/
module.ex
2324 lines (1801 loc) · 72.7 KB
/
module.ex
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
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
defmodule Module do
@moduledoc ~S'''
Provides functions to deal with modules during compilation time.
It allows a developer to dynamically add, delete and register
attributes, attach documentation and so forth.
After a module is compiled, using many of the functions in
this module will raise errors, since it is out of their scope
to inspect runtime data. Most of the runtime data can be inspected
via the [`__info__/1`](`c:Module.__info__/1`) function attached to
each compiled module.
## Module attributes
Each module can be decorated with one or more attributes. The following ones
are currently defined by Elixir:
### `@after_compile`
A hook that will be invoked right after the current module is compiled.
Accepts a module or a `{module, function_name}`. See the "Compile callbacks"
section below.
### `@after_verify` (since v1.14.0)
A hook that will be invoked right after the current module is verified for
undefined functions, deprecations, etc. Accepts a module or a `{module, function_name}`.
See the "Compile callbacks" section below.
### `@before_compile`
A hook that will be invoked before the module is compiled.
Accepts a module or a `{module, function_or_macro_name}` tuple.
See the "Compile callbacks" section below.
### `@behaviour`
Note the British spelling!
Behaviours can be referenced by modules to ensure they implement
required specific function signatures defined by `@callback`.
For example, you could specify a `URI.Parser` behaviour as follows:
defmodule URI.Parser do
@doc "Defines a default port"
@callback default_port() :: integer
@doc "Parses the given URL"
@callback parse(uri_info :: URI.t()) :: URI.t()
end
And then a module may use it as:
defmodule URI.HTTP do
@behaviour URI.Parser
def default_port(), do: 80
def parse(info), do: info
end
If the behaviour changes or `URI.HTTP` does not implement
one of the callbacks, a warning will be raised.
For detailed documentation, see the
[behaviour typespec documentation](typespecs.md#behaviours).
### `@impl` (since v1.5.0)
To aid in the correct implementation of behaviours, you may optionally declare
`@impl` for implemented callbacks of a behaviour. This makes callbacks
explicit and can help you to catch errors in your code. The compiler will warn
in these cases:
* if you mark a function with `@impl` when that function is not a callback.
* if you don't mark a function with `@impl` when other functions are marked
with `@impl`. If you mark one function with `@impl`, you must mark all
other callbacks for that behaviour as `@impl`.
`@impl` works on a per-context basis. If you generate a function through a macro
and mark it with `@impl`, that won't affect the module where that function is
generated in.
`@impl` also helps with maintainability by making it clear to other developers
that the function is implementing a callback.
Using `@impl`, the example above can be rewritten as:
defmodule URI.HTTP do
@behaviour URI.Parser
@impl true
def default_port(), do: 80
@impl true
def parse(info), do: info
end
You may pass either `false`, `true`, or a specific behaviour to `@impl`.
defmodule Foo do
@behaviour Bar
@behaviour Baz
# Will warn if neither Bar nor Baz specify a callback named bar/0.
@impl true
def bar(), do: :ok
# Will warn if Baz does not specify a callback named baz/0.
@impl Baz
def baz(), do: :ok
end
The code is now more readable, as it is now clear which functions are
part of your API and which ones are callback implementations. To reinforce this
idea, `@impl true` automatically marks the function as `@doc false`, disabling
documentation unless `@doc` is explicitly set.
### `@compile`
Defines options for module compilation. This is used to configure
both Elixir and Erlang compilers, as any other compilation pass
added by external tools. For example:
defmodule MyModule do
@compile {:inline, my_fun: 1}
def my_fun(arg) do
to_string(arg)
end
end
Multiple uses of `@compile` will accumulate instead of overriding
previous ones. See the "Compile options" section below.
