Network Working Group S. Leonard Internet-Draft Penango, Inc. Intended Status: Informational October 17, 2014 Expires: April 20, 2015 text/markdown Use Cases draft-seantek-text-markdown-use-cases-00 Abstract This document elaborates upon the text/markdown media type for use with Markdown, a family of plain text formatting syntaxes that optionally can be converted to formal markup languages such as HTML. Background information, local storage strategies, and additional syntax registrations are supplied. Status of this Memo This Internet-Draft is submitted in full conformance with the provisions of BCP 78 and BCP 79. Internet-Drafts are working documents of the Internet Engineering Task Force (IETF). Note that other groups may also distribute working documents as Internet-Drafts. The list of current Internet- Drafts is at http://datatracker.ietf.org/drafts/current/. Internet-Drafts are draft documents valid for a maximum of six months and may be updated, replaced, or obsoleted by other documents at any time. It is inappropriate to use Internet-Drafts as reference material or to cite them other than as "work in progress." Copyright Notice Copyright (c) 2014 IETF Trust and the persons identified as the document authors. All rights reserved. This document is subject to BCP 78 and the IETF Trust's Legal Provisions Relating to IETF Documents (http://trustee.ietf.org/license-info) in effect on the date of publication of this document. Please review these documents carefully, as they describe your rights and restrictions with respect to this document. Table of Contents 1. Dive Into Markdown . . . . . . . . . . . . . . . . . . . . . . 2 Leonard Exp. April 20, 2015 [Page 1] Internet-Draft text/markdown Use Cases October 2014 1.1. On Formats . . . . . . . . . . . . . . . . . . . . . . . . 2 1.2. Markdown Design Philosophy . . . . . . . . . . . . . . . . 4 1.3. Uses of Markdown . . . . . . . . . . . . . . . . . . . . . 5 1.4. Uses of Labeling Markdown Content as text/markdown . . . . 5 2. Strategies for Preserving Media Type and Parameters . . . . . 6 2.1. Map to Attributes . . . . . . . . . . . . . . . . . . . . . 6 2.2. Store Headers in Adjacent File . . . . . . . . . . . . . . 6 2.3. "Arm" Content with MIME Headers . . . . . . . . . . . . . . 7 2.4. Create a Local Batch Script . . . . . . . . . . . . . . . . 7 2.5. Process the Markdown . . . . . . . . . . . . . . . . . . . 7 2.6. Rely on Context . . . . . . . . . . . . . . . . . . . . . . 7 3. Registration Templates for Common Markdown Syntaxes . . . . . 8 3.1. MultiMarkdown . . . . . . . . . . . . . . . . . . . . . . . 8 3.2. GitHub Flavored Markdown . . . . . . . . . . . . . . . . . 10 3.3. Pandoc . . . . . . . . . . . . . . . . . . . . . . . . . . 11 3.4. Fountain (Fountain.io) . . . . . . . . . . . . . . . . . . 14 3.5. CommonMark . . . . . . . . . . . . . . . . . . . . . . . . 15 3.6. kramdown-rfc2629 (Markdown for RFCs) . . . . . . . . . . . 16 3.7. rfc7328 (Pandoc2rfc) . . . . . . . . . . . . . . . . . . . 17 4. Examples for Common Markdown Syntaxes . . . . . . . . . . . . 17 4.1. MultiMarkdown . . . . . . . . . . . . . . . . . . . . . . . 17 4.2. GitHub Flavored Markdown . . . . . . . . . . . . . . . . . 18 4.3. Pandoc . . . . . . . . . . . . . . . . . . . . . . . . . . 18 4.4. Fountain (Fountain.io) . . . . . . . . . . . . . . . . . . 18 4.5. CommonMark . . . . . . . . . . . . . . . . . . . . . . . . 18 4.6. kramdown-rfc2629 (Markdown for RFCs) . . . . . . . . . . . 18 4.7. rfc7328 (Pandoc2rfc) . . . . . . . . . . . . . . . . . . . 18 5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 18 6. Security Considerations . . . . . . . . . . . . . . . . . . . . 18 7. References . . . . . . . . . . . . . . . . . . . . . . . . . . 18 7.1. Normative References . . . . . . . . . . . . . . . . . . . 18 7.2. Informative References . . . . . . . . . . . . . . . . . . 18 Author's Address . . . . . . . . . . . . . . . . . . . . . . . . . 20 1. Dive Into Markdown This document serves as an informational companion to [MDMTREG], the text/markdown media type registration. It should be considered jointly with [MDMTREG]. "Sometimes the truth of a thing is not so much in the think of it, but in the feel of it." --Stanley Kubrick 1.1. On Formats In computer systems, textual data is stored and processed using a continuum of techniques. On the one end is plain text: a linear Leonard Exp. April 20, 2015 [Page 2] Internet-Draft text/markdown Use Cases October 2014 sequence of characters in some character set (code), possibly interrupted by line breaks, page breaks, or other control characters. Plain text provides /some/ fixed facilities for formatting instructions, namely codes in the character set that have meanings other than "represent this character on the output medium"; however, these facilities are not particularly extensible. Compare with [RFC6838] Section 4.2.1. Applications may neuter the effects of these special characters by prohibiting them or by ignoring their dictated meanings, as is the case with how modern applications