Re: ERROR: functions in index expression must be marked IMMUTABLE

On 03.03.2017 11:43, Geoff Winkless wrote:
> ​One alternative would be to make to_date accept all language variants
> of months simultaneously. A quick search of google suggests that there
> aren't any overlaps between languages (ie where one language uses
> "Foo" for March and another uses "Foo" for May), although you would
> have to​ do some more intense research to be sure. As far as I can see
> there's no other reason why to_date would need to be marked as
> stable/volatile, is there?

As a side-note, it seems there are overlapping short months:

Using
this webpage http://web.library.yale.edu/cataloging/months.htm
this JS(Firefox) JSON.stringify([for (x of
document.querySelectorAll('table.grid tr td')) x.textContent])
this Python

import pprint
from collections import defaultdict

def chunks(l, n):
"""Yield successive n-sized chunks from l."""
for i in range(0, len(l), n):
yield l[i:i + n]

a=<json output from Firefox>
a=list(chunks(a, 13))

dd=defaultdict(list)
for l in a:
for i, m in enumerate(l):
if i == 0:
continue
dd[m].append((i, l[0]))

pprint.pprint(dict(dd))
{'\nmart\n': [(3, 'Serbian')],
'Ag.': [(8, 'Indonesian')],
'Agustos': [(8, 'Turkish')],
'Apr': [(4, 'Latin')],
'Apr.': [(4, 'English'),
(4, 'German'),
(4, 'Greek, Modern'),
(4, 'Indonesian'),
(4, 'Malaysian'),
(4, 'Romanian')],
'Aralik': [(12, 'Turkish')],
'Aug.': [(8, 'English'),
(8, 'German'),
(8, 'Greek, Modern'),
(8, 'Latin'),
(8, 'Romanian')],
'Awst': [(8, 'Welsh')],
'Chwef.': [(2, 'Welsh')],
'Dec.': [(12, 'English'), (12, 'Latin'), (12, 'Romanian')],
'Dek.': [(12, 'Greek, Modern')],
'Des.': [(12, 'Indonesian')],
'Dez.': [(12, 'German')],
'Dis.': [(12, 'Malaysian')],
'Ebr.': [(4, 'Welsh')],
'Ekim': [(10, 'Turkish')],
'Eylul': [(9, 'Turkish')],
'Feb.': [(2, 'English'), (2, 'German'), (2, 'Malaysian'), (2,
'Romanian')],
'Febr.': [(2, 'Latin')],
'Gorff.': [(7, 'Welsh')],
'Haziran': [(6, 'Turkish')],
'Hyd.': [(10, 'Welsh')],
'Ian.': [(1, 'Greek, Modern'), (1, 'Latin'), (1, 'Romanian')],
'Ion.': [(1, 'Welsh')],
'Ioul.': [(7, 'Greek, Modern')],
'Ioun.': [(6, 'Greek, Modern')],
'Iul.': [(7, 'Latin')],
'Iulie': [(7, 'Romanian')],
'Iun.': [(6, 'Latin')],
'Iunie': [(6, 'Romanian')],
'Jan.': [(1, 'English'), (1, 'Malaysian')],
'Jan./Djan.\xc2\xa0': [(1, 'Indonesian')],
'Jan./J\xc3\xa4n.': [(1, 'German')],
'Julai': [(7, 'Malaysian')],
'Juli': [(7, 'German')],
'Juli/Djuli': [(7, 'Indonesian')],
'July': [(7, 'English')],
'Jun': [(6, 'Malaysian')],
'June': [(6, 'English')],
'Juni': [(6, 'German')],
'Juni/Djuni': [(6, 'Indonesian')],
'Kasim': [(11, 'Turkish')],