### `@deprecated` (since v1.6.0)
Provides the deprecation reason for a function. For example:
defmodule Keyword do
@deprecated "Use Kernel.length/1 instead"
def size(keyword) do
length(keyword)
end
end
The Mix compiler automatically looks for calls to deprecated modules
and emit warnings during compilation.
Using the `@deprecated` attribute will also be reflected in the
documentation of the given function and macro. You can choose between
the `@deprecated` attribute and the documentation metadata to provide
hard-deprecations (with warnings) and soft-deprecations (without warnings):
This is a soft-deprecation as it simply annotates the documentation
as deprecated:
@doc deprecated: "Use Kernel.length/1 instead"
def size(keyword)
This is a hard-deprecation as it emits warnings and annotates the
documentation as deprecated:
@deprecated "Use Kernel.length/1 instead"
def size(keyword)
Currently `@deprecated` only supports functions and macros. However
you can use the `:deprecated` key in the annotation metadata to
annotate the docs of modules, types and callbacks too.
We recommend using this feature with care, especially library authors.
Deprecating code always pushes the burden towards library users. We
also recommend for deprecated functionality to be maintained for long
periods of time, even after deprecation, giving developers plenty of
time to update (except for cases where keeping the deprecated API is
undesired, such as in the presence of security issues).
### `@doc` and `@typedoc`
Provides documentation for the entity that follows the attribute.
`@doc` is to be used with a function, macro, callback, or
macrocallback, while `@typedoc` with a type (public or opaque).
Accepts one of these:
* a string (often a heredoc)
* `false`, which will make the entity invisible to documentation-extraction
tools like [`ExDoc`](https://hexdocs.pm/ex_doc/)
* a keyword list, since Elixir 1.7.0
For example:
defmodule MyModule do
@typedoc "This type"
@typedoc since: "1.1.0"
@type t :: term
@doc "Hello world"
@doc since: "1.1.0"
def hello do
"world"
end
@doc """
Sums `a` to `b`.
"""
def sum(a, b) do
a + b
end
end
As can be seen in the example above, since Elixir 1.7.0 `@doc` and `@typedoc`
also accept a keyword list that serves as a way to provide arbitrary metadata
about the entity. Tools like [`ExDoc`](https://hexdocs.pm/ex_doc/) and
`IEx` may use this information to display annotations. A common use
case is the `:since` key, which may be used to annotate in which version the
function was introduced.
As illustrated in the example, it is possible to use these attributes
more than once before an entity. However, the compiler will warn if
used twice with binaries as that replaces the documentation text from
the preceding use. Multiple uses with keyword lists will merge the
lists into one.
Note that since the compiler also defines some additional metadata,
there are a few reserved keys that will be ignored and warned if used.
Currently these are: `:opaque` and `:defaults`.
Once this module is compiled, this information becomes available via
the `Code.fetch_docs/1` function.
### `@dialyzer`
Defines warnings to request or suppress when using `:dialyzer`.
Accepts an atom, a tuple, or a list of atoms and tuples. For example:
defmodule MyModule do
@dialyzer {:nowarn_function, [my_fun: 1]}
def my_fun(arg) do
M.not_a_function(arg)
end
end
For the list of supported warnings, see [`:dialyzer` module](`:dialyzer`).
Multiple uses of `@dialyzer` will accumulate instead of overriding
previous ones.
### `@external_resource`
Specifies an external resource for the current module.
Sometimes a module embeds information from an external file. This
attribute allows the module to annotate which external resources
have been used.
Tools may use this information to ensure the module is recompiled
in case any of the external resources change, see for example:
[`mix compile.elixir`](https://hexdocs.pm/mix/Mix.Tasks.Compile.Elixir.html).
The specified file path provided is interpreted as relative to
the folder containing the project's `mix.exs`, which is the
current working directory, not the file where `@external_resource`
is declared.
If the external resource does not exist, the module still has
a dependency on it, causing the module to be recompiled as soon
as the file is added.
