Macro.Env
A struct that holds compile time environment information.
The current environment can be accessed at any time as __ENV__/0
. Inside macros, the caller environment can be accessed as __CALLER__/0
.
An instance of Macro.Env
must not be modified by hand. If you need to create a custom environment to pass to Code.eval_quoted/3
, use the following trick:
def make_custom_env do import SomeModule, only: [some_function: 2] alias A.B.C __ENV__ end
You may then call make_custom_env()
to get a struct with the desired imports and aliases included.
It contains the following fields:
-
aliases
- a list of two-element tuples, where the first element is the aliased name and the second one the actual name -
context
- the context of the environment; it can benil
(default context),:guard
(inside a guard) or:match
(inside a match) -
context_modules
- a list of modules defined in the current context -
file
- the current file name as a binary -
function
- a tuple as{atom, integer}
, where the first element is the function name and the second its arity; returnsnil
if not inside a function -
functions
- a list of functions imported from each module -
line
- the current line as an integer -
macro_aliases
- a list of aliases defined inside the current macro -
macros
- a list of macros imported from each module -
module
- the current module name -
requires
- the list of required modules
The following fields are private to Elixir's macro expansion mechanism and must not be accessed directly:
contextual_vars
current_vars
lexical_tracker
prematch_vars
tracers
unused_vars
The following fields are deprecated and must not be accessed or relied on:
-
vars
- a list keeping all defined variables as{var, context}
Summary
Types
Functions
- has_var?(env, var)
Checks if a variable belongs to the environment.
- in_guard?(env)
Returns whether the compilation environment is currently inside a guard.
- in_match?(env)
Returns whether the compilation environment is currently inside a match clause.
- location(env)
Returns a keyword list containing the file and line information as keys.
- stacktrace(env)
Returns the environment stacktrace.
- to_match(env)
Returns a
Macro.Env
in the match context.- vars(env)
Returns a list of variables in the current environment.
Types
aliases()Source
Specs
aliases() :: [{module(), module()}]
context()Source
Specs
context() :: :match | :guard | nil
context_modules()Source
Specs
context_modules() :: [module()]
file()Source
Specs
file() :: binary()
functions()Source
Specs
functions() :: [{module(), [name_arity()]}]
lexical_tracker()Source
Specs
lexical_tracker() :: pid() | nil
line()Source
Specs
line() :: non_neg_integer()
macro_aliases()Source
Specs
macro_aliases() :: [{module(), {term(), module()}}]
macros()Source
Specs
macros() :: [{module(), [name_arity()]}]
name_arity()Source
Specs
name_arity() :: {atom(), arity()}
requires()Source
Specs
requires() :: [module()]
t()Source
Specs
t() :: %Macro.Env{ aliases: aliases(), context: context(), context_modules: context_modules(), contextual_vars: contextual_vars(), current_vars: current_vars(), file: file(), function: name_arity() | nil, functions: functions(), lexical_tracker: lexical_tracker(), line: line(), macro_aliases: macro_aliases(), macros: macros(), module: module(), prematch_vars: prematch_vars(), unused_vars: unused_vars(), requires: requires(), tracers: tracers(), vars: vars() }
variable()Source
Specs
variable() :: {atom(), atom() | term()}
Functions
has_var?(env, var)Source
Specs
has_var?(t(), variable()) :: boolean()
Checks if a variable belongs to the environment.
in_guard?(env)Source
Specs
in_guard?(t()) :: boolean()
Returns whether the compilation environment is currently inside a guard.
in_match?(env)Source
Specs
in_match?(t()) :: boolean()
Returns whether the compilation environment is currently inside a match clause.
location(env)Source
Specs
location(t()) :: keyword()
Returns a keyword list containing the file and line information as keys.
stacktrace(env)Source
Specs
stacktrace(t()) :: list()
Returns the environment stacktrace.
to_match(env)Source
Specs
to_match(t()) :: t()
Returns a Macro.Env
in the match context.
vars(env)Source
Specs
vars(t()) :: [variable()]
Returns a list of variables in the current environment.
Each variable is identified by a tuple of two elements, where the first element is the variable name as an atom and the second element is its context, which may be an atom or an integer.
© 2012 Plataformatec
Licensed under the Apache License, Version 2.0.
https://hexdocs.pm/elixir/1.12.0/Macro.Env.html