call_modify: Modify the arguments of a call

Description

Modify the arguments of a call

Usage

call_modify(.call, ..., .standardise = FALSE, .env = caller_env())

Arguments

.call

Can be a call, a formula quoting a call in the right-hand side, or a frame object from which to extract the call expression.

...

Named or unnamed expressions (constants, names or calls) used to modify the call. Use NULL to remove arguments. These dots support tidy dots features.

.standardise

If TRUE, the call is standardised beforehand to match existing unnamed arguments to their argument names. This prevents new named arguments from accidentally replacing original unnamed arguments.

.env

The environment where to find the call definition in case call is not wrapped in a quosure. This is passed to call_standardise() if .standardise is TRUE.

Value

A quosure if .call is a quosure, a call otherwise.

Life cycle

In rlang 0.2.0, lang_modify() was soft-deprecated and renamed to call_modify(). See lifecycle section in call2() for more about this change.

Examples

Run this code

# NOT RUN {
call <- quote(mean(x, na.rm = TRUE))

# Modify an existing argument
call_modify(call, na.rm = FALSE)
call_modify(call, x = quote(y))

# Remove an argument
call_modify(call, na.rm = NULL)

# Add a new argument
call_modify(call, trim = 0.1)

# Add an explicit missing argument
call_modify(call, na.rm = quote(expr = ))

# Supply a list of new arguments with `!!!`
newargs <- list(na.rm = NULL, trim = 0.1)
call_modify(call, !!! newargs)

# Supply a call frame to extract the frame expression:
f <- function(bool = TRUE) {
  call_modify(call_frame(), splice(list(bool = FALSE)))
}
f()


# You can also modify quosures inplace:
f <- quo(matrix(bar))
call_modify(f, quote(foo))
# }