treat most control characters in US-ASCII. On this end, any text reader or editor that interprets the character set can be used to see or manipulate the text. If some characters are corrupted, the corruption is unlikely to affect the ability of a computer system to process the text (even if the human meaning is changed). On the other end is binary format: a sequence of instructions intended for some computer application to interpret and act upon. Binary formats are flexible in that they can store non-textual data efficiently (perhaps storing no text at all, or only storing certain kinds of text for very specialized purposes). Binary formats require an application to be coded specifically to handle the format; no partial interoperability is possible. Furthermore, if even one byte or bit are corrupted in a binary format, it may prevent an application from processing any of the data correctly. Between these two extremes lies formatted text, i.e., text that includes non-textual information coded in a particular way, that affects the interpretation of the text by computer programs. Formatted text is distinct from plain text and binary format in that the non-textual information is encoded into textual characters, which are assigned specialized meanings /not/ defined by the character set. With a regular text editor and a standard keyboard (or other standard input mechanism), a user can enter these textual characters to express the non-textual meanings. For example, a character like "<" no longer means "LESS-THAN SIGN"; it means the start of a tag or element that affects the document in some way. On the formal end of the spectrum is markup, a family of languages for annotating a document in such a way that the annotations are syntactically distinguishable from the text. Markup languages are (reasonably) well-specified and tend to follow (mostly) standardized syntax rules. Examples of markup languages include SGML, HTML, XML, and LaTeX. Standardized rules lead to interoperability between markup processors, but a skill requirement for new (human) users of the language that they learn these rules in order to do useful work. This imposition makes markup less accessible for non-technical users (i.e., users who are unwilling or unable to invest in the requisite skill development). Leonard Exp. April 20, 2015 [Page 3] Internet-Draft text/markdown Use Cases October 2014 informal /---------formatted text----------\ formal <------v-------------v-------------v-----------------------v----> plain text informal markup formal markup binary format (Markdown) (HTML, XML, etc.) Figure 1: Degrees of Formality in Data Storage Formats for Text On the informal end of the spectrum are lightweight markup languages. In comparison with formal markup like XML, lightweight markup uses simple syntax, and is designed to be easy for humans to enter with basic text editors. Markdown, the subject of this document, is an /informal/ plain text formatting syntax that is intentionally targeted at non-technical users (i.e., users upon whom little to no skill development is imposed) using unspecialized tools (i.e., text boxes). Jeff Atwood once described these informal markup languages as "humane" [HUMANE]. 1.2. Markdown Design Philosophy Markdown specifically is a family of syntaxes that are based on the original work of John Gruber with substantial contributions from Aaron Swartz, released in 2004 [MARKDOWN]. Since its release a number of web or web-facing applications have incorporated Markdown into their text entry systems, frequently with custom extensions. Fed up with the complexity and security pitfalls of formal markup languages (e.g., HTML5) and proprietary binary formats (e.g., commercial word processing software), yet unwilling to be confined to the restrictions of plain text, many users have turned to Markdown for document processing. Whole toolchains now exist to support Markdown for online and offline projects. Informality is a bedrock premise of Gruber's design. Gruber created Markdown after disastrous experiences with strict XML and XHTML processing of syndicated feeds. In Mark Pilgrim's "thought experiment", several websites went down because one site included invalid XHTML in a blog post, which was automatically copied via trackbacks across other sites [DIN2MD]. These scenarios led Gruber to believe that clients (e.g., web browsers) SHOULD try to make sense of data that they receive, rather than rejecting data simply because it fails to adhere to strict, unforgiving standards. (In [DIN2MD], Gruber compared Postel's Law [RFC0793] with the XML standard, which says: "Once a fatal error is detected [...] the processor MUST NOT continue normal processing" [XML1.0-5].) As a result, there is no such thing as "invalid" Markdown; there is no standard demanding adherence to the Markdown syntax; there is no governing body that guides or impedes its development. If the Markdown syntax does not result in the "right" output (defined as output that the author wants, not output that adheres to some dictated system of rules), Leonard Exp. April 20, 2015 [Page 4] Internet-Draft text/markdown Use Cases October 2014 Gruber's view is that the author either should keep on experimenting, or should change the processor to address the author's particular needs (see [MARKDOWN] Readme and [MD102b8] perldoc; see also [CATPICS]). 