### `@file`
Changes the filename used in stacktraces for the function or macro that
follows the attribute, such as:
defmodule MyModule do
@doc "Hello world"
@file "hello.ex"
def hello do
"world"
end
end
### `@moduledoc`
Provides documentation for the current module.
defmodule MyModule do
@moduledoc """
A very useful module.
"""
@moduledoc authors: ["Alice", "Bob"]
end
Accepts a string (often a heredoc) or `false` where `@moduledoc false`
will make the module invisible to documentation extraction tools like
[`ExDoc`](https://hexdocs.pm/ex_doc/).
Similarly to `@doc` also accepts a keyword list to provide metadata
about the module. For more details, see the documentation of `@doc`
above.
Once this module is compiled, this information becomes available via
the `Code.fetch_docs/1` function.
### `@on_definition`
A hook that will be invoked when each function or macro in the current
module is defined. Useful when annotating functions.
Accepts a module or a `{module, function_name}` tuple. The function
must take 6 arguments:
* the module environment
* the kind of the function/macro: `:def`, `:defp`, `:defmacro`, or `:defmacrop`
* the function/macro name
* the list of quoted arguments
* the list of quoted guards
* the quoted function body
If the function/macro being defined has multiple clauses, the hook will
be called for each clause.
Unlike other hooks, `@on_definition` will only invoke functions and
never macros. This is to avoid `@on_definition` callbacks from
redefining functions that have just been defined in favor of more
explicit approaches.
When just a module is provided, the function is assumed to be
`__on_definition__/6`.
#### Example
defmodule Hooks do
def on_def(_env, kind, name, args, guards, body) do
IO.puts("Defining #{kind} named #{name} with args:")
IO.inspect(args)
IO.puts("and guards")
IO.inspect(guards)
IO.puts("and body")
IO.puts(Macro.to_string(body))
end
end
defmodule MyModule do
@on_definition {Hooks, :on_def}
def hello(arg) when is_binary(arg) or is_list(arg) do
"Hello" <> to_string(arg)
end
def hello(_) do
:ok
end
end
### `@on_load`
A hook that will be invoked whenever the module is loaded.
Accepts the function name (as an atom) of a function in the current module.
The function must have an arity of 0 (no arguments). If the function does
not return `:ok`, the loading of the module will be aborted.
For example:
defmodule MyModule do
@on_load :load_check
def load_check do
if some_condition() do
:ok
else
:abort
end
end
def some_condition do
false
end
end
### `@vsn`
Specify the module version. Accepts any valid Elixir value, for example:
defmodule MyModule do
@vsn "1.0"
end
### Struct attributes
* `@derive` - derives an implementation for the given protocol for the
struct defined in the current module
* `@enforce_keys` - ensures the given keys are always set when building
the struct defined in the current module
See `defstruct/1` for more information on building and using structs.
### Typespec attributes
The following attributes are part of typespecs and are also built-in in
Elixir:
* `@type` - defines a type to be used in `@spec`
* `@typep` - defines a private type to be used in `@spec`
* `@opaque` - defines an opaque type to be used in `@spec`
* `@spec` - provides a specification for a function
* `@callback` - provides a specification for a behaviour callback
* `@macrocallback` - provides a specification for a macro behaviour callback
* `@optional_callbacks` - specifies which behaviour callbacks and macro
behaviour callbacks are optional
* `@impl` - declares an implementation of a callback function or macro
For detailed documentation, see the [typespec documentation](typespecs.md).
### Custom attributes
In addition to the built-in attributes outlined above, custom attributes may
also be added. Custom attributes are expressed using the `@/1` operator followed
by a valid variable name. The value given to the custom attribute must be a valid
Elixir value:
defmodule MyModule do
@custom_attr [some: "stuff"]
end
For more advanced options available when defining custom attributes, see
`register_attribute/3`.
## Compile callbacks
There are three compilation callbacks, invoked in this order:
`@before_compile`, `@after_compile`, and `@after_verify`.
