Package 'pandocfilters'

Block Objects

Description

In pandoc "block" objects are used as container for "inline" objects and to give them specific roles. Objects of the classes "NULL" and "character" can be coerced to "block".

Usage

as.block(x)

Arguments

x	an object of type "NULL" or "character" or "block".

Value

an object of class "block".

Examples

as.block("some text")
as.block(NULL)

---

Inline Objects

Description

Objects of the classes "NULL" and "character" can be coerced to "inline".

Usage

as.inline(x)

Arguments

x	an object of type "NULL", "character" or "inline".

Value

an object of class "inline".

Examples

as.inline("some text")
as.inline(NULL)

---

Apply a Function on a AST

Description

Apply the function FUN on the abstract syntax tree (AST) obtained from pandoc.

Usage

astrapply(x, FUN, ...)

Arguments

x	a list representing the AST obtained from pandoc.
FUN	the function to be applied to the AST.
...	optional arguments to FUN.

Value

A list containing the modified AST.

---

Attributes

Description

A constructor for pandoc attributes.

Usage

Attr(identifier = "", classes = character(), key_val_pairs = list())

Arguments

identifier	a character string
classes	a character giving the classes
key_val_pairs	a list of tuple of type "character"

Examples

Attr("A", c("B", "C"), list(c("D", "E")))

---

Block Quote

Description

Constructs a block object of type "BlockQuote".

Usage

BlockQuote(blocks)

Arguments

blocks

a block object or list of block objects

Examples

BlockQuote(Plain("Hello R!"))

---

Bullet List

Description

Constructs a block object of type "BulletList".

Usage

BulletList(llblocks)

Arguments

llblocks

a list of lists of blocks

Examples

bullet_1 <- Plain("A")
bullet_2 <- Plain(Str("B"))
bullet_3 <- list(Plain(list(Str("C"))))
BulletList(list(bullet_1, bullet_2, bullet_3))

---

Combine Block Objects

Description

Objects of class "block" can be combined by using the generic default method "c" (combine).

Usage

## S3 method for class 'block'
c(...)

Arguments

...	objects to be concatenated.

Value

an list of "block" objects.

Examples

c(Header( "R Basics" ), Header("What is R?", level=2),
Plain(c(Emph("R"), Space(), "is a system for ", Strong("statistical computation"))))

---

Combine Inline Objects

Description

Objects of class "inline" can be combined by using the generic default method "c" (combine).

Usage

## S3 method for class 'inline'
c(...)

Arguments

...	objects to be concatenated.

Value

an list of "inline" objects.

Examples

c(Str("some"), Strong("text"))

---

Citation

Description

Constructs an object of type "Citation".

Usage

Citation(
  suffix,
  id,
  note_num = 0L,
  mode = "AuthorInText",
  prefix = list(),
  hash = 0L
)

Arguments

suffix	a inline object or list of inline objects
id	a character string (not visible in the text)
note_num	an integer
mode	a character string giving the citation mode, possible values are "AuthorInText", "SuppressAuthor" and "NormalCitation".
prefix	a inline object or list of inline objects
hash	an integer

---

Citation

Description

Constructs an inline object of type "Cite".

Usage

Cite(citation, x)

Arguments

citation	an object of type "Citation"
x	a inline object or a list of inline objects

Examples

ci <- Citation(suffix=list(Str("Suffix_1")),
               id="Citation_ID_1", prefix=list(Str("Prefix_1")))
Cite(ci, Str("some text"))

---

Inline Code

Description

Constructs an inline object of type "Code".

Usage

Code(code, name = "", language = NULL, line_numbers = FALSE, start_from = 1)

Arguments

code	a character string giving the inline code
name	an optional character string giving the name of the inline code chunk
language	an optional character string giving the programming language
line_numbers	a logical which controls if line numbers should be used
start_from	an integer giving the first line number

Examples

Code("lm(hello ~ world)", "my_r_inline_code", "R", TRUE, 0)
Code("lm(hello ~ world)")

---

Code Block

Description

Constructs a block object of type "CodeBlock".

Usage

CodeBlock(attr, code)

Arguments

attr	an object of type "Attr"
code	a character string containing the source code.

