env_cache {rlang}

R Documentation

Cache a value in an environment

Description

env_cache() is a wrapper around env_get() and env_poke() designed to retrieve a cached value from env.

• If the nm binding exists, it returns its value.

• Otherwise, it stores the default value in env and returns that.

Usage

env_cache(env, nm, default)

Arguments

env	An environment.
nm	Name of binding, a string.
default	The default value to store in env if nm does not exist yet.

Value

Either the value of nm or default if it did not exist yet.

Examples

Run examples

e <- env(a = "foo")

# Returns existing binding
env_cache(e, "a", "default")

# Creates a `b` binding and returns its default value
env_cache(e, "b", "default")

# Now `b` is defined
e$b

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