They are described next.
### `@before_compile`
A hook that will be invoked before the module is compiled. This is
often used to change how the current module is being compiled.
Accepts a module or a `{module, function_or_macro_name}` tuple. The
function/macro must take one argument: the module environment. If
it's a macro, its returned value will be injected at the end of the
module definition before the compilation starts.
When just a module is provided, the function/macro is assumed to be
`__before_compile__/1`.
Callbacks will run in the order they are registered. Any overridable
definition will be made concrete before the first callback runs.
A definition may be made overridable again in another before compile
callback and it will be made concrete one last time after all callbacks
run.
*Note*: the callback function/macro must be placed in a separate module
(because when the callback is invoked, the current module does not yet exist).
#### Example
defmodule A do
defmacro __before_compile__(_env) do
quote do
def hello, do: "world"
end
end
end
defmodule B do
@before_compile A
end
B.hello()
#=> "world"
### `@after_compile`
A hook that will be invoked right after the current module is compiled.
Accepts a module or a `{module, function_name}` tuple. The function
must take two arguments: the module environment and its bytecode.
When just a module is provided, the function is assumed to be
`__after_compile__/2`.
Callbacks will run in the order they are registered.
`Module` functions expecting not yet compiled modules (such as `definitions_in/1`)
are still available at the time `@after_compile` is invoked.
#### Example
defmodule MyModule do
@after_compile __MODULE__
def __after_compile__(env, _bytecode) do
IO.inspect(env)
end
end
### `@after_verify`
A hook that will be invoked right after the current module is verified for
undefined functions, deprecations, etc. A module is always verified after
it is compiled. In Mix projects, a module is also verified when any of its
runtime dependencies change. Therefore this is useful to perform verification
of the current module while avoiding compile-time dependencies.
Accepts a module or a `{module, function_name}` tuple. The function
must take one argument: the module name. When just a module is provided,
the function is assumed to be `__after_verify__/1`.
Callbacks will run in the order they are registered.
`Module` functions expecting not yet compiled modules are no longer available
at the time `@after_verify` is invoked.
#### Example
defmodule MyModule do
@after_verify __MODULE__
def __after_verify__(module) do
IO.inspect(module)
:ok
end
end
## Compile options
The `@compile` attribute accepts different options that are used by both
Elixir and Erlang compilers. Some of the common use cases are documented
below:
* `@compile :debug_info` - includes `:debug_info` regardless of the
corresponding setting in `Code.get_compiler_option/1`
* `@compile {:debug_info, false}` - disables `:debug_info` regardless
of the corresponding setting in `Code.get_compiler_option/1`. Note
disabling `:debug_info` is not recommended as it removes the ability
of the Elixir compiler and other tools to static analyse the code.
If you want to remove the `:debug_info` while deploying, tools like
`mix release` already do such by default.
* `@compile {:inline, some_fun: 2, other_fun: 3}` - inlines the given
name/arity pairs. Inlining is applied locally, calls from another
module are not affected by this option
* `@compile {:autoload, false}` - disables automatic loading of
modules after compilation. Instead, the module will be loaded after
it is dispatched to
* `@compile {:no_warn_undefined, Mod}` or
`@compile {:no_warn_undefined, {Mod, fun, arity}}` - does not warn if
the given module or the given `Mod.fun/arity` are not defined
'''
@type definition :: {atom, arity}
@type def_kind :: :def | :defp | :defmacro | :defmacrop
@extra_error_msg_defines? "Use Kernel.function_exported?/3 and Kernel.macro_exported?/3 " <>
"to check for public functions and macros instead"
@extra_error_msg_definitions_in "Use the Module.__info__/1 callback to get public functions and macros instead"
@doc """
Provides runtime information about functions, macros, and other information
defined by the module.
