Generate Mutants for a Single R File — mutate

Creates mutants for a single R source file by combining AST-based mutations from the C++ mutation engine with fallback line-deletion mutants.

Usage

mutate_file(
  src_file,
  out_dir = "mutations",
  max_mutants = NULL,
  max_line_deletions = 5
)

Arguments

src_file: Path to an R source file.
out_dir: Directory where mutant files are written.
max_mutants: Optional cap on the number of returned mutants. If set, a random subset of generated mutants is returned.
max_line_deletions: Maximum number of line-deletion mutants generated per file (a random subset of deletable lines). These complement the AST-based statement deletions by also covering top-level / non-block lines. Use 0 to disable line-deletion mutants entirely. Defaults to 5.

Value

A list of mutants. Each element contains:

path: Path to the mutant file.
info: Formatted mutation metadata (file, source range, and details).

Examples

src <- tempfile(fileext = ".R")
writeLines("add <- function(x, y) x + y", src)
mutants <- mutate_file(src, out_dir = tempfile("mutations_"), max_mutants = 1)
#> Generated 1 AST-based mutants for file19fb53a983a9.R
length(mutants)
#> [1] 1