Examples

attr <- Attr("id", "Programming Language", list(c("key", "value")))
code <- "x <- 3\nprint('Hello R!')"
CodeBlock(attr, code)

---

Definition

Description

Constructs a Definition which can be used as an element of a "DefinitionList".

Usage

Definition(key, value)

Arguments

key	a inline object or list of inline objects
value	a block object or list of block objects

Examples

Definition("some key", Plain("some value"))

---

Definition List

Description

Constructs a block object of type "DefinitionList".

Usage

DefinitionList(x)

Arguments

x	a list of key value pairs, the key is a list of "inline" objects and the values are a list of lists of objects of type "block".

Details

In the pandoc API https://johnmacfarlane.net/BayHac2014/doc/pandoc-types/Text-Pandoc-Definition.html the DefinitionList is described as follows, each list item is a pair consisting of a term (a list of "inline" objects) and one or more definitions (each a list of blocks).

Examples

key <- list(Str("key"))
value <- list(list(Plain(list(Str("value")))))
DefinitionList(list(list(key, value), Definition("some key", Plain("some value"))))

---

Generic Block Container with Attributes

Description

Constructs a block object of type "Div".

Usage

Div(blocks, attr = Attr())

Arguments

blocks	a block object or list of block objects
attr	an object of type "Attr"

Examples

blocks <- Plain("Hello R!")
Div(blocks)

---

Create a new Document

Description

Constructs an object of type "document".

Usage

document()

Details

Each document has the following methods:

to_json()

Description
Returns the JSON representation of the document.

write(con, format = "markdown", writer = write.pandoc)

Description
Write the JSON-formatted AST to a connection.
Arguments

con	a connection object or a character string to which the document is written.
format	a character string giving the format (e.g. "latex", "html").
writer	an optional writer function, see write.pandoc.

Note
Any function with the three arguments x, con and format can be used as writer function.

append(x)

Description
Append a new block to the document.
Arguments

x	block object or list of block objects.

append_plain(x)

Description
For more information about the arguments see Plain.

append_para(x)

Description
For more information about the arguments see Para.

append_code_block(attr, code)

Description
For more information about the arguments see CodeBlock.

append_block_quote(blocks)

Description
For more information about the arguments see BlockQuote.

append_ordered_list(lattr, lblocks)

Description
For more information about the arguments see OrderedList.

append_bullet_list(lblocks)

Description
For more information about the arguments see BulletList.

append_definition_list(x)

Description
For more information about the arguments see DefinitionList.

append_header(x, level=1L, attr=Attr())

Description
For more information about the arguments see Header.

append_horizontal_rule()

Description
For more information about the arguments see HorizontalRule.

append_table(rows, col_names=NULL, aligns=NULL, col_width=NULL, caption=list())

Description
For more information about the arguments see Table.

append_div(blocks, attr)

Description
For more information about the arguments see Div.

append_null()

Description
For more information about the arguments see Null.

---

Emphasized Text

Description

Constructs an inline object of type "Emph".

Usage

Emph(x)

Arguments

x	a inline object or a list of inline objects

Examples

Emph("emphasize")

---

Filter JSON-formatted AST.

Description

Apply a filter on the JSON-formatted abstract syntax tree (AST).

Usage

filter(FUN, ..., input = stdin(), output = stdout())

Arguments

FUN	the function to be applied on the AST.
...	optional arguments to FUN.
input	a connection object or a character string from which the JSON-formatted AST is read.
output	a connection object or a character string to which the JSON-formatted AST is written.

---

Get Pandoc Path

Description

Get the path of pandoc.

Usage

get_pandoc_path()

---

Get Pandoc-Types Version

Description

Get the version of pandoc-types.

Usage

get_pandoc_types_version(type = c("numeric", "character"))

Arguments

type	a character giving the type of the return value.

Examples

get_pandoc_types_version()

---

Get Pandoc Version

Description

Get the version of pandoc.

Usage

get_pandoc_version(type = c("numeric", "character"))

Arguments

type	a character giving the type of the return value.

Examples

get_pandoc_version()

---

Header

Description

Constructs a block object of type "Header".

Usage

Header(x, level = 1L, attr = Attr())

Arguments

x	a inline object or a list of inline objects
level	an integer giving the level
attr	an object of type "Attr"

Examples

Header("My Header")

---

Horizontal Rule

Description

Constructs a block object of type "HorizontalRule".

