altparsers

The altparsers package allows the user or package developer to use alternative parsers for R code. It provides helpers for parsing and evaluating code and for starting a REPL with a non-standard R parser.

Ex is an example package which contains code to be used by the example parsers defined in the altparser package.

The expressions returned by the parsers are valid R expressions and are evaluated in the same way as normal R code.

library(altparsers)
repl(parser = tidy_parse_text)
#> [1, 2, 3] |> head(n = 1)

repl(parser = sexp_parse_text)
(= x 5)
(== x 5)
#> [1] TRUE
(+ x (* 3 5))
#> [1] 20

Within packages

tidyparsers::src() can be used within a package to source and evaluate code written for alternative parsers. Generally this code needs to be in a installed directory, such as inst/r2.

.onLoad <- function(libname, pkgname) {
  altparsers::src("r2", parser = altparsers::tidy_parse_file)
}