These helpers are useful to make your function work generically with quosures and raw expressions. First call get_expr() to extract an expression. Once you're done processing the expression, call set_expr() on the original object to update the expression. You can return the result of set_expr(), either a formula or an expression depending on the input type. Note that set_expr() does not change its input, it creates a new object.

set_expr(x, value)

get_expr(x, default = x)

Arguments

x

An expression or one-sided formula. In addition, set_expr() accept frames.

value

An updated expression.

default

A default expression to return when x is not an expression wrapper. Defaults to x itself.

Value

The updated original input for set_expr(). A raw expression for get_expr().

Examples

f <- ~foo(bar) e <- quote(foo(bar)) frame <- identity(identity(ctxt_frame())) get_expr(f)
#> foo(bar)
get_expr(e)
#> foo(bar)
get_expr(frame)
#> identity(ctxt_frame())
set_expr(f, quote(baz))
#> ~baz #> <environment: 0x7f97a425acb0>
set_expr(e, quote(baz))
#> baz