Make Function Arguments Explicit

Transform function calls in R source code so that all arguments are passed with explicit parameter names. Uses a recursive tree-walking approach: every function call node is inspected, the called function's formals are retrieved, and positional arguments are given their formal parameter name.

Transformation preserves all content outside the expression boundaries (roxygen docs, section comments, blank lines). Inline comments on the last line of a transformed expression are re-attached to the output.

If the function has a ... formal, unmatched positional and named arguments are left in place as-is (they are captured by ...).

Operators (+, -, *, /, etc.), subset operators ([, [[, $), assignment (<-, =, <<-), and special syntax (if, for, while, repeat, {, (, function) are not transformed.

Usage

package_func_arg_explicit(path = NULL, skip_functions = NULL, ...)

make_func_arg_explicit(path = NULL, skip_functions = NULL, ...)

Arguments

path

Path to an R file to modify. If NULL and RStudio is available, the active document path is used.

skip_functions

Optional character vector of function or operator names to skip during transformation (e.g. c("my_special_fn")). In addition to user-provided names, all built-in operators (+, -, etc.), special syntax forms (if, for, {, etc.), and all %...% infix operators (%in%, %>%, %||%, etc.) are always skipped automatically.

...

Additional arguments. Currently unused and must be empty.

Value

Invisible NULL, called for its side effect of writing the transformed code back to the file.

Functions

• package_func_arg_explicit(): Processes all .R files in a package's R/ directory, making function arguments explicit.

Single-file operation

Operates on one R file. When path is NULL and RStudio is available, the currently active document is used automatically.

Examples

# \donttest{
tf <- tempfile(fileext = ".R")
writeLines("vapply(1:9, function(x) x*2, numeric(1))", tf)
make_func_arg_explicit(tf)
#> ✔ Made function arguments explicit in /tmp/RtmpAM3FIu/file1b244e6da79a.R
cat(readLines(tf), sep = "\n")
#> vapply(X = 1:9, FUN = function(x) x * 2, FUN.VALUE = numeric(length = 1))
# vapply(X = 1:9, FUN = function(x) x*2, FUN.VALUE = numeric(1))
# }