diff options
Diffstat (limited to 'lib/elixir/lib/protocol.ex')
| -rw-r--r-- | lib/elixir/lib/protocol.ex | 55 |
1 files changed, 26 insertions, 29 deletions
diff --git a/lib/elixir/lib/protocol.ex b/lib/elixir/lib/protocol.ex index b39f61922..9e764a551 100644 --- a/lib/elixir/lib/protocol.ex +++ b/lib/elixir/lib/protocol.ex @@ -191,15 +191,17 @@ defmodule Protocol do iex> Enumerable.impl_for(42) nil - In addition, every protocol implementation module contains the `__impl__/1` function. The - function takes one of the following atoms: + In addition, every protocol implementation module contains the `__impl__/1` + function. The function takes one of the following atoms: - * `:for` - returns the module responsible for the data structure of the protocol implementation + * `:for` - returns the module responsible for the data structure of the + protocol implementation - * `:protocol` - returns the protocol module for which this implementation is provided + * `:protocol` - returns the protocol module for which this implementation + is provided - For example, the module implementing the `Enumerable` protocol for lists is `Enumerable.List`. - Therefore, we can invoke `__impl__/1` on this module: + For example, the module implementing the `Enumerable` protocol for lists is + `Enumerable.List`. Therefore, we can invoke `__impl__/1` on this module: iex(1)> Enumerable.List.__impl__(:for) List @@ -209,22 +211,17 @@ defmodule Protocol do ## Consolidation - In order to cope with code loading in development, protocols in - Elixir provide a slow implementation of protocol dispatching specific - to development. - - In order to speed up dispatching in production environments, where - all implementations are known up-front, Elixir provides a feature - called *protocol consolidation*. Consolidation directly links protocols - to their implementations in a way that invoking a function from a + In order to speed up protocol dispatching, whenever all protocol implementations + are known up-front, typically after all Elixir code in a project is compiled, + Elixir provides a feature called *protocol consolidation*. Consolidation directly + links protocols to their implementations in a way that invoking a function from a consolidated protocol is equivalent to invoking two remote functions. - Protocol consolidation is applied by default to all Mix projects during - compilation. This may be an issue during test. For instance, if you want - to implement a protocol during test, the implementation will have no - effect, as the protocol has already been consolidated. One possible - solution is to include compilation directories that are specific to your - test environment in your mix.exs: + Protocol consolidation is applied by default to all Mix projects during compilation. + This may be an issue during test. For instance, if you want to implement a protocol + during test, the implementation will have no effect, as the protocol has already been + consolidated. One possible solution is to include compilation directories that are + specific to your test environment in your mix.exs: def project do ... @@ -439,7 +436,7 @@ defmodule Protocol do @spec extract_protocols([charlist | String.t()]) :: [atom] def extract_protocols(paths) do extract_matching_by_attribute(paths, 'Elixir.', fn module, attributes -> - case attributes[:protocol] do + case attributes[:__protocol__] do [fallback_to_any: _] -> module _ -> nil end @@ -470,7 +467,7 @@ defmodule Protocol do prefix = Atom.to_charlist(protocol) ++ '.' extract_matching_by_attribute(paths, prefix, fn _mod, attributes -> - case attributes[:protocol_impl] do + case attributes[:__impl__] do [protocol: ^protocol, for: for] -> for _ -> nil end @@ -561,7 +558,7 @@ defmodule Protocol do chunks = :lists.filter(fn {_name, value} -> value != :missing_chunk end, chunks) chunks = :lists.map(fn {name, value} -> {List.to_string(name), value} end, chunks) - case attributes[:protocol] do + case attributes[:__protocol__] do [fallback_to_any: any] -> {:ok, {any, definitions}, specs, {info, chunks}} @@ -795,8 +792,8 @@ defmodule Protocol do # Store information as an attribute so it # can be read without loading the module. - Module.register_attribute(__MODULE__, :protocol, persist: true) - @protocol [fallback_to_any: !!@fallback_to_any] + Module.register_attribute(__MODULE__, :__protocol__, persist: true) + @__protocol__ [fallback_to_any: !!@fallback_to_any] @doc false @spec __protocol__(:module) :: __MODULE__ @@ -855,8 +852,8 @@ defmodule Protocol do unquote(block) - Module.register_attribute(__MODULE__, :protocol_impl, persist: true) - @protocol_impl [protocol: @protocol, for: @for] + Module.register_attribute(__MODULE__, :__impl__, persist: true) + @__impl__ [protocol: @protocol, for: @for] unquote(impl) end @@ -897,8 +894,8 @@ defmodule Protocol do else quoted = quote do - Module.register_attribute(__MODULE__, :protocol_impl, persist: true) - @protocol_impl [protocol: unquote(protocol), for: unquote(for)] + Module.register_attribute(__MODULE__, :__impl__, persist: true) + @__impl__ [protocol: unquote(protocol), for: unquote(for)] @doc false @spec __impl__(:target) :: unquote(impl) |