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#' Constructive options for type 'language'
#'
#' These options will be used on objects of type 'language'. By default this
#' function is useless as nothing can be set, this is provided in case users want
#' to extend the method with other constructors.
#'
#' Depending on `constructor`, we construct the object as follows:
#' * `"default"` : We use constructive's deparsing algorithm on attributeless calls,
#' and use `as.call()` on other language elements when attributes need to be constructed.
#'
#' @param constructor String. Name of the function used to construct the object.
#' @inheritParams opts_atomic
#'
#' @return An object of class <constructive_options/constructive_options_language>
#' @export
opts_language <- function(constructor = c("default"), ...) {
.cstr_options("language", constructor = constructor[[1]], ...)
}
#' @export
#' @method .cstr_construct language
.cstr_construct.language <- function(x, ...) {
opts <- list(...)$opts$language %||% opts_language()
if (is_corrupted_language(x)) return(NextMethod())
UseMethod(".cstr_construct.language", structure(NA, class = opts$constructor))
}
is_corrupted_language <- function(x) {
!typeof(x) %in% c("language", "symbol", "expression")
}
#' @export
#' @method .cstr_construct.language default
.cstr_construct.language.default <- function(x, ...) {
if (identical(x, quote(expr=))) return("quote(expr = )")
x_stripped <- x
attributes(x_stripped) <- NULL
if (is_expression2(x_stripped)) {
code <- deparse_call0(x_stripped, ...)
code <- .cstr_wrap(code, "quote", new_line = FALSE)
} else {
list_call <- .cstr_apply(as.list(x_stripped), "list", ...)
code <- .cstr_wrap(list_call, "as.call", new_line = FALSE)
}
repair_attributes_language(x, code, ...)
}
repair_attributes_language <- function(x, code, ...) {
.cstr_repair_attributes(
x, code, ...,
ignore = c("srcref", "srcfile", "wholeSrcref")
)
}
is_expression2 <- function(x) {
non_srcref_attr_nms <- setdiff(
names(attributes(x)),
c("srcref", "srcfile", "wholeSrcref")
)
if (length(non_srcref_attr_nms)) return(FALSE)
if (rlang::is_syntactic_literal(x) || rlang::is_symbol(x)) return(TRUE)
if (!rlang::is_call(x)) return(FALSE)
if (is_regular_function_definition(x)) return(TRUE)
all(vapply(x, is_expression2, logical(1)))
}
is_regular_function_definition <- function(x) {
identical(x[[1]], as.symbol("function")) &&
length(x) == 4 &&
(
is.null(x[[2]]) ||
(is.pairlist(x[[2]]) && all(vapply(x[[2]], is_expression2, logical(1))))
) &&
is_expression2(x[[3]])
}
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