# `Localize.Number.Parser.Amount`
[🔗](https://github.com/elixir-localize/localize/blob/v1.5.0/lib/localize/number/parser/amount.ex#L1)

The grammar of a currency amount, read from the tokens of
`Localize.Number.Lexer`, behind
`Localize.Number.Parser.parse_currency_amount/2`.

An amount is a number with currency text before it or after it,
inside the signs, parentheses and spaces that decorate the number.
The grammar finds the two; the rules below decide what the currency
text names, which separators the number is read with, and when an
amount that could be read two ways is refused instead.

## Grammar

```ebnf
amount    = outer, [ currency ], inner, number, closing, [ currency ], outer ;
currency  = text, [ mark ] ;
number    = digits, { mark | space | digits } ;
outer     = { space | tab | sign | "(" | ")" } ;
inner     = outer ;
closing   = { space | tab | sign | "(" | ")" | mark | dash } ;
```

with at most one `currency`. `number` is the text from the first
digit to the last, which `Localize.Number.Parser.parse/2` then reads
with the currency's separators. A `mark` that ends the currency text
before the digits ("$.50", "kr.5") is the currency's where CLDR
writes the currency with it, the number's where it is the currency's
decimal mark, and otherwise refused (`amount_currency/3`).

The rules, each a named function:

* **Currency text** names a currency only where one alone takes it,
  after NFKC normalization, with a trailing period tried off as well
  as on (`text_currency/2`).

* **A caller's currencies** (`:caller_currency`) take text the locale
  does not name; text naming both a CLDR currency and a different one
  of the caller's is refused, except in a locale whose own currency
  it names (`unclaimed_currency/3`, `uncontested_caller_currency/3`).

* **A caller's word with digits in it**, such as a digital token
  identifier, is the first word or the last, and is read only where
  the amount has no other reading (`caller_word_amounts/3`,
  `one_reading/3`).

* **No currency** is the `:default_currency`, or a missing-currency
  error (`amount_currency/3`).

* **The number** is read with the currency's separators and
  `grouping: :sizes`, and three fraction digits in a currency of fewer
  places are refused as a possible thousands group
  (`amount_number/4`, `unambiguous_fraction/3`).

---

*Consult [api-reference.md](api-reference.md) for complete listing*