Struggling with `{{` links

[lionel-]

I'd like to hyperlink mentions of the {{ operator in the rlang doc because it is not easily searchable.

Here is a counter example with !! that works well:

gen <- function(body) {
  header <- "
#' Foo
#' @md
#' @name foo
#' @description
#'"
  text <- paste0(c(header, body, "NULL"), collapse = "\n")
  roxygen2::roc_proc_text(roxygen2::rd_roclet(), text)
}

gen("#' [`!!`][op-inject]")
#> $foo.Rd
#> % Generated by roxygen2: do not edit by hand
#> % Please edit documentation in ./<text>
#> \name{foo}
#> \alias{foo}
#> \title{Foo}
#> \description{
#> \code{\link[=op-inject]{!!}}
#> }

I would like to generate a similar link for {{, properly escaped:

#> \code{\link[=op-inject]{\{\{}}

Ideally [`{{`][foo] would work but here is what we get:

gen("#' [`{{`][op-embrace]")
#> Warning: [<text>:5] @description mismatched braces or quotes
#> $foo.Rd
#> % Generated by roxygen2: do not edit by hand
#> % Please edit documentation in ./<text>
#> \name{foo}
#> \alias{foo}
#> \title{Foo}
#> \description{
#>
#> }

Escaping { does not work (same result with \\\\{\\\\}):

gen("#' [`\\{\\{`][op-embrace]")
#> Warning: [<text>:5] @description mismatched braces or quotes
#> $foo.Rd
#> % Generated by roxygen2: do not edit by hand
#> % Please edit documentation in ./<text>
#> \name{foo}
#> \alias{foo}
#> \title{Foo}
#> \description{
#>
#> }

And unfortunately, trying to insert Rd manually does not work either

gen("#' \\code{\\link[=foo]{\\{\\{}}}}")
#> Warning: [<text>:5] @description mismatched braces or quotes
#> $foo.Rd
#> % Generated by roxygen2: do not edit by hand
#> % Please edit documentation in ./<text>
#> \name{foo}
#> \alias{foo}
#> \title{Foo}
#> \description{
#>
#> }

gen("#' \\code{\\link[=foo]{\\\\{\\\\{}}}}")
#> $foo.Rd
#> % Generated by roxygen2: do not edit by hand
#> % Please edit documentation in ./<text>
#> \name{foo}
#> \alias{foo}
#> \title{Foo}
#> \description{
#> \code{\link[=foo]{\\{\\{}}}}
#> }

Fixing [`{{`][foo] so that it works as expected would be great. But I'd appreciate pointers to a workaround as well.

[gaborcsardi]

IDK if there is a way to write it with markdown, but this seems to work:

#' This is a link \code{\link[=foo]{\{\{}}

[gaborcsardi]

You can define a function for it as well:

braces <- function() "\\code{\\link[=foo]{\\{\\{}}"

#' Foo
#' @md
#' @name foo
#' @description
#' This is a link `r braces()`.

[lionel-]

Thanks, it seems the Rd works properly with the dev version but not the CRAN one.

[gaborcsardi]

Thanks, it seems the Rd works properly with the dev version but not the CRAN one.

IDK, but there seems to be no difference between CRAN and dev roxygen2 at this point, and the one with the braces() function definitely works with CRAN roxygen2 for me.

[lionel-]

Both the Rd and the md reprexes are fixed with the dev version actually. But not with CRAN roxygen. Very weird.

[lionel-]

Sorry that's my bad, I forgot to reset this changelist:

modified   R/markdown.R
@@ -193,7 +193,7 @@ mdxml_node_to_rd <- function(xml, state) {
     unknown = mdxml_children_to_rd(xml, state),
 
     paragraph = paste0("\n\n", mdxml_children_to_rd(xml, state)),
-    text = escape_comment(xml_text(xml)),
+    text = escape_verb(xml_text(xml)),
     emph = paste0("\\emph{", mdxml_children_to_rd(xml, state), "}"),
     strong = paste0("\\strong{", mdxml_children_to_rd(xml, state), "}"),
     softbreak = mdxml_break(state),

This explains the differences I was observing.