Each module gets an `__info__/1` function when it's compiled. The function
takes one of the following items:
* `:attributes` - a keyword list with all persisted attributes
* `:compile` - a list with compiler metadata
* `:functions` - a keyword list of public functions and their arities
* `:macros` - a keyword list of public macros and their arities
* `:md5` - the MD5 of the module
* `:module` - the module atom name
* `:struct` - (since v1.14.0) if the module defines a struct and if so each field in order
"""
@callback __info__(:attributes) :: keyword()
@callback __info__(:compile) :: [term()]
@callback __info__(:functions) :: keyword()
@callback __info__(:macros) :: keyword()
@callback __info__(:md5) :: binary()
@callback __info__(:module) :: module()
@callback __info__(:struct) :: list(%{field: atom(), required: boolean()}) | nil
@doc """
Returns information about module attributes used by Elixir.
See the "Module attributes" section in the module documentation for more
information on each attribute.
## Examples
iex> map = Module.reserved_attributes()
iex> Map.has_key?(map, :moduledoc)
true
iex> Map.has_key?(map, :doc)
true
"""
@doc since: "1.12.0"
def reserved_attributes() do
%{
after_compile: %{
doc: "A hook that will be invoked right after the current module is compiled."
},
after_verify: %{
doc: "A hook that will be invoked right after the current module is verified."
},
before_compile: %{
doc: "A hook that will be invoked before the module is compiled."
},
behaviour: %{
doc: "Specifies that the current module implements a given behaviour."
},
enforce_keys: %{
doc:
"Ensures the given keys are always set when building the struct defined in the current module."
},
fallback_to_any: %{
doc:
"If set to `true` generates a default protocol implementation for all types (inside `defprotocol`)."
},
for: %{
doc:
"The current module/type a protocol implementation is being defined for (inside `defimpl`)."
},
protocol: %{
doc: "The current protocol being implemented (inside `defimpl`)."
},
on_definition: %{
doc:
"A hook that will be invoked when each function or macro in the current module is defined."
},
impl: %{
doc: "Declares an implementation of a callback function or macro."
},
compile: %{
doc: "Defines options for module compilation."
},
deprecated: %{
doc: "Provides the deprecation reason for a function."
},
moduledoc: %{
doc: "Provides documentation for the current module."
},
doc: %{
doc: "Provides documentation for a function/macro/callback."
},
typedoc: %{
doc: "Provides documentation for a type."
},
dialyzer: %{
doc: "Defines Dialyzer warnings to request or suppress."
},
external_resource: %{
doc: "Specifies an external resource for the current module."
},
file: %{
doc:
"Changes the filename used in stacktraces for the function or macro that follows the attribute."
},
on_load: %{
doc: "A hook that will be invoked whenever the module is loaded."
},
vsn: %{
doc: "Specify the module version."
},
type: %{
doc: "Defines a type to be used in `@spec`."
},
typep: %{
doc: "Defines a private type to be used in `@spec`."
},
opaque: %{
doc: "Defines an opaque type to be used in `@spec`."
},
spec: %{
doc: "Provides a specification for a function."
},
callback: %{
doc: "Provides a specification for a behaviour callback."
},
macrocallback: %{
doc: "Provides a specification for a macro behaviour callback."
},
optional_callbacks: %{
doc: "Specifies which behaviour callbacks and macro behaviour callbacks are optional."
},
derive: %{
doc:
"Derives an implementation for the given protocol for the struct defined in the current module."
}
}
end
@doc """
Checks if a module is open.
A module is "open" if it is currently being defined and its attributes and
functions can be modified.
"""
@spec open?(module) :: boolean
def open?(module) when is_atom(module) do
:elixir_module.is_open(module)
end
@doc """
Evaluates the quoted contents in the given module's context.
A list of environment options can also be given as argument.
See `Code.eval_string/3` for more information.
Raises an error if the module was already compiled.
