Convert numbers to number words in a number of languages. Each language has its own module. The module name is based on the ISO 639-3 code for that language. Each module contains one or more functions to convert numerical values to numerals. Several types of numerals are supported. But not every type is supported by every language. Some because they do not occur in that language. Others because they are not yet defined in this package.
Describe quantity - one, two, three, etc.
Describe position in a sequential order - first, second, third, etc.
Describe division into fractions - two thirds, three quarters.
Describe repetition, how many time - once, twice, thrice.
In some languages number words are modified based on a number of grammatical categories such as gender or number. For instance, in Spanish, the numeral for the quantity '1' can be one of uno, un or una depending on whether it is of the neuter, masculine or feminine gender. In order to support this process every conversion function takes an inflection parameter which defines the grammatical state.
Inflections are not concrete types, but polymorphic parameters
constrained by type classes. Use the reified inflection type provided
numerals-base package to get a concrete value:
>>> import Text.Numeral.Grammar.Reified ( defaultInflection )
struct functions convert numbers to a polymorphic representation
of their grammatical structure. They are found in every language
The use of this package is best understood with some examples. First some English number names, both British and US variants:
>>> import qualified Text.Numeral.Language.ENG as ENG >>> ENG.gb_cardinal defaultInflection 123 :: Maybe Text Just "one hundred and twenty-three" >>> ENG.us_cardinal defaultInflection (10^50 + 42) :: Maybe Text Just "one hundred quindecillion forty-two"
French, which contains some traces of a base 20 system:
>>> import qualified Text.Numeral.Language.FRA as FRA >>> FRA.cardinal defaultInflection (-99) :: Maybe Text Just "moins quatre-vingt-dix-neuf"
Conversions can fail. Alamblak, a language spoken by a few people in Papua New Guinea, has no representation for negative numbers:
>>> import qualified Text.Numeral.Language.AMP as AMP >>> AMP.cardinal defaultInflection (-3) :: Maybe Text Nothing
Some languages have multiple scripts and methods for writing number names. Take Chinese for example, which can be written using Han characters or transcribed to the Latin script using Pinyin.
Traditional Chinese characters:
>>> import qualified Text.Numeral.Language.ZHO as ZHO >>> ZHO.trad_cardinal defaultInflection 123456 :: Maybe Text Just "十二萬三千四百五十六"
Simplified characters for use in financial contexts:
>>> ZHO.finance_simpl_cardinal defaultInflection 123456 :: Maybe Text Just "拾贰万参仟肆伯伍拾陆"
Transcribed using Pinyin:
>>> ZHO.pinyin_cardinal defaultInflection 123456 :: Maybe Texto Just "shíèrwàn sānqiān sìbǎi wǔshí liù"
In Spanish the word for the quantity '1' differs based on its gender. We convey the gender via the inflection parameter:
>>> import Text.Numeral.Grammar ( masculine, feminine, neuter ) >>> import Text.Numeral.Grammar ( defaultInflection ) >>> import qualified Text.Numeral.Language.SPA as SPA >>> SPA.cardinal (masculine defaultInflection) 1 :: Maybe Text Just "un" >>> SPA.cardinal (feminine defaultInflection) 1 :: Maybe Text Just "una" >>> SPA.cardinal (neuter defaultInflection) 1 :: Maybe Text Just "uno"
struct functions you can see the grammatical structure of
number names. Because the results of these functions are polymorphic
you need to specify a specific type.
>>> import qualified Text.Numeral.Language.NLD as NLD >>> import Text.Numeral.Exp ( Exp, showExp ) >>> showExp (NLD.struct 123 :: Exp Add (Lit 100) (Add (Lit 3) (Mul (Lit 2) (Lit 10)))
>>> NLD.cardinal defaultInflection 123 :: Maybe Text Just "honderddrieëntwintig"
100 (honderd) + (3 (drie) + (ën) 2 (twin) * 10 (tig))