201 lines
6.0 KiB
Erlang
201 lines
6.0 KiB
Erlang
-module(elixir_aliases).
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-export([inspect/1, last/1, concat/1, safe_concat/1, format_error/1,
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ensure_loaded/3, expand/4, store/7]).
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-include("elixir.hrl").
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inspect(Atom) when is_atom(Atom) ->
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case elixir_config:get(bootstrap) of
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true -> atom_to_binary(Atom, utf8);
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false -> 'Elixir.Code.Identifier':inspect_as_atom(Atom)
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end.
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%% Store an alias in the given scope
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store(Meta, New, New, _TOpts, Aliases, MacroAliases, _Lexical) ->
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{remove_alias(New, Aliases), remove_macro_alias(Meta, New, MacroAliases)};
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store(Meta, New, Old, TOpts, Aliases, MacroAliases, Lexical) ->
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record_warn(Meta, New, TOpts, Lexical),
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{store_alias(New, Old, Aliases),
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store_macro_alias(Meta, New, Old, MacroAliases)}.
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store_alias(New, Old, Aliases) ->
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lists:keystore(New, 1, Aliases, {New, Old}).
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store_macro_alias(Meta, New, Old, Aliases) ->
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case lists:keyfind(counter, 1, Meta) of
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{counter, Counter} ->
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lists:keystore(New, 1, Aliases, {New, {Counter, Old}});
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false ->
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Aliases
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end.
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remove_alias(Atom, Aliases) ->
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lists:keydelete(Atom, 1, Aliases).
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remove_macro_alias(Meta, Atom, Aliases) ->
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case lists:keyfind(counter, 1, Meta) of
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{counter, _Counter} ->
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lists:keydelete(Atom, 1, Aliases);
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false ->
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Aliases
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end.
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record_warn(Meta, Ref, Opts, Lexical) ->
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Warn =
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case lists:keyfind(warn, 1, Opts) of
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{warn, false} -> false;
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{warn, true} -> true;
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false -> not lists:keymember(context, 1, Meta)
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end,
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elixir_lexical:record_alias(Ref, ?line(Meta), Warn, Lexical).
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%% Expand an alias. It returns an atom (meaning that there
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%% was an expansion) or a list of atoms.
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expand({'__aliases__', _Meta, ['Elixir' | _] = List}, _Aliases, _MacroAliases, _LexicalTracker) ->
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concat(List);
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expand({'__aliases__', Meta, _} = Alias, Aliases, MacroAliases, LexicalTracker) ->
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case lists:keyfind(alias, 1, Meta) of
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{alias, false} ->
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expand(Alias, MacroAliases, LexicalTracker);
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{alias, Atom} when is_atom(Atom) ->
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Atom;
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false ->
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expand(Alias, Aliases, LexicalTracker)
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end.
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expand({'__aliases__', Meta, [H | T]}, Aliases, LexicalTracker) when is_atom(H) ->
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Lookup = list_to_atom("Elixir." ++ atom_to_list(H)),
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Counter = case lists:keyfind(counter, 1, Meta) of
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{counter, C} -> C;
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_ -> nil
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end,
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case lookup(Lookup, Aliases, Counter) of
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Lookup -> [H | T];
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Atom ->
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elixir_lexical:record_alias(Lookup, LexicalTracker),
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case T of
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[] -> Atom;
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_ -> concat([Atom | T])
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end
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end;
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expand({'__aliases__', _Meta, List}, _Aliases, _LexicalTracker) ->
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List.
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%% Ensure a module is loaded before its usage.
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ensure_loaded(_Meta, 'Elixir.Kernel', _E) -> ok;
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ensure_loaded(Meta, Ref, E) ->
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try
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Ref:module_info(module)
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catch
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error:undef ->
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Kind = case lists:member(Ref, ?key(E, context_modules)) of
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true ->
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case ?key(E, module) of
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Ref -> circular_module;
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_ -> scheduled_module
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end;
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false -> unloaded_module
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end,
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elixir_errors:form_error(Meta, ?key(E, file), ?MODULE, {Kind, Ref})
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end.
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%% Receives an atom and returns the last bit as an alias.
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last(Atom) ->
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Last = last(lists:reverse(atom_to_list(Atom)), []),
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list_to_atom("Elixir." ++ Last).
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last([$. | _], Acc) -> Acc;
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last([H | T], Acc) -> last(T, [H | Acc]);
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last([], Acc) -> Acc.
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%% Receives a list of atoms, binaries or lists
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%% representing modules and concatenates them.
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concat(Args) -> binary_to_atom(do_concat(Args), utf8).
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safe_concat(Args) -> binary_to_existing_atom(do_concat(Args), utf8).
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do_concat([H | T]) when is_atom(H), H /= nil ->
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do_concat([atom_to_binary(H, utf8) | T]);
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do_concat([<<"Elixir.", _/binary>>=H | T]) ->
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do_concat(T, H);
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do_concat([<<"Elixir">>=H | T]) ->
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do_concat(T, H);
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do_concat(T) ->
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do_concat(T, <<"Elixir">>).
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do_concat([nil | T], Acc) ->
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do_concat(T, Acc);
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do_concat([H | T], Acc) when is_atom(H) ->
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do_concat(T, <<Acc/binary, $., (to_partial(atom_to_binary(H, utf8)))/binary>>);
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do_concat([H | T], Acc) when is_binary(H) ->
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do_concat(T, <<Acc/binary, $., (to_partial(H))/binary>>);
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do_concat([], Acc) ->
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Acc.
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to_partial(<<"Elixir.", Arg/binary>>) -> Arg;
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to_partial(<<".", Arg/binary>>) -> Arg;
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to_partial(Arg) when is_binary(Arg) -> Arg.
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%% Lookup an alias in the current scope.
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lookup(Else, Dict, Counter) ->
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case lists:keyfind(Else, 1, Dict) of
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{Else, {Counter, Value}} -> lookup(Value, Dict, Counter);
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{Else, Value} when is_atom(Value) -> lookup(Value, Dict, Counter);
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_ -> Else
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end.
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%% Errors
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format_error({unloaded_module, Module}) ->
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io_lib:format("module ~ts is not loaded and could not be found", [inspect(Module)]);
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format_error({scheduled_module, Module}) ->
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io_lib:format(
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"module ~ts is not loaded but was defined. This happens when you depend on "
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"a module in the same context in which it is defined. For example:\n"
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"\n"
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" defmodule MyApp do\n"
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" defmodule Mod do\n"
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" end\n"
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"\n"
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" use Mod\n"
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" end\n"
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"\n"
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"Try defining the module outside the context that uses it:\n"
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"\n"
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" defmodule MyApp.Mod do\n"
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" end\n"
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"\n"
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" defmodule MyApp do\n"
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" use MyApp.Mod\n"
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" end\n"
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"\n"
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"If the module is defined at the top-level and you are trying to "
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"use it at the top-level, this is not supported by Elixir",
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[inspect(Module)]);
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format_error({circular_module, Module}) ->
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io_lib:format(
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"you are trying to use the module ~ts which is currently being defined.\n"
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"\n"
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"This may happen if you accidentally override the module you want to use. For example:\n"
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"\n"
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" defmodule MyApp do\n"
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" defmodule Supervisor do\n"
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" use Supervisor\n"
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" end\n"
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" end\n"
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"\n"
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"In the example above, the new Supervisor conflicts with Elixir's Supervisor. "
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"This may be fixed by using the fully qualified name in the definition:\n"
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"\n"
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" defmodule MyApp.Supervisor do\n"
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" use Supervisor\n"
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" end\n",
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[inspect(Module)]).
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