1.3. Uses of Markdown Since its introduction in 2004, Markdown has enjoyed remarkable success. Markdown works for users for three key reasons. First, the markup instructions (in text) look similar to the markup that they represent; therefore the cognitive burden to learn the syntax is low. Second, the primary arbiter of the syntax's success is *running code*. The tool that converts the Markdown to a presentable format, and not a series of formal pronouncements by a standards body, is the basis for whether syntactic elements matter. Third, Markdown has become something of an Internet meme [INETMEME], in that Markdown gets received, reinterpreted, and reworked as additional communities encounter it. There are communities that are using Markdown for scholarly writing [CITE], for screenplays [FOUNTAIN], for mathematical formulae [CITE], and even for music annotation [CITE]. Clearly, a screenwriter has no use for specialized Markdown syntax for mathematicians; likewise, mathematicians do not need to identify characters or props in common ways. The overall gist is that all of these communities can take the common elements of Markdown (which are rooted in the common elements of HTML circa 2004) and build on them in ways that best fit their needs. 1.4. Uses of Labeling Markdown Content as text/markdown The primary purpose of an Internet media type is to label "content" on the Internet, as distinct from "files". Content is any computer- readable format that can be represented as a primary sequence of octets, along with type-specific metadata (parameters) and type- agnostic metadata (protocol dependent). From this description, it is apparent that appending ".markdown" to the end of a filename is not a sufficient means to identify Markdown. Filenames are properties of files in file systems, but Markdown frequently exists in databases or content management systems (CMSes) where the file metaphor does not apply. One CMS [RAILFROG] uses media types to select appropriate processing, so a media type is necessary for the safe and interoperable use of Markdown. Unlike complete HTML documents, [MDSYNTAX] provides no means to include metadata into the content stream. Several derivative flavors have invented metadata incorporation schemes (e.g., [MULTIMD]), but these schemes only address specific use cases. In general, the metadata must be supplied via supplementary means in an encapsulating protocol, format, or convention. The relationship between the content Leonard Exp. April 20, 2015 [Page 5] Internet-Draft text/markdown Use Cases October 2014 and the metadata is not directly addressed here or in [MDMTREG]; however, by identifying Markdown with a media type, Markdown content can participate as a first-class citizen with a wide spectrum of metadata schemes. Finally, registering a media type through the IETF process is not trivial. Markdown can no longer be considered a "vendor"-specific innovation, but the registration requirements even in the vendor tree have proven to be overly burdensome for most Markdown implementers. Moreover, registering hundreds of Markdown variants with distinct media types would impede interoperability: virtually all Markdown content can be processed by virtually any Markdown processor, with varying degrees of success. The goal of [MDMTREG] is to reduce all of these burdens by having one media type that accommodates diversity and eases registration. 2. Strategies for Preserving Media Type and Parameters The purpose of this document and [MDMTREG] is to promote interoperability between different Markdown-related systems, preserving the author's intent. While [MARKDOWN] was designed by Gruber in 2004 as a simple way to write blog posts and comments, as of 2014 Markdown and its derivatives are rapidly becoming the formats of record for many communities and use cases. While an individual member of (or software tool for) a community can probably look at some "Markdown" and declare its meaning intuitively obvious, software systems in different communities (or different times) need help. [MDSYNTAX] does not have a signaling mechanism like , so tagging Markdown internally is simply out of the question. Once tags or metadata are introduced, the content is no longer "just" Markdown. It is hoped that the media type and parameters in [MDMTREG] will provide this missing context for the foreseeable future. This section covers strategies for how an application might preserve this metadata information when it leaves the domain of IETF protocols. 