Package 'parsermd'

Stuff

Description

Stuff

Author(s)

Colin Rundel [email protected]

---

Convert an object into an rmd_ast.

Description

Currently only supports conversion of rmd_tibble objects back to rmd_ast.

Usage

as_ast(x, ...)

Arguments

x	Object to convert
...	Unused, for extensibility.

Value

Returns an rmd_ast object.

Examples

parse_rmd(system.file("hw01.Rmd", package="parsermd")) %>%
  as_tibble() %>%
  as_ast()

---

Convert an rmd_ast, rmd_tibble, or any ast node into text.

Description

Convert an rmd_ast, rmd_tibble, or any ast node into text.

Usage

as_document(x, padding = "", collapse = NULL, ...)

Arguments

x	rmd_ast, rmd_tibble, or parsermd node object.
padding	Padding to add between nodes when assembling the text.
collapse	If not NULL, use value to collapse lines.
...	Unused, for extensibility.

Value

Returns a character vector.

---

Get and set code chunk options

Description

Helper functions for obtaining or changing chunk options within an rmd object.

Usage

rmd_set_options(x, ...)

rmd_get_options(x, ..., defaults = list())

Arguments

x	An rmd_ast, rmd_tibble, or any rmd ast node object.
...	Either a collection of named values for the setter or a character values of the option names for the getter.
defaults	A named list of default values for the options.

Value

rmd_set_options returns the modified version of the original object.

rmd_get_options returns a list of the requested options (or all options if none are specified). Non-chunk nodes return NULL.

Examples

rmd = parse_rmd(system.file("minimal.Rmd", package = "parsermd"))

str(rmd_get_options(rmd))
str(rmd_get_options(rmd), "include")

rmd_set_options(rmd, include = TRUE)

---

Parse an R Markdown document

Description

Documents are parse into an rmd_ast object.

Usage

parse_rmd(rmd, allow_incomplete = FALSE, parse_yaml = TRUE)

Arguments

rmd	Either the path to an Rmd file or a character vector containing the contents of a R Markdown document.
allow_incomplete	Allow incomplete parsing of the document.
parse_yaml	Use the yaml package to parse the document's yaml.

Value

Returns a rmd_ast object.

Examples

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

---

Render parsermd objects using rmarkdown::render()

Description

Object contents are converted to a character vector and written to a temporary directory before rendering.

Note that this function has the potential to overwrite existing output files (e.g. .html, .pdf, etc).

Usage

render(x, name = NULL, ...)

Arguments

x	Object to render, e.g. a rmd_ast, rmd_tibble, character vector, etc.
name	Name of the output file, if not given it will be inferred from the name of x.
...	Any additional arguments to be passed to rmarkdown::render()

Value

Returns the results of rmarkdown::render().

---

Check an Rmd against a template

Description

This function compares the provided Rmd against a template and reports on discrepancies (e.g. missing or unmodified components).

Usage

rmd_check_template(rmd, template, ...)

Arguments

rmd	The rmd to be check, can be an rmd_ast, rmd_tibble, or text that can be handled by parse_rmd.
template	rmd_template object from rmd_template().
...	Unused, for extensibility.

Value

Invisibly returns TRUE if the rmd matches the template, FALSE otherwise.

Examples

tmpl = parse_rmd(system.file("hw01.Rmd", package = "parsermd")) %>%
  rmd_select(by_section(c("Exercise *", "Solution"))) %>%
  rmd_template(keep_content = TRUE)

rmd_check_template(
  system.file("hw01-student.Rmd", package = "parsermd"),
  tmpl
)

---

rmd node utility functions

Description

Functions for extracting information for Rmd nodes.

Usage

rmd_node_label(x, ...)

rmd_node_type(x, ...)

rmd_node_length(x, ...)

rmd_node_content(x, ...)

rmd_node_attr(x, attr, ...)

rmd_node_engine(x, ...)

rmd_node_options(x, ...)

rmd_node_code(x, ...)

Arguments

x	An rmd object, e.g. rmd_ast or rmd_tibble.
...	Unused, for extensibility.
attr	Attribute name to extract.

Value

• rmd_node_label() - returns a character vector of node labels, nodes without labels return NA.

• rmd_node_type() - returns a character vector of node types.

• rmd_node_length() - returns an integer vector of node lengths (i.e. lines of code, lines of text, etc.), nodes without a length return NA.

• rmd_node_content() - returns a character vector of node textual content, nodes without content return NA.

• rmd_node_attr() - returns a list of node attribute values.

• rmd_node_engine() - returns a character vector of chunk engines, NA for all other node types.

• rmd_node_options() - returns a list of chunk node options (named list), MULL for all other node types.

• rmd_node_code() - returns a list of chunk node code (character vector), NULL for all other node types.

Examples

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

rmd_node_label(rmd)
rmd_node_type(rmd)
rmd_node_content(rmd)
rmd_node_attr(rmd, "level")
rmd_node_engine(rmd)
rmd_node_options(rmd)
rmd_node_code(rmd)

---

Find the sections for each rmd object node

Description

Uses the section headings of an rmd object to identify the hierarchical structure of the document.

