env_poke() will assign or reassign a binding in env if create
is TRUE. If create is FALSE and a binding does not already
exists, an error is issued.
Usage
env_poke(env = caller_env(), nm, value, inherit = FALSE, create = !inherit)Arguments
- env
An environment.
- nm
Name of binding, a string.
- value
The value for a new binding.
- inherit
Whether to look for bindings in the parent environments.
- create
Whether to create a binding if it does not already exist in the environment.
Value
The old value of nm or a zap sentinel if the
binding did not exist yet.
Details
If inherit is TRUE, the parents environments are checked for
an existing binding to reassign. If not found and create is
TRUE, a new binding is created in env. The default value for
create is a function of inherit: FALSE when inheriting,
TRUE otherwise.
This default makes sense because the inheriting case is mostly
for overriding an existing binding. If not found, something
probably went wrong and it is safer to issue an error. Note that
this is different to the base R operator <<- which will create
a binding in the global environment instead of the current
environment when no existing binding is found in the parents.
See also
env_bind() for binding multiple elements. env_cache()
for a variant of env_poke() designed to cache values.