A simple and concise way to annotate structs (or exceptions) with type info.
The package can be installed by adding ex_type_struct to your list of dependencies in mix.exs:
def deps do
[
{:ex_type_struct, "~> 0.1"}
]
enddefmodule MyStruct do
use ExTypeStruct do
# this is a required field
required_field :: required_field_type()
# this is an optional field
optional_field :: optional_field_type() \\ default_value()
# ^^^ required and optional fields are distinguished by if they have default value.
end
end
defmodule MyException do
use ExTypeStruct.Exception do
# this is a required field
required_field :: required_field_type()
# this is an optional field
optional_field :: optional_field_type() \\ default_value()
# ^^^ required and optional fields are distinguished by if they have default value.
end
end- Use
do ... endblock to contain a list of required / optional fields. - Required fields must have form
field_name :: field_type. - Required fields would be added to
@enforce_keysautomatically. - Optional fields must have form
field_name :: field_type \\ default_value. - Optional fields won't be added to
@enforce_keys.
defmodule MyStruct do
use ExTypeStruct do
end
end
# above code would be compiled / transformed to following code:
defmodule MyStruct do
@enforce_keys []
defstruct []
@type t() :: %__MODULE__{}
enddefmodule MyStruct do
use ExTypeStruct do
name :: String.t()
age :: integer()
end
end
# above code would be compiled / transformed to following code:
defmodule MyStruct do
@enforce_keys [:name, :age]
defstruct [name: nil, age: nil]
@type t() :: %__MODULE__{
name: String.t(),
age: integer()
}
enddefmodule MyStruct do
use ExTypeStruct do
name :: String.t() \\ "Hello"
age :: integer() \\ 123
end
end
# above code would be compiled / transformed to following code:
defmodule MyStruct do
@enforce_keys []
defstruct [name: "Hello", age: 123]
@type t() :: %__MODULE__{
name: String.t(),
age: integer()
}
enddefmodule MyStruct do
use ExTypeStruct do
name :: String.t()
age :: integer() \\ 123
end
end
# above code would be compiled / transformed to following code:
defmodule MyStruct do
@enforce_keys [:name]
defstruct [name: nil, age: 123]
@type t() :: %__MODULE__{
name: String.t(),
age: integer()
}
endBy putting custom type attribute as first expr in do block, it would override default @type t() type attribute.
defmodule MyStruct do
use ExTypeStruct do
@opaque t()
name :: String.t()
age :: integer() \\ 123
end
end
# above code would be compiled / transformed to following code:
defmodule MyStruct do
@enforce_keys [:name]
defstruct [name: nil, age: 123]
@opaque t() :: %__MODULE__{
name: String.t(),
age: integer()
}
endBy putting custom type attribute as first expr in do block, it would override default @type t() type attribute.
defmodule MyStruct do
use ExTypeStruct do
@type t_alias()
name :: String.t()
age :: integer() \\ 123
end
end
# above code would be compiled / transformed to following code:
defmodule MyStruct do
@enforce_keys [:name]
defstruct [name: nil, age: 123]
@type t_alias() :: %__MODULE__{
name: String.t(),
age: integer()
}
endBy putting custom type attribute as first expr in do block, it would override default @type t() type attribute.
defmodule MyStruct do
use ExTypeStruct do
@type t(x, y)
name :: x
age :: y \\ 123
end
end
# above code would be compiled / transformed to following code:
defmodule MyStruct do
@enforce_keys [:name]
defstruct [name: nil, age: 123]
@type t(x, y) :: %__MODULE__{
name: x,
age: y
}
endNothing special. Just like regular defstruct use case.
defmodule MyStruct do
@typedoc "this is type doc"
@drive [MyProtocol]
use ExTypeStruct do
name :: String.t()
age :: integer() \\ 123
end
end
# above code would be compiled / transformed to following code:
defmodule MyStruct do
@typedoc "this is type doc"
@drive [MyProtocol]
@enforce_keys [:name]
defstruct [name: nil, age: 123]
@type t() :: %__MODULE__{
name: String.t(),
age: integer()
}
enddefmodule MyException do
use ExTypeStruct.Exception do
message :: String.t()
end
end
# above code would be compiled / transformed to following code:
defmodule MyException do
@enforce_keys [:message]
defexception [message: nil]
@type t :: %__MODULE__{
message: String.t()
}
endMIT
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