'Mac': [(3, 'Malaysian')],
'Mai': [(5, 'German'), (5, 'Romanian'), (5, 'Welsh')],
'Mai.': [(5, 'Latin')],
'Maios': [(5, 'Greek, Modern')],
'Mar.': [(3, 'English'), (3, 'Romanian')],
'Mart.': [(3, 'Greek, Modern'), (3, 'Latin')],
'Maw.': [(3, 'Welsh')],
'May': [(5, 'English')],
'Mayis': [(5, 'Turkish')],
'Medi': [(9, 'Welsh')],
'Meh.': [(6, 'Welsh')],
'Mei': [(5, 'Malaysian')],
'Mei/Mai': [(5, 'Indonesian')],
'Mrt.': [(3, 'Indonesian')],
'M\xc3\xa4rz': [(3, 'German')],
'Nisan': [(4, 'Turkish')],
'Noem.': [(11, 'Greek, Modern')],
'Noiem.': [(11, 'Romanian')],
'Nop.': [(11, 'Indonesian')],
'Nov.': [(11, 'English'), (11, 'German'), (11, 'Latin'), (11,
'Malaysian')],
'Ocak': [(1, 'Turkish')],
'Oct.': [(10, 'English'), (10, 'Latin'), (10, 'Romanian')],
'Og': [(8, 'Malaysian')],
'Okt.': [(10, 'German'),
(10, 'Greek, Modern'),
(10, 'Indonesian'),
(10, 'Malaysian')],
'Peb.': [(2, 'Indonesian')],
'Phevr.': [(2, 'Greek, Modern')],
'Rhag.': [(12, 'Welsh')],
'Saus.': [(1, 'Lithuanian')],
'Sept.': [(9, 'English'),
(9, 'German'),
(9, 'Greek, Modern'),
(9, 'Indonesian'),
(9, 'Latin'),
(9, 'Malaysian'),
(9, 'Romanian')],
'Subat': [(2, 'Turkish')],
'Tach.': [(11, 'Welsh')],
'Temmuz': [(7, 'Turkish')],
'abr.': [(4, 'Spanish')],
'abril': [(4, 'Portuguese')],
'ag.': [(8, 'Italian')],
'agosto': [(8, 'Portuguese'), (8, 'Spanish')],
'ao\xc3\xbbt': [(8, 'French')],
'apr.': [(4, 'Dutch'),
(4, 'Estonian'),
(4, 'Italian'),
(4, 'Latvian'),
(4, 'Russian')],
'apr./mali traven': [(4, 'Slovenian')],
'april': [(4, 'Bosnian'),
(4, 'Bulgarian'),
(4, 'Danish'),
(4, 'Norwegian'),
(4, 'Serbian'),
(4, 'Swedish')],
'aug.': [(8, 'Bosnian'),
(8, 'Danish'),
(8, 'Dutch'),
(8, 'Estonian'),
(8, 'Hungarian'),
(8, 'Latvian'),
(8, 'Norwegian'),
(8, 'Swedish')],
'avg.': [(8, 'Bulgarian'), (8, 'Russian'), (8, 'Serbian')],
'avg./veliki\xc2\xa0srpan': [(8, 'Slovenian')],
'avril': [(4, 'French')],
'bal.': [(4, 'Lithuanian')],
'ber.': [(3, 'Ukranian')],
'birz': [(6, 'Lithuanian')],
'brez.': [(3, 'Czech')],
'brez./mar.': [(3, 'Slovak')],
'cerv.': [(6, 'Czech')],
'cerv./j\xc3\xban': [(6, 'Slovak')],
'cerven.': [(7, 'Czech')],
'cerven./j\xc3\xbal': [(7, 'Slovak')],
'cher.': [(6, 'Ukranian')],
'cherv.': [(6, 'Belorusian')],
'czerw.': [(6, 'Polish')],
'dec.': [(12, 'Danish'),
(12, 'Dutch'),
(12, 'Hungarian'),
(12, 'Latvian'),
(12, 'Serbian'),
(12, 'Swedish')],
'dec./gr.': [(12, 'Slovenian')],
'dec.\xc2\xa0': [(12, 'Bosnian')],
'dek.': [(12, 'Bulgarian'), (12, 'Russian')],
'des.': [(12, 'Norwegian')],
'dets.': [(12, 'Estonian')],
'dez.': [(12, 'Portuguese')],
'dic.': [(12, 'Italian'), (12, 'Spanish')],
'dub.': [(4, 'Czech')],
'dub./apr.': [(4, 'Slovak')],
