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:
module
- the current module name file
- the current file name as a binary line
- the current line as an integer function
- a tuple as {atom, integer}
, where the first element is the function name and the second its arity; returns nil
if not inside a function context
- the context of the environment; it can be nil
(default context), inside a guard or inside a match aliases
- a list of two-element tuples, where the first element is the aliased name and the second one the actual name requires
- the list of required modules functions
- a list of functions imported from each module macros
- a list of macros imported from each module macro_aliases
- a list of aliases defined inside the current macro context_modules
- a list of modules defined in the current context lexical_tracker
- PID of the lexical tracker which is responsible for keeping user info The following fields pertain to variable handling and must not be accessed or relied on. To get a list of all variables, see vars/1
:
current_vars
unused_vars
prematch_vars
contextual_vars
The following fields are deprecated and must not be accessed or relied on:
vars
- a list keeping all defined variables as {var, context}
Checks if a variable belongs to the environment
Returns whether the compilation environment is currently inside a guard
Returns whether the compilation environment is currently inside a match clause
Returns a keyword list containing the file and line information as keys
Returns the environment stacktrace
Returns a Macro.Env
in the match context
Returns a list of variables in the current environment
aliases() :: [{module(), module()}]
context() :: :match | :guard | nil
context_modules() :: [module()]
file() :: binary()
functions() :: [{module(), [name_arity()]}]
lexical_tracker() :: pid() | nil
line() :: non_neg_integer()
macro_aliases() :: [{module(), {integer(), module()}}]
macros() :: [{module(), [name_arity()]}]
name_arity() :: {atom(), arity()}
requires() :: [module()]
t() :: %Macro.Env{ module: atom(), file: file(), line: line(), function: name_arity() | nil, context: context(), requires: requires(), aliases: aliases(), functions: functions(), macros: macros(), macro_aliases: aliases(), context_modules: context_modules(), vars: vars(), unused_vars: unused_vars(), current_vars: current_vars(), prematch_vars: prematch_vars(), lexical_tracker: lexical_tracker(), contextual_vars: contextual_vars() }
var() :: {atom(), atom() | non_neg_integer()}
has_var?(t(), var()) :: boolean()
Checks if a variable belongs to the environment.
in_guard?(t()) :: boolean()
Returns whether the compilation environment is currently inside a guard.
in_match?(t()) :: boolean()
Returns whether the compilation environment is currently inside a match clause.
location(t()) :: keyword()
Returns a keyword list containing the file and line information as keys.
stacktrace(t()) :: list()
Returns the environment stacktrace.
to_match(t()) :: t()
Returns a Macro.Env
in the match context.
vars(t()) :: [var()]
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/1.7.3/Macro.Env.html