1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
|
-module(elixir_aliases).
-export([inspect/1, last/1, concat/1, safe_concat/1, format_error/1,
ensure_loaded/3, expand/2, expand_or_concat/2, store/5]).
-include("elixir.hrl").
inspect(Atom) when is_atom(Atom) ->
case elixir_config:is_bootstrap() of
true -> atom_to_binary(Atom);
false -> 'Elixir.Macro':inspect_atom(literal, Atom)
end.
%% Store an alias in the given scope
store(Meta, New, New, _TOpts, #{aliases := Aliases, macro_aliases := MacroAliases}) ->
{remove_alias(New, Aliases), remove_macro_alias(Meta, New, MacroAliases)};
store(Meta, New, Old, TOpts, #{aliases := Aliases, macro_aliases := MacroAliases} = E) ->
elixir_env:trace({alias, Meta, Old, New, TOpts}, E),
{store_alias(New, Old, Aliases), store_macro_alias(Meta, New, Old, MacroAliases)}.
store_alias(New, Old, Aliases) ->
lists:keystore(New, 1, Aliases, {New, Old}).
store_macro_alias(Meta, New, Old, Aliases) ->
case lists:keyfind(counter, 1, Meta) of
{counter, Counter} ->
lists:keystore(New, 1, Aliases, {New, {Counter, Old}});
false ->
Aliases
end.
remove_alias(Atom, Aliases) ->
lists:keydelete(Atom, 1, Aliases).
remove_macro_alias(Meta, Atom, Aliases) ->
case lists:keyfind(counter, 1, Meta) of
{counter, _Counter} ->
lists:keydelete(Atom, 1, Aliases);
false ->
Aliases
end.
%% Expand an alias. It returns an atom (meaning that there
%% was an expansion) or a list of atoms.
expand({'__aliases__', _Meta, ['Elixir' | _] = List}, _E) ->
concat(List);
expand({'__aliases__', Meta, _} = Alias, #{aliases := Aliases, macro_aliases := MacroAliases} = E) ->
case lists:keyfind(alias, 1, Meta) of
{alias, false} ->
expand(Alias, MacroAliases, E);
{alias, Atom} when is_atom(Atom) ->
Atom;
false ->
expand(Alias, Aliases, E)
end.
expand({'__aliases__', Meta, [H | T]}, Aliases, E) when is_atom(H) ->
Lookup = list_to_atom("Elixir." ++ atom_to_list(H)),
Counter = case lists:keyfind(counter, 1, Meta) of
{counter, C} -> C;
_ -> nil
end,
case lookup(Lookup, Aliases, Counter) of
Lookup -> [H | T];
Atom ->
elixir_env:trace({alias_expansion, Meta, Lookup, Atom}, E),
case T of
[] -> Atom;
_ -> concat([Atom | T])
end
end;
expand({'__aliases__', _Meta, List}, _Aliases, _E) ->
List.
%% Expands or concat if possible.
expand_or_concat(Aliases, E) ->
case expand(Aliases, E) of
[H | T] when is_atom(H) -> concat([H | T]);
AtomOrList -> AtomOrList
end.
%% Ensure a module is loaded before its usage.
%% Skip Kernel verification for bootstrap purposes.
ensure_loaded(_Meta, 'Elixir.Kernel', _E) ->
ok;
ensure_loaded(Meta, Module, #{module := Module} = E) ->
elixir_errors:file_error(Meta, E, ?MODULE, {circular_module, Module});
ensure_loaded(Meta, Module, E) ->
case code:ensure_loaded(Module) of
{module, Module} ->
ok;
_ ->
case wait_for_module(Module) of
found ->
ok;
Wait ->
Kind = case lists:member(Module, ?key(E, context_modules)) of
true -> scheduled_module;
false when Wait == deadlock -> deadlock_module;
false -> unloaded_module
end,
elixir_errors:file_error(Meta, E, ?MODULE, {Kind, Module})
end
end.
wait_for_module(Module) ->
case erlang:get(elixir_compiler_info) of
undefined -> not_found;
_ -> 'Elixir.Kernel.ErrorHandler':ensure_compiled(Module, module, hard)
end.
