Package {md4r}

Markdown parser flags

Description

The md4c library supports a number of markdown variants / options. The parsing of these is controlled by flags passed to the parser. The following functions provide commonly used utilities for these flags.

Usage

flags_available()

flags_describe()

flags_used(md)

Arguments

Value

flags_available() returns a character vector of available flags accepted by parse_md().

flags_describe() returns a tibble with columns flag and description describing each flag.

flags_used() returns a character vector of flags used in a parsed markdown document.

Examples

flags_available()

flags_describe()

md_file = system.file("examples/commonmark.md", package = "md4r")
md = parse_md(md_file)
flags_used(md)

Tools for creating block nodes

Description

These functions are used to create block nodes. Blocks nodes are used to represent block level elements in markdown.

Usage

md_block_doc(..., flags = "MD_DIALECT_COMMONMARK")

md_block_quote(...)

md_block_html(...)

md_block_p(...)

md_block_hr(...)

md_block_code(..., info = "", lang = "", fence_char = "`")

md_block_ul(..., tight = 1, mark = "*")

md_block_ol(..., tight = 1L, start = 1, mark_delimiter = ".")

md_block_li(..., is_task = 0, task_mark = " ")

md_block_h(..., level)

md_block_table(..., col_count, body_row_count, head_row_count = 1)

md_block_thead(...)

md_block_tbody(...)

md_block_tr(...)

md_block_th(..., align = c("default", "left", "center", "right"))

md_block_td(..., align = c("default", "left", "center", "right"))

Arguments

Value

Returns a list with a class of specified type along with md_span and md_node.

See Also

md_span, md_text

Tools for modifying md_node objects

Description

Overrides the $ operator so the content and attributes of md_node objects can be read and updated by name. Use node$content to access or replace the children of a block or span node (or the text of a text node), and ⁠node$<attr>⁠ to read or update an existing node attribute (e.g. level, href, mark).

Only attributes already present on the node may be replaced, and the new value is validated against the same rules used by the corresponding ⁠md_block_*⁠ / ⁠md_span_*⁠ constructor. The class and names attributes cannot be set this way.

Usage

## S3 method for class 'md_node'
x$name

## S3 replacement method for class 'md_node'
x$name <- value

## S3 replacement method for class 'md_text'
x$name <- value

Arguments

Value

A modified md_node object.

Examples

md = md_text_normal("Hello World")
md$content = "Nice to meet you"
md

md = md_block_ul(
  md_block_li(md_text_normal("bullet 1")),
  md_block_li(md_text_normal("bullet 2"))
)
md$mark = "-"
md$content[[1]]$content[[1]]$content = "first"
to_md(md) |> cat(sep = "\n")

Tools for creating span nodes

Description

These functions are used to create span nodes. Span nodes are used to represent inline elements in markdown and include things like links, images, code, emphasized text, strong text, and more.

Usage

md_span_em(...)

md_span_strong(...)

md_span_a(..., href, title)

md_span_img(..., src, title)

md_span_code(...)

md_span_del(...)

md_span_latexmath(...)

md_span_latexmath_display(...)

md_span_wikilink(..., target)

md_span_u(...)

Arguments

Value

Returns a list with a class of specified type along with md_span and md_node.

See Also

md_block, md_text

Tools for creating text nodes

Description

These functions are used to create text nodes. Text nodes are used to represent textual elements in markdown.

Usage

md_text_normal(x)

md_text_nullchar()

md_text_break()

md_text_softbreak()

md_text_entity(x)

md_text_code(x)

md_text_html(x)

md_text_latexmath(x)

Arguments

Value

Returns a character vector with a class of specified type along with md_text and md_node.

See Also

md_block, md_span

Parse markdown

Description

Parse either a literal markdown string or a markdown file given a path. Different dialects and features are supported via the flags argument. See flags_describe() for possible flags and their usage. parse_md() defaults parsing using the commonmark spec while parse_gfm() uses the GitHub flavored markdown spec.

Usage

parse_md(md, flags = "MD_DIALECT_COMMONMARK")

parse_gfm(md, flags = "MD_DIALECT_GITHUB")

Arguments

Value

Both functions return a markdown ast, a list with the md_block_doc class.

Examples

parse_md(system.file("examples/commonmark.md", package = "md4r"))

parse_gfm(system.file("examples/github.md", package = "md4r"))

Convert to html

Description

Coverts a markdown object (full ast or node) to HTML.

Usage

to_html(md, ...)

Arguments

Value

Returns a character vector of HTML lines representing the markdown object.

Examples

md_file = system.file("examples/commonmark.md", package = "md4r")
md = parse_md(md_file)
cat(to_html(md), sep="\n")

Convert to markdown

Description

Coverts a markdown object (full ast or node) to markdown text.

Usage

to_md(md, ...)

Arguments

Value

Returns a character vector of markdown lines representing the markdown object.

Examples

md_file = system.file("examples/commonmark.md", package = "md4r")
md = parse_md(md_file)
cat(to_md(md), sep="\n")