R: Examples for 'rlang::quosure-tools'

### ** Examples

quo <- quo(my_quosure)
quo

<quosure>
expr: ^my_quosure
env:  0x55ccfe0931b8

# Access and set the components of a quosure:
quo_get_expr(quo)

my_quosure

quo_get_env(quo)

<environment: 0x55ccfe0931b8>

quo <- quo_set_expr(quo, quote(baz))
quo <- quo_set_env(quo, empty_env())
quo

<quosure>
expr: ^baz
env:  empty

# Test wether an object is a quosure:
is_quosure(quo)

[1] TRUE

# If it is a quosure, you can use the specialised type predicates
# to check what is inside it:
quo_is_symbol(quo)

[1] TRUE

quo_is_call(quo)

[1] FALSE

quo_is_null(quo)

[1] FALSE

# quo_is_missing() checks for a special kind of quosure, the one
# that contains the missing argument:
quo()

<quosure>
expr: ^
env:  empty

quo_is_missing(quo())

[1] TRUE

fn <- function(arg) enquo(arg)
fn()

<quosure>
expr: ^
env:  empty

quo_is_missing(fn())

[1] TRUE

Examples for 'rlang::quosure-tools'