These functions are used in conjunction with rmd_select() to
select nodes from an Rmd ast.
by_section()- uses section selectors to select nodes.has_type()- selects all nodes that have the given type(s).has_label()- selects nodes with labels matching the given glob.has_heading()- selects heading nodes (only) with titles matching the given glob pattern(s).has_option()- selects nodes that have the given option(s) set.has_shortcode()- selects nodes containing shortcodes matching the given function name(s).by_fdiv()- selects fenced div sections where all provided patterns match the div attributes.
Usage
has_type(types)
by_section(sec_ref, keep_parents = TRUE)
has_label(label)
has_heading(heading)
has_code(code)
has_option(...)
has_shortcode(func_name = NULL)
has_inline_code(engine = NULL)
by_fdiv(..., regexp = FALSE)Arguments
- types
Vector of character type names, e.g.
rmd_chunk,rmd_heading, etc.- sec_ref
character vector, a section reference selector. See details below for further details on how these are constructed.
- keep_parents
Logical, retain the parent headings of selected sections. Default:
TRUE- label
character vector, glob patterns for matching chunk labels.
- heading
character vector, glob patterns for matching heading titles.
- code
character vector, regex patterns for matching chunk code line(s)
- ...
Character vector patterns to match against fenced div attributes. All provided patterns must match at least one attribute in the div's attr property.
- func_name
character vector, optional glob patterns for matching shortcode function names. If NULL (default), matches any shortcode.
- engine
character vector, optional glob patterns for matching inline code engine names. If NULL (default), matches any inline code.
- regexp
Logical, use regular expressions for pattern matching instead of glob patterns. Default: FALSE (uses glob patterns).
Details
Section reference selectors
Section reference selectors are a simplified version of CSS selectors that are designed to enable the selection nodes in a way that respects the implied hierarchy of a document's section headings.
They consist of a character vector of heading names where each subsequent value
is assumed to be nested within the preceding value. For example, the section
selector c("Sec 1", "Sec 2") would select all nodes that are contained within
a section named Sec 2 that is in turn contained within a section named Sec 1
(or a section contained within a section named Sec 1, and so on).
The individual section names can be specified using wildcards (aka globbing
patterns), which may match one or more sections within the document, e.g.
c("Sec 1", "Sec *"). See utils::glob2rx() or
wikipedia
for more details on the syntax for these patterns.
See also
rmd_select() for the main selection function that uses these helpers.
Examples
rmd = parse_rmd(system.file("examples/hw01.Rmd", package="parsermd"))
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, has_label("*dino"))
#> ├── YAML [2 fields]
#> ├── Chunk [r, 5 lines] - plot-dino
#> └── Chunk [r, 2 lines] - cor-dino
rmd_select(rmd, has_heading("Exercise *"))
#> ├── YAML [2 fields]
#> ├── Heading [h3] - Exercise 1
#> ├── Heading [h3] - Exercise 2
#> └── Heading [h3] - Exercise 3
rmd_select(rmd, has_option("message"))
#> ├── YAML [2 fields]
#> └── Chunk [r, 2 lines] - load-packages
rmd_select(rmd, has_option(message = FALSE))
#> └── YAML [2 fields]
rmd_select(rmd, has_option(message = TRUE))
#> └── YAML [2 fields]
rmd_select(rmd, has_shortcode())
#> └── YAML [2 fields]
rmd_select(rmd, has_shortcode("video"))
#> └── YAML [2 fields]
rmd_select(rmd, by_fdiv("note"))
#> └── YAML [2 fields]
rmd_select(rmd, by_fdiv(".warning", "important"))
#> └── YAML [2 fields]