Parser for Dutch natural language time strings

parse_time.py

#!/usr/local/Cellar/python3/3.2.3/bin/python3.2

from pypeg2 import *
import datetime

numbers = [
	"nul",
	"een",
	"twee",
	"drie",
	"vier",
	"vijf",
	"zes",
	"zeven",
	"acht",
	"negen",
	"tien",
	"elf",
	"twaalf",
	"dertien",
	"veertien",
	"vijftien",
	"zestien",
	"zeventien",
	"achttien",
	"negentien",
	"twintig",
	"eenentwintig",
	"tweeëntwintig",
	"drieëntwintig",
	"vierentwintig",
	"vijfentwintig",
	"zesentwintig",
	"zevenentwintig",
	"achtentwintig",
	"negenentwintig",
	"dertig",
	"eenendertig",
	"tweeëndertig",
	"drieëndertig",
	"vierendertig",
	"vijfendertig",
	"zesendertig",
	"zevenendertig",
	"achtendertig",
	"negenendertig",
	"veertig",
	"eenenveertig",
	"tweeënveertig",
	"drieënveertig",
	"vierenveertig",
	"vijfenveertig",
	"zesenveertig",
	"zevenenveertig",
	"achtenveertig",
	"negenenveertig",
	"vijftig",
	"eenenvijftig",
	"tweeënvijftig",
	"drieënvijftig",
	"vierenvijftig",
	"vijfenvijftig",
	"zesenvijftig",
	"zevenenvijftig",
	"achtenvijftig",
	"negenenvijftig",	
	"zestig"	
]

times = [
	"12 56",
	"12:56",
	"twaalf dertig",
	"negen vijftien",
	"kwart voor twee",
	"tien voor twee",
	"drie over half tien",
	"13 uur 52",
	"half drie",
	"zevenenveertig over tien",
	"zeven voor half vier",
	"achttien vijftien",
	"zeven",
	"negen uur",
	"8 uur",
	"achttien uur vijftien"
]

class Number(str):
	grammar = word

class Hours(object):
	grammar = flag("half", K("half")), attr("value", Number), optional("uur")

class SignValue(Keyword):
	grammar = Enum( K("voor"), K("over") )

class Sign(object):
	grammar = attr("value", SignValue)
		
class Minutes(object):
	grammar = attr("value", Number)

class Time(List):
	grammar = [		
		(Minutes, Sign, Hours),
		(Minutes, Sign, Hours),
		(Hours, optional(":"), Minutes),
		Hours
	]

def string_to_int(str):
	if str == "kwart":
		return 15		
	for i in range(0, 60):
		if str == numbers[i]:
			return i
		
	return int(str)

def to_time(thing):
	minutes_str = ""
	hours_str = ""
	half = False
	sign = 1
	
	for element in thing:
		if isinstance(element, Hours):
			hours_str = element.value
			half = element.half
		elif isinstance(element, Minutes):
			minutes_str = element.value
		elif isinstance(element, Sign):
			if element.value == "voor":
				sign = -1

	minutes = 0

	if len(hours_str) > 0:
		minutes = string_to_int(hours_str) * 60

	if half:
		minutes -= 30
		
	if len(minutes_str) > 0:
		minutes += sign * string_to_int(minutes_str)

	hours = minutes // 60
	minutes = minutes - (60 * hours)
	
	today = datetime.date.today() #+ datetime.timedelta(days=1)
	return datetime.datetime.combine(today, datetime.time(hours, minutes))

for time_str in times:
	f = parse(time_str, Time)
	time = to_time(f)
	print(time_str, " => ", time)