## Examples
defmodule Foo do
contents =
quote do
def sum(a, b), do: a + b
end
Module.eval_quoted(__MODULE__, contents)
end
Foo.sum(1, 2)
#=> 3
For convenience, you can pass any `Macro.Env` struct, such
as `__ENV__/0`, as the first argument or as options. Both
the module and all options will be automatically extracted
from the environment:
defmodule Foo do
contents =
quote do
def sum(a, b), do: a + b
end
Module.eval_quoted(__ENV__, contents)
end
Foo.sum(1, 2)
#=> 3
Note that if you pass a `Macro.Env` struct as first argument
while also passing `opts`, they will be merged with `opts`
having precedence.
"""
@spec eval_quoted(module | Macro.Env.t(), Macro.t(), list, keyword | Macro.Env.t()) :: term
def eval_quoted(module_or_env, quoted, binding \\ [], opts \\ [])
def eval_quoted(%Macro.Env{} = env, quoted, binding, opts)
when is_list(binding) and is_list(opts) do
validated_eval_quoted(env.module, quoted, binding, struct!(env, opts))
end
def eval_quoted(module, quoted, binding, %Macro.Env{} = env)
when is_atom(module) and is_list(binding) do
validated_eval_quoted(module, quoted, binding, env)
end
def eval_quoted(module, quoted, binding, opts)
when is_atom(module) and is_list(binding) and is_list(opts) do
validated_eval_quoted(module, quoted, binding, opts)
end
defp validated_eval_quoted(module, quoted, binding, env_or_opts) do
assert_not_compiled!({:eval_quoted, 4}, module)
:elixir_def.reset_last(module)
env = :elixir.env_for_eval(env_or_opts)
{value, binding, _env} = :elixir.eval_quoted(quoted, binding, %{env | module: module})
{value, binding}
end
@doc """
Creates a module with the given name and defined by
the given quoted expressions.
The line where the module is defined and its file **must**
be passed as options.
It returns a tuple of shape `{:module, module, binary, term}`
where `module` is the module name, `binary` is the module
bytecode and `term` is the result of the last expression in
`quoted`.
Similar to `Kernel.defmodule/2`, the binary will only be
written to disk as a `.beam` file if `Module.create/3` is
invoked in a file that is currently being compiled.
## Examples
contents =
quote do
def world, do: true
end
Module.create(Hello, contents, Macro.Env.location(__ENV__))
Hello.world()
#=> true
## Differences from `defmodule`
`Module.create/3` works similarly to `Kernel.defmodule/2`
and return the same results. While one could also use
`Kernel.defmodule/2` to define modules dynamically, this function
is preferred when the module body is given by a quoted
expression.
Another important distinction is that `Module.create/3`
allows you to control the environment variables used
when defining the module, while `Kernel.defmodule/2`
automatically uses the environment it is invoked at.
"""
@spec create(module, Macro.t(), Macro.Env.t() | keyword) :: {:module, module, binary, term}
def create(module, quoted, opts)
def create(module, quoted, %Macro.Env{} = env) when is_atom(module) do
create([line: env.line], module, quoted, env)
end
def create(module, quoted, opts) when is_atom(module) and is_list(opts) do
unless Keyword.has_key?(opts, :file) do
raise ArgumentError, "expected :file to be given as option"
end
meta = Keyword.take(opts, [:line, :generated])
create(meta, module, quoted, :elixir.env_for_eval(opts))
end
defp create(meta, module, quoted, env_or_opts) do
next = :elixir_module.next_counter(nil)
quoted = :elixir_quote.linify_with_context_counter(meta, {module, next}, quoted)
:elixir_module.compile(module, quoted, [], false, :elixir.env_for_eval(env_or_opts))
end
@doc """
Concatenates a list of aliases and returns a new alias.
It handles binaries and atoms.
## Examples
iex> Module.concat([Foo, Bar])
Foo.Bar
iex> Module.concat([Foo, "Bar"])
Foo.Bar
"""
@spec concat([binary | atom]) :: atom
def concat(list) when is_list(list) do
:elixir_aliases.concat(list)
end
@doc """
Concatenates two aliases and returns a new alias.
