9: '\\`u',
0x00fa: "\\'u",
0x00fb: '\\^u',
0x00fc: '\\"u',
0x00fd: "\\'y",
0x00ff: '\\"y',
0x0100: '\\=A',
0x0101: '\\=a',
0x0102: '\\u{A}',
0x0103: '\\u{a}',
0x0104: '\\c{A}',
0x0105: '\\c{a}',
0x0106: "\\'C",
0x0107: "\\'c",
0x0108: "\\^C",
0x0109: "\\^c",
0x010a: "\\.C",
0x010b: "\\.c",
0x010c: "\\v{C",
0x010d: "\\v{c",
0x010e: "\\v{D",
0x010f: "\\v{d",
0x0112: '\\=E',
0x0113: '\\=e',
0x0114: '\\u{E}',
0x0115: '\\u{e}',
0x0116: '\\.E',
0x0117: '\\.e',
0x0118: '\\c{E}',
0x0119: '\\c{e}',
0x011a: "\\v{E",
0x011b: "\\v{e",
0x011c: '\\^G',
0x011d: '\\^g',
0x011e: '\\u{G}',
0x011f: '\\u{g}',
0x0120: '\\.G',
0x0121: '\\.g',
0x0122: '\\c{G}',
0x0123: '\\c{g}',
0x0124: '\\^H',
0x0125: '\\^h',
0x0128: '\\~I',
0x0129: '\\~\\i',
0x012a: '\\=I',
0x012b: '\\=\\i',
0x012c: '\\u{I}',
0x012d: '\\u\\i',
0x012e: '\\c{I}',
0x012f: '\\c{i}',
0x0130: '\\.I',
0x0131: '\\i',
0x0132: 'IJ',
0x0133: 'ij',
0x0134: '\\^J',
0x0135: '\\^\\j',
0x0136: '\\c{K}',
0x0137: '\\c{k}',
0x0139: "\\'L",
0x013a: "\\'l",
0x013b: "\\c{L",
0x013c: "\\c{l",
0x013d: "\\v{L",
0x013e: "\\v{l",
0x0141: '\\L',
0x0142: '\\l',
0x0143: "\\'N",
0x0144: "\\'n",
0x0145: "\\c{N",
0x0146: "\\c{n",
0x0147: "\\v{N",
0x0148: "\\v{n",
0x014c: '\\=O',
0x014d: '\\=o',
0x014e: '\\u{O}',
0x014f: '\\u{o}',
0x0150: '\\H{O}',
0x0151: '\\H{o}',
0x0152: '\\OE',
0x0153: '\\oe',
0x0154: "\\'R",
0x0155: "\\'r",
0x0156: "\\c{R",
0x0157: "\\c{r",
0x0158: "\\v{R",
0x0159: "\\v{r",
0x015a: "\\'S",
0x015b: "\\'s",
0x015c: "\\^S",
0x015d: "\\^s",
0x015e: "\\c{S",
0x015f: "\\c{s",
0x0160: "\\v{S",
0x0161: "\\v{s",
0x0162: "\\c{T",
0x0163: "\\c{t",
0x0164: "\\v{T",
0x0165: "\\v{t",
0x0168: "\\~U",
0x0169: "\\~u",
0x016a: "\\=U",
0x016b: "\\=u",
0x016c: "\\u{U",
0x016d: "\\u{u",
0x016e: "\\r{U",
0x016f: "\\r{u",
0x0170: "\\H{U",
0x0171: "\\H{u",
0x0172: "\\c{U",
0x0173: "\\c{u",
0x0174: "\\^W",
0x0175: "\\^w",
0x0176: "\\^Y",
0x0177: "\\^y",
0x0178: '\\"Y',
0x0179: "\\'Z",
0x017a: "\\'Z",
0x017b: "\\.Z",
0x017c: "\\.Z",
0x017d: "\\v{Z",
0x017e: "\\v{z",
0x01c4: "D\\v{Z",
0x01c5: "D\\v{z",
0x01c6: "d\\v{z",
0x01c7: "LJ",
0x01c8: "Lj",
0x01c9: "lj",
0x01ca: "NJ",
0x01cb: "Nj",
0x01cc: "nj",
0x01cd: "\\v{A",
0x01ce: "\\v{a",
0x01cf: "\\v{I",
0x01d0: "\\v\\i",
0x01d1: "\\v{O",
0x01d2: "\\v{o",
0x01d3: "\\v{U",
0x01d4: "\\v{u",
0x01e6: "\\v{G",
0x01e7: "\\v{g",
0x01e8: "\\v{K",
0x01e9: "\\v{k",
0x01ea: "\\c{O",
0x01eb: "\\c{o",
0x01f0: "\\v\\j",
0x01f1: "DZ",
0x01f2: "Dz",
0x01f3: "dz",
0x01f4: "\\'G",
0x01f5: "\\'g",
0x01fc: "\\'\\AE",
0x01fd: "\\'\\ae",
0x01fe: "\\'\\O",
0x01ff: "\\'\\o",
0x02c6: '\\^{}',
0x02dc: '\\~{}',
0x02d8: '\\u{}',
0x02d9: '\\.{}',
0x02da: "\\r{",
