node_replace() gives the replacement for a particular node.
node_replace_all() does the same but for several nodes (e.g. the output of
node_find_all()). The output of those functions can be passed to
tree_rewrite() to rewrite the entire input code with those replacements.
Arguments
- x
A node, either from
tree_root()or from anothernode_*()function.- ...
Named elements where the name is a rule ID and the value is a character string indicating the replacement to apply to nodes that match this rule. Meta-variables are accepted but the syntax is different: they must be wrapped in
~~, e.g"anyNA(~~VAR~~)".
Examples
src <- "
x <- c(1, 2, 3)
any(duplicated(x), na.rm = TRUE)
any(duplicated(x))
if (any(is.na(x))) {
TRUE
}
any(is.na(y))"
root <- tree_new(src) |>
tree_root()
### Only replace the first nodes found by each rule
nodes_to_replace <- root |>
node_find(
ast_rule(id = "any_na", pattern = "any(is.na($VAR))"),
ast_rule(id = "any_dup", pattern = "any(duplicated($VAR))")
)
nodes_to_replace |>
node_replace(
any_na = "anyNA(~~VAR~~)",
any_dup = "anyDuplicated(~~VAR~~) > 0"
)
#> [[1]]
#> [[1]][[1]]
#> [1] 73
#>
#> [[1]][[2]]
#> [1] 86
#>
#> [[1]][[3]]
#> [1] "anyNA(x)"
#>
#>
#> [[2]]
#> [[2]][[1]]
#> [1] 50
#>
#> [[2]][[2]]
#> [1] 68
#>
#> [[2]][[3]]
#> [1] "anyDuplicated(x) > 0"
#>
#>
#> attr(,"class")
#> [1] "astgrep_replacement" "list"
### Replace all nodes found by each rule
nodes_to_replace <- root |>
node_find(
ast_rule(id = "any_na", pattern = "any(is.na($VAR))"),
ast_rule(id = "any_dup", pattern = "any(duplicated($VAR))")
)
nodes_to_replace |>
node_replace(
any_na = "anyNA(~~VAR~~)",
any_dup = "anyDuplicated(~~VAR~~) > 0"
)
#> [[1]]
#> [[1]][[1]]
#> [1] 73
#>
#> [[1]][[2]]
#> [1] 86
#>
#> [[1]][[3]]
#> [1] "anyNA(x)"
#>
#>
#> [[2]]
#> [[2]][[1]]
#> [1] 50
#>
#> [[2]][[2]]
#> [1] 68
#>
#> [[2]][[3]]
#> [1] "anyDuplicated(x) > 0"
#>
#>
#> attr(,"class")
#> [1] "astgrep_replacement" "list"