%% Receives an atom and returns the last bit as an alias.
last(Atom) ->
case atom_to_list(Atom) of
("Elixir." ++ [FirstLetter | _]) = List when FirstLetter >= $A, FirstLetter =< $Z ->
Last = last(lists:reverse(List), []),
{ok, list_to_atom("Elixir." ++ Last)};
_ ->
error
end.
last([$. | _], Acc) -> Acc;
last([H | T], Acc) -> last(T, [H | Acc]);
last([], Acc) -> Acc.
%% Receives a list of atoms, binaries or lists
%% representing modules and concatenates them.
concat(Args) -> binary_to_atom(do_concat(Args), utf8).
safe_concat(Args) -> binary_to_existing_atom(do_concat(Args), utf8).
do_concat([H | T]) when is_atom(H), H /= nil ->
do_concat([atom_to_binary(H) | T]);
do_concat([<<"Elixir.", _/binary>>=H | T]) ->
do_concat(T, H);
do_concat([<<"Elixir">>=H | T]) ->
do_concat(T, H);
do_concat(T) ->
do_concat(T, <<"Elixir">>).
do_concat([nil | T], Acc) ->
do_concat(T, Acc);
do_concat([H | T], Acc) when is_atom(H) ->
do_concat(T, <<Acc/binary, $., (to_partial(atom_to_binary(H)))/binary>>);
do_concat([H | T], Acc) when is_binary(H) ->
do_concat(T, <<Acc/binary, $., (to_partial(H))/binary>>);
do_concat([], Acc) ->
Acc.
to_partial(<<"Elixir.", Arg/binary>>) -> Arg;
to_partial(<<".", Arg/binary>>) -> Arg;
to_partial(Arg) when is_binary(Arg) -> Arg.
%% Lookup an alias in the current scope.
lookup(Else, Dict, Counter) ->
case lists:keyfind(Else, 1, Dict) of
{Else, {Counter, Value}} -> lookup(Value, Dict, Counter);
{Else, Value} when is_atom(Value) -> lookup(Value, Dict, Counter);
_ -> Else
end.
%% Errors
format_error({unloaded_module, Module}) ->
io_lib:format("module ~ts is not loaded and could not be found", [inspect(Module)]);
format_error({deadlock_module, Module}) ->
io_lib:format("module ~ts is not loaded and could not be found. "
"This may be happening because the module you are trying to load "
"directly or indirectly depends on the current module",
[inspect(Module)]);
format_error({scheduled_module, Module}) ->
io_lib:format(
"module ~ts is not loaded but was defined. This happens when you depend on "
"a module in the same context in which it is defined. For example:\n"
"\n"
" defmodule MyApp do\n"
" defmodule Mod do\n"
" end\n"
"\n"
" use Mod\n"
" end\n"
"\n"
"Try defining the module outside the context that uses it:\n"
"\n"
" defmodule MyApp.Mod do\n"
" end\n"
"\n"
" defmodule MyApp do\n"
" use MyApp.Mod\n"
" end\n"
"\n"
"If the module is defined at the top-level and you are trying to "
"use it at the top-level, this is not supported by Elixir",
[inspect(Module)]);
format_error({circular_module, Module}) ->
io_lib:format(
"you are trying to use/import/require the module ~ts which is currently being defined.\n"
"\n"
"This may happen if you accidentally override the module you want to use. For example:\n"
"\n"
" defmodule MyApp do\n"
" defmodule Supervisor do\n"
" use Supervisor\n"
" end\n"
" end\n"
"\n"
"In the example above, the new Supervisor conflicts with Elixir's Supervisor. "
"This may be fixed by using the fully qualified name in the definition:\n"
"\n"
" defmodule MyApp.Supervisor do\n"
" use Supervisor\n"
" end\n",
[inspect(Module)]).
|
