Read, write, and edit QMD files — read

Usage

read_qmd(path, ast = c("pd", "ts"), ...)

write_qmd(x, path)

edit_qmd(path, .f, ...)

Arguments

path: Path to a .qmd file.
ast: Which AST to build, "pd" (Pandoc, default) or "ts" (tree-sitter); passed to parse_qmd().
...: Further arguments passed to parse_qmd().
x: A pandoc or ts_tree object to render.
.f: A function (or rlang formula) taking the parsed AST and returning the edited AST.

Value

read_qmd() returns a pandoc or ts_tree; write_qmd() and edit_qmd() return the (edited) AST invisibly.

Details

Thin file-oriented conveniences around parse_qmd() and to_qmd() that close the parse-edit-write loop (parsermd's as_document() role):

read_qmd() parses a file path (and, unlike parse_qmd(), errors if the path does not exist rather than treating it as inline text).
write_qmd() renders an AST with to_qmd() and writes it verbatim, with no added trailing newline so the round trip stays byte-faithful. Returns its input invisibly so it can end a pipe.
edit_qmd() is the in-place one-liner: read, apply .f, write back.

Examples

path = tempfile(fileext = ".qmd")
writeLines("# Title\n\nSome text.\n", path)

read_qmd(path)
#> pandoc
#> ├─header level=1 (#title)
#> │ └─str "Title"
#> └─paragraph
#>   ├─str "Some"
#>   ├─space
#>   └─str "text."

edit_qmd(path, \(d) map_nodes(d, is(pandoc_header),
                              .f = \(h) add_class(h, "done")))
cat(readLines(path), sep = "\n")
#> # Title {.done}
#> 
#> Some text.