Usage

HorizontalRule()

Examples

HorizontalRule()

---

Image

Description

Constructs an inline object of type "Image".

Usage

Image(target, text, caption = "", attr = Attr())

Arguments

target	a character string giving the target (hyper reference)
text	a inline object or a list of inline objects giving the visible part
caption	a character string describing the picture
attr	an optional object of type "Attr"

Details

Further Usage examples can be found in the README.

Examples

Image("https:://Rlogo.jpg", "some_text", "fig:some_caption")

---

Block Objects

Description

Tests if an object has the class attribute "block".

Usage

is.block(x)

Arguments

x	an object to be tested.

Value

a logical indicating if the provided object is of type "block".

Examples

is.block(as.block(NULL))

---

Inline Objects

Description

Tests if an object has the class attribute "inline".

Usage

is.inline(x)

Arguments

x	an object to be tested.

Value

a logical indicating if the provided object is of type "inline".

Examples

is.inline(as.inline(NULL))

---

Hard Line Break

Description

Constructs an inline object of type "LineBreak".

Usage

LineBreak()

Examples

LineBreak()

---

Hyperlink

Description

Constructs an inline object of type "Link".

Usage

Link(target, text, title = "", attr = Attr())

Arguments

target	a character string giving the target (hyper reference)
text	a inline object or a list of inline objects giving the visible part
title	an optional character string giving the title
attr	an optional object of type "Attr"

Details

Further Usage examples can be found in the README.

Examples

Link("https://cran.r-project.org/", "Text_Shown", "some title")

---

ListAttributes

Description

A constructor for pandoc list attributes.

Usage

ListAttributes(
  first_number = 1L,
  style = "DefaultStyle",
  delim = "DefaultDelim"
)

Arguments

first_number	an integer giving the first number of the list
style	a character string giving the style, possible values are "DefaultStyle", "Example", "Decimal", "LowerRoman", "UpperRoman", "LowerAlpha" and "UpperAlpha".
delim	a character string giving the delimiter, possible values are "DefaultDelim", "Period", "OneParen" and "TwoParens".

---

TeX Math

Description

Constructs an inline object of type "Math".

Usage

Math(x)

Arguments

x	a character string

Examples

Math("3*x^2")

---

Note

Description

Constructs an inline object of type "Note".

Usage

Note(x)

Arguments

x	a pandoc block object or a list of pandoc block objects

Examples

block <- Plain("x")
Note(block)

---

Nothing

Description

Constructs a block object of type "Null".

Usage

Null()

Examples

Null()

---

Ordered List

Description

Constructs a block object of type "OrderedList".

Usage

OrderedList(lattr, llblocks)

Arguments

lattr	a list of attributes
llblocks	a list of lists of blocks

Examples

ordered_1 <- Plain("A")
ordered_2 <- list(Plain(Str("B")))
ordered_3 <- list(Plain(list(Str("C"))))
OrderedList(ListAttributes(), ordered_1)
OrderedList(ListAttributes(), list(ordered_1, ordered_2, ordered_3))

---

Utility functions for testing filters

Description

Utility functions for testing filters

Usage

pandoc_to_json(file, from = "markdown")

pandoc_from_json(json, to = "markdown", exchange = c("file", "arg"))

Arguments

file	file name
from	markdown, html, latex or native
json	a JSON representation of the AST to be passed to pandoc
to	markdown, html, latex or native
exchange	a character string

---

Paragraph

Description

Constructs a block object of type "Para".

Usage

Para(x)

Arguments

x	a inline object or list of inline objects

Examples

Para("x")

---

Plain Text

Description

Constructs a block object of type "Plain", a plain paragraph.

Usage

Plain(x)

Arguments

x	a inline object or list of inline objects

Examples

Plain("x")

---

Quoted Text

Description

Constructs an inline object of type "Quoted".

Usage

Quoted(x, quote_type = "DoubleQuote")

Arguments

x	a inline object or a list of inline objects
quote_type	a character giving the quote type, valid types are "SingleQuote" and "DoubleQuote"

Examples

Quoted("some text", quote_type="SingleQuote")
Quoted("some text", quote_type="DoubleQuote")

---

Raw Inline

Description

Constructs an inline object of type "RawInline".