Usage

rmd_node_sections(x, levels = 1:6, drop_na = FALSE)

Arguments

x	An rmd object, e.g. rmd_ast or rmd_tibble.
levels	Limit which section heading levels to return.
drop_na	Should NA sections be dropped.

Value

A list of section names for each node.

---

Select nodes of an Rmd ast

Description

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 additional parsermd specific selection helpers are available: by_section(), has_type(), has_label(), and has_option().

Usage

rmd_select(x, ...)

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.

Value

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

Examples

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

rmd_select(rmd, "plot-dino", "cor-dino")
rmd_select(rmd, "plot-dino":"cor-dino")
rmd_select(rmd, `plot-dino`:`cor-dino`)

rmd_select(rmd, has_type("rmd_chunk"))

rmd_select(rmd, by_section(c("Exercise *", "Solution")))

---

Rmd selection helper functions

Description

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_option() - selects nodes that have the given option(s) set.

Usage

has_type(types)

by_section(sec_ref, keep_parents = TRUE)

has_label(label)

has_option(...)

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.
...	Either option names represented by a scalar string or a named argument with the form opt = value where opt is the option name and value is the value to be checked. For example eval = TRUE would check for the option eval being set to TRUE.

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.

Value

All helper functions return an integer vector of selected indexes.

Examples

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

rmd_select(rmd, has_type("rmd_chunk"))

rmd_select(rmd, has_label("*dino"))

rmd_select(rmd, has_option("message"))
rmd_select(rmd, has_option(message = FALSE))
rmd_select(rmd, has_option(message = TRUE))

---

Source the code chunks of an Rmd document

Description

This is the equivalent of the source() function for Rmd files or their resulting asts.

Usage

rmd_source(x, local = FALSE, ..., label_comment = TRUE, use_eval = TRUE)

Arguments

x	An Rmd document (e.g. rmd_ast, rmd_tibble, Rmd file path, etc.)
local	TRUE, FALSE or an environment, determining where the parsed expressions are evaluated. FALSE (the default) corresponds to the user's workspace (the global environment) and TRUE to the environment from which source is called.
...	Additional arguments passed to source.
label_comment	Attach chunk labels as comment before each code block.
use_eval	Use the eval chunk option to determine if code is included.

Value

Returns the result of source() for any R code chunks.

Examples

rmd_source(system.file("minimal.Rmd", package = "parsermd"), echo=TRUE)

---

Subset the nodes of an rmd object

Description

Subset an rmd object based on sections, node types, or names.

Usage

rmd_subset(
  x,
  sec_refs = NULL,
  type_refs = NULL,
  name_refs = NULL,
  exclude = FALSE,
  keep_yaml = TRUE,
  keep_setup = FALSE,
  ...
)

Arguments

x	rmd object, e.g. rmd_ast or rmd_tibble.
sec_refs	Section references, TODO - add details.
type_refs	Node type references, TODO - add details.
name_refs	Name references, TODO - add details.
exclude	Should the matching nodes be excluded.
keep_yaml	Should the document yaml be kept.
keep_setup	Should the document setup chunk be kept.
...	Unused, for extensibility.

Value

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

---

rmd_subset utility functions

Description

Tools for selecting or checking a single node using rmd_subset() selection.

Usage

rmd_get_node(x, sec_refs = NULL, type_refs = NULL, name_refs = NULL, ...)

rmd_get_chunk(x, sec_refs = NULL, name_refs = NULL)

rmd_get_markdown(x, sec_refs = NULL)

rmd_has_node(x, sec_refs = NULL, type_refs = NULL, name_refs = NULL, ...)

rmd_has_chunk(x, sec_refs = NULL, name_refs = NULL, ...)

rmd_has_markdown(x, sec_refs = NULL, ...)

Arguments

x	rmd object, e.g. rmd_ast or rmd_tibble.
sec_refs	Section references, TODO - add details.
type_refs	Node type references, TODO - add details.
name_refs	Name references, TODO - add details.
...	Unused, for extensibility.

Value

• ⁠rmd_get_*()⁠ functions returns a single Rmd node object (e.g. rmd_heading, rmd_chunk, rmd_markdown, etc.)

• ⁠rmd_has_*()⁠ functions return TRUE if a matching node exists, FALSE otherwise.

---

Create a template from an rmd object.

Description

Templates are objects which are meant to capture the structure of an R Markdown document and facilitate the comparison between the template and new Rmd documents, usually to ensure the structure and/or content matches sufficiently.

Usage

rmd_template(
  rmd,
  keep_content = FALSE,
  keep_labels = TRUE,
  keep_headings = FALSE,
  keep_yaml = FALSE,
  ...
)

Arguments

rmd	R Markdown document in the form of an rmd_ast or rmd_tibble.
keep_content	Should the template keep the document's content (markdown text and chunk code).
keep_labels	Should the template keep the document's code chunk labels.
keep_headings	Should the template keep the document's headings.
keep_yaml	Should the template keep the document's yaml.
...	Unused, for extensibility.

Value

Returns an rmd_template object, which is a derived tibble containing relevant structural details of the document.

Examples

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

rmd_select(rmd, by_section(c("Exercise *", "Solution"))) %>%
  rmd_template()

---