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# number_words.py
#
# Copyright 2020, Paul McGuire
#
# Parser/evaluator for expressions of numbers as written out in words:
# - one
# - seven
# - twelve
# - twenty six
# - forty-two
# - one hundred and seven
#
#
# BNF:
"""
optional_and ::= ["and" | "-"]
optional_dash ::= ["-"]
units ::= one | two | three | ... | nine
teens_only ::= eleven | twelve | ... | nineteen
teens ::= ten | teens_only
tens ::= twenty | thirty | ... | ninety
hundreds ::= (units | teens_only | tens optional_dash units) "hundred"
one_to_99 ::= units | teens | (tens [optional_dash units])
thousands = one_to_99 "thousand"
number = [thousands] [hundreds] optional_and units | [thousands] optional_and hundreds | thousands
"""
import pyparsing as pp
from operator import mul
import pyparsing.diagram
def define_numeric_word(s, value):
return pp.CaselessKeyword(s).addParseAction(lambda: value)
def define_numeric_word_range(s, vals):
if isinstance(s, str):
s = s.split()
return pp.MatchFirst(
define_numeric_word(nm, nm_value) for nm, nm_value in zip(s, vals)
)
opt_dash = pp.Optional(pp.Suppress("-")).setName("optional '-'")
opt_and = pp.Optional((pp.CaselessKeyword("and") | "-").suppress()).setName("optional 'and'")
zero = define_numeric_word_range("zero oh", [0, 0])
one_to_9 = define_numeric_word_range("one two three four five six seven eight nine", range(1, 9 + 1)).setName("1-9")
eleven_to_19 = define_numeric_word_range("eleven twelve thirteen fourteen fifteen sixteen seventeen eighteen nineteen",
range(11, 19 + 1)).setName("eleven_to_19")
ten_to_19 = (define_numeric_word("ten", 10) | eleven_to_19).setName("ten_to_19")
one_to_19 = (one_to_9 | ten_to_19).setName("1-19")
tens = define_numeric_word_range("twenty thirty forty fifty sixty seventy eighty ninety", range(20, 90+1, 10))
hundreds = (one_to_9 | eleven_to_19 | (tens + opt_dash + one_to_9)) + define_numeric_word("hundred", 100)
one_to_99 = (one_to_19 | (tens + pp.Optional(opt_dash + one_to_9)).addParseAction(sum)).setName("1-99")
one_to_999 = ((pp.Optional(hundreds + opt_and) + one_to_99 | hundreds).addParseAction(sum)).setName("1-999")
thousands = one_to_999 + define_numeric_word("thousand", 1000)
hundreds.setName("100s")
thousands.setName("1000s")
def multiply(t):
return mul(*t)
hundreds.addParseAction(multiply)
thousands.addParseAction(multiply)
numeric_expression = (
pp.Optional(thousands + opt_and) + pp.Optional(hundreds + opt_and) + one_to_99
| pp.Optional(thousands + opt_and) + hundreds
| thousands
).setName("numeric_words")
numeric_expression.addParseAction(sum)
if __name__ == "__main__":
numeric_expression.runTests(
"""
one
seven
twelve
twenty six
forty-two
two hundred
twelve hundred
one hundred and eleven
ninety nine thousand nine hundred and ninety nine
nine hundred thousand nine hundred and ninety nine
nine hundred and ninety nine thousand nine hundred and ninety nine
nineteen hundred thousand nineteen hundred and ninety nine
"""
)
# create railroad diagram
numeric_expression.create_diagram("numeric_words_diagram.html", vertical=5)
|
