Pandoc::Elements(3) create and process Pandoc documents

SYNOPSIS

The output of this script "hello.pl"


use Pandoc::Elements;
use JSON;
print Document({
title => MetaInlines [ Str "Greeting" ]
}, [
Header( 1, attributes { id => 'top' }, [ Str 'Hello' ] ),
Para [ Str 'Hello, world!' ],
])->to_json;

can be converted for instance to HTML with via 

    ./hello.pl | pandoc -f json -t html5 --standalone

an equivalent Pandoc Markdown document would be 

    % Greeting
    # Gruβ {.de}
    Hello, world!

DESCRIPTION

Pandoc::Elements provides utility functions to create abstract syntax trees (AST) of Pandoc <http://pandoc.org/> documents. Pandoc can convert the resulting data structure to many other document formats, such as HTML, LaTeX, ODT, and ePUB.

Please make sure to use at least Pandoc 1.12 when processing documents

See also module Pandoc::Filter, command line scripts pandocwalk and pod2pandoc, and the internal modules Pandoc::Walker, Pandoc::Filter::Lazy, and Pod::Simple::Pandoc.

EXPORTED FUNCTIONS

The following functions and keywords are exported by default:
  • Constructors for all Pandoc document element (block elements such as "Para" and inline elements such as "Emph", metadata elements and the ``Document'' in DOCUMENT ELEMENT).
  • Type keywords such as "Decimal" and "LowerAlpha" to be used as types in other document elements.
  • The helper following functions "pandoc_json", "attributes", "citation", and "element".

pandoc_json $json

Parse a JSON string, as emitted by pandoc in JSON format. This is the reverse to method "to_json".

attributes { key => $value, ... }

Maps a hash reference into an attributes list with id, classes, and ordered key-value pairs. The special keys "id" and "classes" are recognized but setting multi-value attributes or controlled order is not supported with this function. You can always manually create an attributes structure: 

    [ $id, [ @classes ], [ key => $value, ... ] ]

Elements with attributes (element accessor method "attr") also provide the accessor method "id", "classes", and "class". See Hash::MultiValue for easy access to key-value-pairs.

citation { ... }

A citation as part of document element Cite must be a hash reference with fields "citationID" (string), "citationPrefix" (list of inline elements) "citationSuffix" (list of inline elements), "citationMode" (one of "NormalCitation", C>AuthorInText>, "SuppressAuthor"), "citationNoteNum" (integer), and "citationHash" (integer). The helper method "citation" can be used to construct such hash by filling in default values and using shorter field names ("id", "prefix", "suffix", "mode", "note", and "hash"): 

    citation { 
        id => 'foo', 
        prefix => [ Str "see" ], 
        suffix => [ Str "p.", Space, Str "42" ]
    }
    # in Pandoc Markdown
    [see @foo p. 42]

element( $name => $content )

Create a Pandoc document element of arbitrary name. This function is only exported on request.

ELEMENTS

Document elements are encoded as Perl data structures equivalent to the JSON structure, emitted with pandoc output format "json". All elements are blessed objects that provide the following element methods and additional accessor methods specific to each element.

ELEMENT METHODS

to_json

Return the element as JSON encoded string. The following are equivalent: 

    $element->to_json;
    JSON->new->utf8->convert_blessed->encode($element);

name

Return the name of the element, e.g. ``Para'' for a paragraph element.

content

Return the element content. For most elements (Para, Emph, Str...) the content is an array reference with child elements. Other elements consist of multiple parts; for instance the Link element has a link text ("content") and a link target ("target") with "url" and "title".

is_block

True if the element is a Block element

is_inline

True if the element is an inline Inline element

is_meta

True if the element is a Metadata element

is_document

True if the element is a Document element

walk(...)

Walk the element tree with Pandoc::Walker

query(...)

Query the element to extract results with Pandoc::Walker

transform(...)

Transform the element tree with Pandoc::Walker

string

Returns a concatenated string of element content, leaving out all formatting.

BLOCK ELEMENTS

BlockQuote

Block quote, consisting of a list of blocks ("content") 

    BlockQuote [ @blocks ]

BulletList

Unnumbered list of items ("content"="items"), each a list of blocks 

    BulletList [ [ @blocks ] ]

CodeBlock

Code block (literal string "content") with attributes ("attr") 

    CodeBlock $attributes, $content

DefinitionList

Definition list, consisting of a list of pairs ("content"="items"), each a term ("term", a list of inlines) and one or more definitions ("definitions", a list of blocks). 

    DefinitionList [ @definitions ]
    # each item in @definitions being a pair of the form
        [ [ @inlines ], [ @blocks ] ]

Div

Generic container of blocks ("content") with attributes ("attr"). 