'd\xc3\xa9c.': [(12, 'French')],
'enero': [(1, 'Spanish')],
'feb.': [(2, 'Bosnian'),
(2, 'Dutch'),
(2, 'Hungarian'),
(2, 'Latvian'),
(2, 'Spanish')],
'feb./svec.': [(2, 'Slovenian')],
'febbr.': [(2, 'Italian')],
'febr.': [(2, 'Danish'), (2, 'Norwegian'), (2, 'Serbian'), (2,
'Swedish')],
'fev.': [(2, 'Portuguese')],
'fevr.': [(2, 'Bulgarian'), (2, 'Russian')],
'f\xc3\xa9vr.': [(2, 'French')],
'geg.': [(5, 'Lithuanian')],
'genn.': [(1, 'Italian')],
'giugno': [(6, 'Italian')],
'gr.': [(12, 'Lithuanian')],
'grudz.': [(12, 'Polish')],
'hrud.': [(12, 'Ukranian')],
'ian.': [(1, 'Bulgarian')],
'ianv.': [(1, 'Russian')],
"iiul'": [(7, 'Russian')],
"iiun'": [(6, 'Russian')],
'iuli': [(7, 'Bulgarian')],
'iuni': [(6, 'Bulgarian')],
'jaan.': [(1, 'Estonian')],
'jan.': [(1, 'Bosnian'),
(1, 'Danish'),
(1, 'Dutch'),
(1, 'Hungarian'),
(1, 'Latvian'),
(1, 'Norwegian'),
(1, 'Portuguese'),
(1, 'Serbian'),
(1, 'Swedish')],
'jan./pros.': [(1, 'Slovenian')],
'janv.': [(1, 'French')],
'juil.': [(7, 'French')],
'juin': [(6, 'French')],
'jul.': [(7, 'Hungarian'), (7, 'Spanish')],
'jul./mali srpan': [(7, 'Slovenian')],
'julho': [(7, 'Portuguese')],
'juli': [(7, 'Bosnian'),
(7, 'Danish'),
(7, 'Dutch'),
(7, 'Norwegian'),
(7, 'Serbian'),
(7, 'Swedish')],
'julijs': [(7, 'Latvian')],
'jun.': [(6, 'Hungarian'), (6, 'Spanish')],
'jun./roz.': [(6, 'Slovenian')],
'junho': [(6, 'Portuguese')],
'juni': [(6, 'Bosnian'),
(6, 'Danish'),
(6, 'Dutch'),
(6, 'Norwegian'),
(6, 'Serbian'),
(6, 'Swedish')],
'junijs': [(6, 'Latvian')],
'juuli': [(7, 'Estonian')],
'juuni': [(6, 'Estonian')],
'kastr.': [(10, 'Belorusian')],
'kol.': [(8, 'Croatian')],
'kovas': [(3, 'Lithuanian')],
'kras.': [(4, 'Belorusian')],
'kvet.': [(5, 'Czech')],
'kvet/m\xc3\xa1j': [(5, 'Slovak')],
'kvit.': [(4, 'Ukranian')],
'kwiec.': [(4, 'Polish')],
"l'ad./jan.": [(1, 'Slovak')],
'lapkr.': [(11, 'Lithuanian')],
'led.': [(1, 'Czech')],
'liepa': [(7, 'Lithuanian')],
'lip.': [(7, 'Belorusian'), (6, 'Croatian'), (7, 'Polish')],
'list.': [(11, 'Belorusian'), (10, 'Croatian'), (11, 'Czech')],
'list./nov.': [(11, 'Slovak')],
'listop.': [(11, 'Polish')],
'liut.': [(2, 'Belorusian'), (2, 'Ukranian')],
'luglio': [(7, 'Italian')],
'luty': [(2, 'Polish')],
'lyp.': [(7, 'Ukranian')],
'lyst.': [(11, 'Ukranian')],
'maart': [(3, 'Dutch')],
'magg.': [(5, 'Italian')],
'mai': [(5, 'Bulgarian'),
(5, 'Estonian'),
(5, 'French'),
(5, 'Norwegian'),
(5, 'Russian')],
'maijs': [(5, 'Latvian')],
'maio': [(5, 'Portuguese')],
'maj': [(5, 'Bosnian'),
(5, 'Danish'),
(5, 'Polish'),
(5, 'Serbian'),
(5, 'Swedish')],
'maj./veliki traven': [(5, 'Slovenian')],
'mar.': [(3, 'Italian'), (3, 'Polish')],
'mar./sus.': [(3, 'Slovenian')],