It handles binaries and atoms.
## Examples
iex> Module.concat(Foo, Bar)
Foo.Bar
iex> Module.concat(Foo, "Bar")
Foo.Bar
"""
@spec concat(binary | atom, binary | atom) :: atom
def concat(left, right)
when (is_binary(left) or is_atom(left)) and (is_binary(right) or is_atom(right)) do
:elixir_aliases.concat([left, right])
end
@doc """
Concatenates a list of aliases and returns a new alias only if the alias
was already referenced.
If the alias was not referenced yet, fails with `ArgumentError`.
It handles binaries and atoms.
## Examples
iex> Module.safe_concat([List, Chars])
List.Chars
"""
@spec safe_concat([binary | atom]) :: atom
def safe_concat(list) when is_list(list) do
:elixir_aliases.safe_concat(list)
end
@doc """
Concatenates two aliases and returns a new alias only if the alias was
already referenced.
If the alias was not referenced yet, fails with `ArgumentError`.
It handles binaries and atoms.
## Examples
iex> Module.safe_concat(List, Chars)
List.Chars
"""
@spec safe_concat(binary | atom, binary | atom) :: atom
def safe_concat(left, right)
when (is_binary(left) or is_atom(left)) and (is_binary(right) or is_atom(right)) do
:elixir_aliases.safe_concat([left, right])
end
# Build signatures to be stored in docs
defp build_signature(args, env) do
{reverse_args, counters} = simplify_args(args, %{}, [], env)
expand_keys(reverse_args, counters, [])
end
defp simplify_args([arg | args], counters, acc, env) do
{arg, counters} = simplify_arg(arg, counters, env)
simplify_args(args, counters, [arg | acc], env)
end
defp simplify_args([], counters, reverse_args, _env) do
{reverse_args, counters}
end
defp simplify_arg({:\\, _, [left, right]}, counters, env) do
{left, counters} = simplify_arg(left, counters, env)
right =
Macro.prewalk(right, fn
{:@, _, _} = attr -> Macro.expand_once(attr, env)
other -> other
end)
{{:\\, [], [left, right]}, counters}
end
# If the variable is being used explicitly for naming,
# we always give it a higher priority (nil) even if it
# starts with underscore.
defp simplify_arg({:=, _, [{var, _, atom}, _]}, counters, _env) when is_atom(atom) do
{simplify_var(var, nil), counters}
end
defp simplify_arg({:=, _, [_, {var, _, atom}]}, counters, _env) when is_atom(atom) do
{simplify_var(var, nil), counters}
end
# If we have only the variable as argument, it also gets
# higher priority. However, if the variable starts with an
# underscore, we give it a secondary context (Elixir) with
# lower priority.
defp simplify_arg({var, _, atom}, counters, _env) when is_atom(atom) do
{simplify_var(var, Elixir), counters}
end
defp simplify_arg({:%, _, [left, _]}, counters, env) do
case Macro.expand_once(left, env) do
module when is_atom(module) -> autogenerated_key(counters, simplify_module_name(module))
_ -> autogenerated_key(counters, :struct)
end
end
defp simplify_arg({:%{}, _, _}, counters, _env) do
autogenerated_key(counters, :map)
end
defp simplify_arg({:@, _, _} = attr, counters, env) do
simplify_arg(Macro.expand_once(attr, env), counters, env)
end
defp simplify_arg({:var!, _, [{var, _, atom} | _]}, counters, _env) when is_atom(atom) do
{simplify_var(var, Elixir), counters}
end
defp simplify_arg(other, counters, _env) when is_integer(other),
do: autogenerated_key(counters, :int)
defp simplify_arg(other, counters, _env) when is_boolean(other),
do: autogenerated_key(counters, :bool)
defp simplify_arg(other, counters, _env) when is_atom(other),