Select nodes of an Rmd ast

This function is implemented using tidyselect::eval_select() which enables a variety of useful syntax for selecting nodes from the ast.

Additionally, a number of parsermd helpers are available: by_section(), has_type(), has_label(), and has_option().

Usage

rmd_select(x, ..., keep_yaml = TRUE)

Arguments

x

Rmd object, e.g. rmd_ast or rmd_tibble.

...

One or more unquoted expressions separated by commas. Chunk labels can be used as if they were positions in the data frame, so expressions like x:y can be used to select a range of nodes.

keep_yaml

Logical, whether to automatically include YAML nodes in the selection. If TRUE (default), equivalent to including has_type("rmd_yaml") in the selection.

Value

Returns a subset Rmd object (either rmd_ast or rmd_tibble depending on input).

See also

rmd_select_helpers for helper functions to use with rmd_select(), including by_section(), has_type(), has_label(), and has_option().

Examples

rmd = parse_rmd(system.file("examples/hw01.Rmd", package = "parsermd"))

rmd_select(rmd, "plot-dino", "cor-dino")
#> ├── YAML [2 fields]
#> ├── Chunk [r, 5 lines] - plot-dino
#> └── Chunk [r, 2 lines] - cor-dino
rmd_select(rmd, "plot-dino":"cor-dino")
#> ├── YAML [2 fields]
#> ├── Chunk [r, 5 lines] - plot-dino
#> ├── Markdown [1 line]
#> └── Chunk [r, 2 lines] - cor-dino
rmd_select(rmd, `plot-dino`:`cor-dino`)
#> ├── YAML [2 fields]
#> ├── Chunk [r, 5 lines] - plot-dino
#> ├── Markdown [1 line]
#> └── Chunk [r, 2 lines] - cor-dino

rmd_select(rmd, has_type("rmd_chunk"))
#> ├── YAML [2 fields]
#> ├── Chunk [r, 2 lines] - load-packages
#> ├── Chunk [r, 5 lines] - plot-dino
#> ├── Chunk [r, 2 lines] - cor-dino
#> ├── Chunk [r, 1 line] - plot-star
#> └── Chunk [r, 1 line] - cor-star

rmd_select(rmd, by_section(c("Exercise *", "Solution")))
#> ├── YAML [2 fields]
#> ├── Heading [h3] - Exercise 1
#> │   └── Heading [h4] - Solution
#> │       └── Markdown [1 line]
#> ├── Heading [h3] - Exercise 2
#> │   └── Heading [h4] - Solution
#> │       ├── Markdown [3 lines]
#> │       ├── Chunk [r, 5 lines] - plot-dino
#> │       ├── Markdown [1 line]
#> │       └── Chunk [r, 2 lines] - cor-dino
#> └── Heading [h3] - Exercise 3
#>     └── Heading [h4] - Solution
#>         ├── Markdown [3 lines]
#>         ├── Chunk [r, 1 line] - plot-star
#>         ├── Markdown [1 line]
#>         └── Chunk [r, 1 line] - cor-star