'mars': [(3, 'French'), (3, 'Norwegian'), (3, 'Swedish')],
'mart': [(3, 'Bosnian'), (3, 'Bulgarian'), (3, 'Russian'), (3,
'Turkish')],
'marts': [(3, 'Danish'), (3, 'Latvian')],
'marzo': [(3, 'Spanish')],
'mar\xc3\xa7o': [(3, 'Portuguese')],
'mayo': [(5, 'Spanish')],
'mei': [(5, 'Dutch')],
'm\xc3\xa1j.': [(5, 'Hungarian')],
'm\xc3\xa1rc.': [(3, 'Hungarian')],
'm\xc3\xa4rts': [(3, 'Estonian')],
'noem.': [(11, 'Bulgarian')],
"noiabr'": [(11, 'Russian')],
'nov.': [(11, 'Bosnian'),
(11, 'Danish'),
(11, 'Dutch'),
(11, 'Estonian'),
(11, 'French'),
(11, 'Hungarian'),
(11, 'Italian'),
(11, 'Latvian'),
(11, 'Norwegian'),
(11, 'Portuguese'),
(11, 'Serbian'),
(11, 'Spanish'),
(11, 'Swedish')],
'nov./list.': [(11, 'Slovenian')],
'oct.': [(10, 'French'), (10, 'Spanish')],
'oct./okt.': [(10, 'Dutch')],
'okt.': [(10, 'Bosnian'),
(10, 'Bulgarian'),
(10, 'Danish'),
(10, 'Estonian'),
(10, 'Hungarian'),
(10, 'Latvian'),
(10, 'Norwegian'),
(10, 'Russian'),
(10, 'Serbian'),
(10, 'Swedish')],
'okt./vino.': [(10, 'Slovenian')],
'ott.': [(10, 'Italian')],
'out.': [(10, 'Portuguese')],
'ozuj.': [(3, 'Croatian')],
'pazdz.': [(10, 'Polish')],
'pros.': [(12, 'Croatian'), (12, 'Czech')],
'pros./dec.': [(12, 'Slovak')],
'rugp.': [(8, 'Lithuanian')],
'rugs.': [(9, 'Lithuanian')],
'ruj.': [(9, 'Croatian')],
'ruj./okt.': [(10, 'Slovak')],
'r\xc3\xadj.': [(10, 'Czech')],
'sak./mar.': [(3, 'Belorusian')],
'sent.': [(9, 'Russian')],
'sept.': [(9, 'Bosnian'),
(9, 'Bulgarian'),
(9, 'Danish'),
(9, 'Dutch'),
(9, 'Estonian'),
(9, 'French'),
(9, 'Latvian'),
(9, 'Norwegian'),
(9, 'Serbian'),
(9, 'Swedish')],
'sept./kim.': [(9, 'Slovenian')],
'sept./set.': [(9, 'Spanish')],
'serp.': [(8, 'Ukranian')],
'set.': [(9, 'Portuguese')],
'sett.': [(9, 'Italian')],
'sich.': [(1, 'Ukranian')],
'sierp.': [(8, 'Polish')],
'sijec.': [(1, 'Croatian')],
'snezh.': [(12, 'Belorusian')],
'spalis': [(10, 'Lithuanian')],
'srp.': [(7, 'Croatian'), (8, 'Czech')],
'srp./aug.': [(8, 'Slovak')],
'stud.': [(11, 'Croatian')],
'studz.': [(1, 'Belorusian')],
'stycz.': [(1, 'Polish')],
'svib.': [(5, 'Croatian')],
'szept.': [(9, 'Hungarian')],
'trav.': [(5, 'Belorusian'), (4, 'Croatian'), (5, 'Ukranian')],
'vas.': [(2, 'Lithuanian')],
'veebr.': [(2, 'Estonian')],
'velj.': [(2, 'Croatian')],
'ver.': [(9, 'Ukranian')],
'veras.': [(9, 'Belorusian')],
'wrzes.': [(9, 'Polish')],
"zhniven'": [(8, 'Belorusian')],
'zhovt.': [(10, 'Ukranian')],
'z\xc3\xa1r.': [(9, 'Czech')],
'z\xc3\xa1ri./sept.': [(9, 'Slovak')],
'\xc3\xa1pr.': [(4, 'Hungarian')],
'\xc3\xban.': [(2, 'Czech')],
'\xc3\xban./feb.': [(2, 'Slovak')]}

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