    Div $attributes, [ @blocks ]

Header

Header with "level" (integer), attributes ("attr"), and text ("content", a list of inlines). 

    Header $level, $attributes, [ @inlines ]

HorizontalRule

Horizontal rule 

    HorizontalRule

Null

Nothing 

    Null

OrderedList

Numbered list of items ("content"="items"), each a list of blocks), preceded by list attributes (start number, numbering style, and delimiter). 

    OrderedList [ $start, $style, $delim ], [ [ @blocks ] ]

Supported styles are "DefaultStyle", "Example", "Decimal", "LowerRoman", "UpperRoman", "LowerAlpha", and "UpperAlpha".

Supported delimiters are "DefaultDelim", "Period", "OneParen", and "TwoParens".

Para

Paragraph, consisting of a list of Inline elements ("content"). 

    Para [ $elements ]

Plain

Plain text, not a paragraph, consisting of a list of Inline elements ("content"). 

    Plain [ @inlines ]

RawBlock

Raw block with "format" and "content" string. 

    RawBlock $format, $content

Table

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

    Table [ @inlines ], [ @alignments ], [ @width ], [ @headers ], [ @rows ]

Possible alignments are "AlignLeft", "AlignRight", "AlignCenter", and "AlignDefault".

An example: 

    Table [Str "Example"], [AlignLeft,AlignRight], [0.0,0.0],
     [[Plain [Str "name"]]
     ,[Plain [Str "number"]]],
     [[[Plain [Str "Alice"]]
      ,[Plain [Str "42"]]]
     ,[[Plain [Str "Bob"]]
      ,[Plain [Str "23"]]]];

INLINE ELEMENTS

Cite

Citation, a list of "citations" and a list of inlines ("content"). See helper function ``citation'' in citation to construct citations. 

    Cite [ @citations ], [ @inlines ]

Code

Inline code, a literal string ("content") with attributes ("attr") 

    Code attributes { %attr }, $content

Emph

Emphasized text, a list of inlines ("content"). 

    Emph [ @inlines ]

Image

Image with alt text ("content", a list of inlines) and "target" (list of "url" and "title"). 

    Image [ @inlines ], [ $url, $title ]

LineBreak

Hard line break 

    LineBreak

Link

Hyperlink with link text ("content", a list of inlines) and "target" (list of "url" and "title"). 

    Link [ @inlines ], [ $url, $title ]

Math

TeX math, given as literal string ("content") with "type" (one of "DisplayMath" and "InlineMath"). 

    Math $type, $content

Note

Footnote or Endnote, a list of blocks ("content"). 

    Note [ @blocks ]

Quoted

Quoted text with quote "type" (one of "SingleQuote" and "DoubleQuote") and a list of inlines ("content"). 

    Quoted $type, [ @inlines ]

RawInline

Raw inline with "format" (a string) and "content" (a string). 

    RawInline $format, $content

SmallCaps

Small caps text, a list of inlines ("content"). 

    SmallCaps [ @inlines ]

Space

Inter-word space 

    Space

Span

Generic container of inlines ("content") with attributes ("attr"). 

    Span attributes { %attr }, [ @inlines ]

Str

Plain text, a string ("content"). 

    Str $text

Strikeout

Strikeout text, a list of inlines ("content"). 

    Strikeout [ @inlines ]

Strong

Strongly emphasized text, a list of inlines ("content"). 

    Strong [ @inlines ]

Subscript

Subscripted text, a list of inlines ("content"). 

    Supscript [ @inlines ]

Superscript

Superscripted text, a list of inlines ("content"). 

    Superscript [ @inlines ]

METADATA ELEMENTS

MetaBlocks

MetaBool

MetaInlines

MetaList

MetaMap

MetaString

DOCUMENT ELEMENT

Document

Root element, consisting of metadata hash ("meta") and document element array ("content"). 

    Document $meta, [ @blocks ]

TYPE KEYWORDS

The following document elements are only as used as type keywords in other document elements:
  • "SingleQuote", "DoubleQuote"
  • "DisplayMath", "InlineMath"
  • "AuthorInText", "SuppressAuthor", "NormalCitation"
  • "AlignLeft", "AlignRight", "AlignCenter", "AlignDefault"
  • "DefaultStyle", "Example", "Decimal", "LowerRoman", "UpperRoman", "LowerAlpha", "UpperAlpha"
  • "DefaultDelim", "Period", "OneParen", "TwoParens"

AUTHOR

Jakob Voβ <[email protected]>

COPYRIGHT AND LICENSE

Copyright 2014- Jakob Voβ

GNU General Public License, Version 2

This module is heavily based on Pandoc by John MacFarlane.

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