Usage

RawInline(format, x)

Arguments

format	a character string giving the format (e.g. "latex", "html")
x	a character string giving the inline

Examples

RawInline("latex", "some RawInline")

---

Set Pandoc Path

Description

Set the path to pandoc.

Usage

set_pandoc_path(path = "pandoc")

Arguments

path	a character giving the location of pandoc (default is "pandoc" which uses the pandoc set in the system path).

---

Small Caps Text

Description

Constructs an inline object of type "SmallCaps".

Usage

SmallCaps(x)

Arguments

x	a inline object or a list of inline objects

Examples

SmallCaps("The latex command for 'small caps' is 'textsc'!")

---

Soft Line Break

Description

Constructs an inline object of type "SoftBreak".

Usage

SoftBreak()

Examples

SoftBreak()

---

Inter-word space

Description

Constructs an inline object of type "Space".

Usage

Space()

Examples

Space()

---

Generic Inline Container with Attributes

Description

Constructs an inline object of type "Span".

Usage

Span(attr, inline)

Arguments

attr	an object of type "Attr"
inline	a inline object or a list of inline objects which will be shown

Examples

attr <- Attr("A", "B", list(c("C", "D")))
Span(attr, "some inline string")

---

Text (String)

Description

Constructs an inline object of type "Str".

Usage

Str(x)

Arguments

x	a character string

Details

To minimize the amount of unnecessary typing, pandoc filters automatically converts character strings to pandoc objects of type "Str" if needed. Furthermore, if a single inline object is provided where a list of inline objects is needed pandocfilters automatically converts this inline object into a list of inline objects. For example, the canonical way to emphasize the character string "some text" would be Emph(list(Str("some text"))) since single inline objects are automatically transformed to lists of inline objects, this is equivalent to Emph(Str("some text")). Since a character string is automatically transformed to an inline object, this is is equivalent to Emph("some string"). In short, whenever a list of inline objects is needed one can also use a single inline object or a character string.

Examples

Str("SomeString")

---

Strikeout Text

Description

Constructs an inline object of type "Strikeout".

Usage

Strikeout(x)

Arguments

x	a inline object or a list of inline objects

Examples

Strikeout("strikeout")

---

Strongly Emphasized Text

Description

Constructs an inline object of type "Strong".

Usage

Strong(x)

Arguments

x	a inline object or a list of inline objects

Examples

Strong("strong")

---

Subscripted Text

Description

Constructs an inline object of type "Subscript".

Usage

Subscript(x)

Arguments

x	a inline object or a list of inline objects

Examples

Subscript("some text written in superscript")

---

Superscripted Text

Description

Constructs an inline object of type "Superscript".

Usage

Superscript(x)

Arguments

x	a inline object or a list of inline objects

Examples

Superscript("some text written in superscript")

---

Table

Description

Constructs a block object of type "Table".

Usage

Table(
  rows,
  col_names = NULL,
  aligns = NULL,
  col_width = NULL,
  caption = list()
)

Arguments

rows	an object of class "matrix", "data.frame", "table" or a list of lists of pandoc objects of type "TableCell"
col_names	a list of objects of type "TableCell"
aligns	a character vector of alignments, possible values are “l” for left, “r” for right, “c” for center and “d” for default.
col_width	a numeric vector
caption	a inline object or a list of inline objects giving the caption

Details

Table, with caption, column alignments (required), relative column widths (0 = default), column headers (each a list of blocks), and rows (each a list of lists of blocks)

---

Table Cell

Description

Table cells is a constructor for plain table cells.

Usage

TableCell(x)

Arguments

x	a character string giving the content of the table cell

Details

In general table cells are a list of block elements, the constructor TableCell creates a plain table cell.

Examples

TableCell("Cell 1")

---

Write the JSON-formatted AST to a connection

Description

Write the JSON-formatted AST to a connection.

Usage

write.pandoc(json, file, format, exchange = c("arg", "file"))

Arguments

json	a JSON representation of the AST to be written out
file	a connection object or a character string to which the JSON-formatted AST is written
format	a character string giving the format (e.g. "latex", "html")
exchange	a character string

Details

If you want to apply a filter to the document before it get's written out, or your pandoc installation is not registered in the PATH it can be favorable to provide your own writer function to the document class.

---