0x02dd: '\\H{}',
0x02db: '\\c{}',
0x02c7: '\\v{}',
0x03c0: '\\mbox{$\\pi$}',
# consider adding more Greek here
0xfb01: 'fi',
0xfb02: 'fl',
0x2013: '--',
0x2014: '---',
0x2018: "`",
0x2019: "'",
0x201c: "``",
0x201d: "''",
0x2020: "\\dag",
0x2021: "\\ddag",
0x2122: "\\mbox{$^\\mbox{TM}$",
0x2022: "\\mbox{$\\bullet$",
0x2026: "\\ldots",
0x2202: "\\mbox{$\\partial$",
0x220f: "\\mbox{$\\prod$",
0x2211: "\\mbox{$\\sum$",
0x221a: "\\mbox{$\\surd$",
0x221e: "\\mbox{$\\infty$",
0x222b: "\\mbox{$\\int$",
0x2248: "\\mbox{$\\approx$",
0x2260: "\\mbox{$\\neq$",
0x2264: "\\mbox{$\\leq$",
0x2265: "\\mbox{$\\geq$",
}
for _i in range(0x0020):
if _i not in latex_equivalents:
latex_equivalents[_i] = ''
for _i in range(0x0020,0x007f):
if _i not in latex_equivalents:
latex_equivalents[_i] = chr(_i)
# Characters that should be ignored and not output in tokenization
_ignore = Set([chr(i) for i in range(32)+[127]]) - Set('\t\n\r')
# Regexp of chars not in blacklist, for quick start of tokenize
_stoppers = re.compile('[\x00-\x1f!$\\-?\\{~\\\\`\']')
_blacklist = Set(' \n\r')
_blacklist.add(None) # shortcut candidate generation at end of data
# Construction of inverse translation table
_l2u = {
'\ ':ord(' ') # unexpanding space makes no sense in non-TeX contexts
}
for _tex in latex_equivalents:
if _tex <= 0x0020 or (_tex <= 0x007f and len(latex_equivalents[_tex]) <= 1):
continue # boring entry
_toks = tuple(_tokenize(latex_equivalents[_tex]))
if _toks[0] == '' and _toks[-1] == '}':
_toks = _toks[1:-1]
if _toks[0].isalpha():
continue # don't turn ligatures into single chars
if len(_toks) == 1 and (_toks[0] == "'" or _toks[0] == "`"):
continue # don't turn ascii quotes into curly quotes
if _toks[0] == '\\mbox' and _toks[1] == '' and _toks[-1] == '}':
_toks = _toks[2:-1]
if len(_toks) == 4 and _toks[1] == '' and _toks[3] == '}':
_toks = (_toks[0],_toks[2])
if len(_toks) == 1:
_toks = _toks[0]
_l2u[_toks] = _tex
# Shortcut candidate generation for certain useless candidates:
# a character is in _blacklist if it can not be at the start
# of any translation in _l2u. We use this to quickly skip through
# such characters before getting to more difficult-translate parts.
# _blacklist is defined several lines up from here because it must
# be defined in order to call _tokenize, however it is safe to
# delay filling it out until now.
for i in range(0x0020,0x007f):
_blacklist.add(chr(i))
_blacklist.remove('{')
_blacklist.remove('$')
for candidate in _l2u:
if isinstance(candidate,tuple):
if not candidate or not candidate[0]:
continue
firstchar = candidate[0][0]
else:
firstchar = candidate[0]
_blacklist.discard(firstchar)