#' RegExplain Addin
#'
#' Addin for regexplain. If the selection does not contain multiple lines, the
#' addin tries to evaluate the selection and coerce the result to a character
#' string. Only unique lines are passed to the gadget to maximize screen space.
#' The max number of lines returned is set by the option
#' `regexplain.addin.max_lines`, with a default value of 100 lines.
#' If evaluating the selection does not produce a character vector without
#' errors, the original selection is returned.
#'
#' @keywords internal
regexplain_addin <- function() {
# Get the document context.
context <- rstudioapi::getActiveDocumentContext()
# Get context text
ctx_text <- context$selection[[1]]$text
max_lines <- getOption("rexeplain.addin.max_lines", 100)
# If it is one line and evaluates to something, use that
# Otherwise treat as text
obj <- tryCatch(
{
if (grepl("\n", ctx_text)) {
ctx_text[1:min(length(ctx_text), max_lines)]
} else {
x <- eval(parse(text = ctx_text))
if (inherits(x, "list")) x <- unlist(x)
x <- as.character(x)
if (length(x) == 1 && grepl("\n", x)) {
x <- strsplit(x, "\n")[[1]]
}
x <- unique(x)
if (length(x) > max_lines) {
message(
ctx_text,
" gave ",
length(x),
" lines, limiting to first ",
max_lines,
" unique lines. Set ",
"options('regexplain.addin.max_lines') to a higher value to ",
"increase the number of lines."
)
x <- unique(x)
x[1:min(length(x), max_lines)]
} else {
x
}
}
},
error = function(e) {
as.character(ctx_text[1:min(length(ctx_text), max_lines)])
}
)
regexplain_gadget(if (length(obj) && obj != "") obj)
}
#' @describeIn regexplain_gadget Opens file chooser to pick file, reads lines,
#' returns first `regexplain.addin.max_lines` (default 100). Used in the
#' "Regexplain File" [regexplain_addin].
#' @export
regexplain_file <- function(pattern = NULL, start_page = "RegEx") {
fname <- file.choose()
x <- readLines(fname)
max_lines <- getOption("rexeplain.addin.max_lines", 100)
if (length(x) > max_lines) {
message("There were ", format(length(x), big.mark = ","), " lines in ",
fname, "\nUsing only first ", max_lines, ".\n",
"Set options('regexplain.addin.max_lines') to a higher value to ",
"increase the number of lines.")
x <- x[1:max_lines]
}
regexplain_gadget(text = x, pattern = pattern, start_page = start_page)
}
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