rdf-ex/lib/rdf/datatypes/decimal.ex
2019-04-29 20:45:06 +02:00

150 lines
3.7 KiB
Elixir

defmodule RDF.Decimal do
@moduledoc """
`RDF.Datatype` for XSD decimal.
"""
use RDF.Datatype, id: RDF.Datatype.NS.XSD.decimal
import RDF.Literal.Guards
alias Elixir.Decimal, as: D
@xsd_integer RDF.Datatype.NS.XSD.integer
@impl RDF.Datatype
def convert(value, opts)
def convert(%D{coef: coef} = value, opts) when coef in ~w[qNaN sNaN inf]a,
do: super(value, opts)
def convert(%D{} = decimal, _),
do: canonical_decimal(decimal)
def convert(value, opts) when is_integer(value),
do: value |> D.new() |> convert(opts)
def convert(value, opts) when is_float(value),
do: value |> D.from_float() |> convert(opts)
def convert(value, opts) when is_binary(value) do
if String.contains?(value, ~w[e E]) do
super(value, opts)
else
case D.parse(value) do
{:ok, decimal} -> convert(decimal, opts)
:error -> super(value, opts)
end
end
end
def convert(value, opts), do: super(value, opts)
@impl RDF.Datatype
def canonical_lexical(value)
def canonical_lexical(%D{sign: sign, coef: :qNaN}),
do: if sign == 1, do: "NaN", else: "-NaN"
def canonical_lexical(%D{sign: sign, coef: :sNaN}),
do: if sign == 1, do: "sNaN", else: "-sNaN"
def canonical_lexical(%D{sign: sign, coef: :inf}),
do: if sign == 1, do: "Infinity", else: "-Infinity"
def canonical_lexical(%D{} = decimal),
do: D.to_string(decimal, :normal)
def canonical_decimal(%D{coef: 0} = decimal),
do: %{decimal | exp: -1}
def canonical_decimal(%D{coef: coef, exp: 0} = decimal),
do: %{decimal | coef: coef * 10, exp: -1}
def canonical_decimal(%D{coef: coef, exp: exp} = decimal)
when exp > 0,
do: canonical_decimal(%{decimal | coef: coef * 10, exp: exp - 1})
def canonical_decimal(%D{coef: coef} = decimal)
when Kernel.rem(coef, 10) != 0,
do: decimal
def canonical_decimal(%D{coef: coef, exp: exp} = decimal),
do: canonical_decimal(%{decimal | coef: Kernel.div(coef, 10), exp: exp + 1})
@impl RDF.Datatype
def cast(literal)
def cast(%RDF.Literal{datatype: datatype} = literal) do
cond do
not RDF.Literal.valid?(literal) ->
nil
is_xsd_decimal(datatype) ->
literal
literal == RDF.false ->
new(0.0)
literal == RDF.true ->
new(1.0)
is_xsd_string(datatype) ->
literal.value
|> new()
|> canonical()
|> validate_cast()
is_number(literal.value) and (is_xsd_integer(datatype) or
is_xsd_double(datatype) or is_xsd_float(datatype)) ->
new(literal.value)
true ->
nil
end
end
def cast(_), do: nil
@impl RDF.Datatype
def equal_value?(left, right), do: RDF.Numeric.equal_value?(left, right)
@impl RDF.Datatype
def compare(left, right), do: RDF.Numeric.compare(left, right)
@doc """
The number of digits in the XML Schema canonical form of the literal value.
"""
def digit_count(%RDF.Literal{datatype: @id} = literal) do
if valid?(literal) do
literal
|> canonical()
|> lexical()
|> String.replace(".", "")
|> String.replace("-", "")
|> String.length()
end
end
def digit_count(%RDF.Literal{datatype: @xsd_integer} = literal),
do: RDF.Integer.digit_count(literal)
@doc """
The number of digits to the right of the decimal point in the XML Schema canonical form of the literal value.
"""
def fraction_digit_count(%RDF.Literal{datatype: @id} = literal) do
if valid?(literal) do
[_, fraction] =
literal
|> canonical()
|> lexical()
|> String.split(".")
String.length(fraction)
end
end
def fraction_digit_count(%RDF.Literal{datatype: @xsd_integer}), do: 0
end