Erlang and Elixir library for performing easy type conversions. The Elixir interface is now a lot more complex than the Erlang one; supporting schema-based conversions between container types along with validation and default values.
The package can be installed by adding want to your list of dependencies
in mix.exs:
def deps do
[{:want, "~> 1.14"}]
endConversion between types in Erlang.
% String to integer
1 = want:integer( "1" ),
% String to float
1.0 = want:float( "1" ),
% Integer to String
"1.0" = want:string( 1 ),
% Integer to binary
<<"1.0">> = want:binary( 1 ),
% String to boolean
true = want:boolean( "true" ),Conversion between types in Elixir.
# String to integer
{:ok, 1} = Want.integer("1")
# String to integer, raise on failure
1 = Want.integer!("1")
# String to float
{:ok, 1.0} = Want.float("1")
# String to float, raise on failure
1.0 = Want.float!("1")
# Integer to string
{:ok, "1"} = Want.string(1)
# Integer to string, raise on failure
"1" = Want.string!(1)
# String to boolean
{:ok, true} = Want.boolean("true")
{:ok, false} = Want.boolean("FALSE")
# String to boolean, raise on failure
true = Want.boolean!("true")# Binary to Integer with default value used on conversion failure
{:ok, 1} = Want.integer("foo", default: 1)
# Map to Keyword List with default values used on conversion failure
{:ok, [id: 1]} = Want.keywords(%{"id" => "bananas"}, %{id: [type: :integer, default: 1]})
# Map to Map with field type conversions
{:ok, %{hello: "world", foo: :bar}} = Want.map(%{"hello" => "world", "foo" => "bar"}, %{hello: [], foo: [type: :atom]})
# Nested Key Extraction
{:ok, %{id: 100}} = Want.Map.cast(%{"a" => %{"b" => %{"c" => 100}}}, %{id: [type: :integer, from: {"a", "b", "c"}]})
# Key extraction from multiple potential fields, first match wins
{:ok, %{id: 100}} = Want.Map.cast(%{"b" => "100", "c" => "200"}, %{id: [type: :integer, from: ["a", "b", "c"]]})It can be useful to define the shape of your data, similar to how Ecto.Schema works; simultaneously defining a struct and
the means to parse it from incoming data. You can use Want.Shape to do this.
defmodule MyModule do
use Want.Shape
shape do
field :is_valid, :boolean, default: false
field :count, :integer, default: 0
field :from, :string, from: "FromField"
field :multi_from, :integer, from: ["a", {"b", "c", "d"}], default: 0
end
end
{:ok, %MyModule{is_valid: true, count: 10, from: "Foo", multi_from: 10}} = MyModule.cast(%{
"is_valid" => "true",
"count" => "10",
"from" => "Foo",
"b" => %{
"c" => %{
"d" => 10
}
}
})