2.1. Map to Attributes This strategy is to map the media type and parameters to "attributes" or "forks" in the local convention. Firstly, Markdown content saved to a file SHOULD have an appropriate file extension such as .md or .markdown, which serves to disambiguate it from other kinds of files. Many modern filesystems permit "extended attributes", "alternate data streams", or "resource forks". Some version control systems permit named properties, which are analogous to a filesystem's extended attributes. 2.2. Store Headers in Adjacent File Leonard Exp. April 20, 2015 [Page 6] Internet-Draft text/markdown Use Cases October 2014 This strategy is to save the Markdown content in a first file, and to save the metadata (specifically the Content-Type: header) in a second file with a filename that is rationally related to the first filename. For example, if the first file is named "readme.markdown", the second file could be named "readme.markdown.headers". (If stored in a database, the analogy would be to store the metadata in a second table with a field that is a key to the first table.) 2.3. "Arm" Content with MIME Headers This strategy is to save the Markdown content along with its headers in a file, "arming" the content by prepending the MIME headers (specifically the Content-Type: header). It should be appreciated that the file is no longer a "Markdown file"; rather, it is an Internet Message Format file (e.g., [RFC5322]) with a Markdown content part. 2.4. Create a Local Batch Script This strategy is to translate the processing instructions inferred from the syntax and output-type parameters into a sequence of commands in the local convention, storing those commands in a batch script. For example, when a MIME-aware client stores some Markdown to disk, the client can save a Makefile in the same directory with commands that are appropriate (and safe) for the local system. 2.5. Process the Markdown This strategy is to process the Markdown into the formal markup, which eliminates ambiguities. Once the Markdown is processed into (for example) valid XHTML, an application can save a file as "doc.xhtml" with no further loss of metadata. Of course, depending on the output-type, this process may not be reversible. 2.6. Rely on Context This last strategy is to use or create context to determine how to interpret the Markdown. For example, Markdown content that is of the Fountain.io type [FOUNTAIN] could be saved with the filename "script.fountain" instead of "script.markdown". Alternatively, scripts could be stored in a "/screenplays" directory while other kinds of Markdown could be stored elsewhere. For reasons that should be intuitively obvious, this method is the most error-prone. "Context" can be easily lost over time, and the trend of passing Markdown between systems--taking them *out* of context--is increasing. Leonard Exp. April 20, 2015 [Page 7] Internet-Draft text/markdown Use Cases October 2014 3. Registration Templates for Common Markdown Syntaxes The purpose of this section is to register certain syntaxes in the Markdown Syntaxes Registry [MDMTREG] because they illustrate particularly interesting use cases or are broadly applicable to the Internet community; thus, these syntaxes would benefit from the level of review associated with publication as IETF documents. [[TODO: The maintainers of these syntaxes were consulted and provided valuable input into these registrations.]] [[NB: This section was rushed through. It is meant to get the gist until the next draft(s).]] [[NB: Different registration syntaxes in the Extensions field are experimented with.]] [[NB: The Documentation sub-field in Extensions may be optional if it merely duplicates existing information.]] [[NB: Output types annotated with * are not registered as of the time of this draft; they ought to be registered to ensure interoperability.]] 3.1. MultiMarkdown Identifier: MultiMarkdown Description: MultiMarkdown (MMD) is a superset of "Original". It adds multiple syntax features (tables, footnotes, and citations, to name a few), in addition various output formats. Additionally, it builds in "smart" typography for various languages (proper left- and right-sided quotes, for example). Documentation: Community of Use: General. Versions: Identifier: 4 Description: The fourth revision of MultiMarkdown, released in 2014. The version "4" SHOULD NOT be specified until further notice; is is only documented for completeness (in case Penney revises the syntax with material contradictions). Extensions: Identifier: latex_mode Leonard Exp. April 20, 2015 [Page 8] Internet-Draft text/markdown Use Cases October 2014 Syntax: Enabled, with String: "memoir" or "beamer" Description: If the output-type is LaTeX, and a LaTeX header block is not included, this extension sets the document class. This extension has no effect if the output-type is not LaTeX or if a LaTeX header block already specifies the mode. Documentation: Identifier: force Syntax: Enabled, with String: "full" or "snippet" Description: Forces either "full": a complete document, even if it does not contain enough metadata to otherwise trigger a complete document; or "snippet": a snippet, meaning that header and footer information is left out. Documentation: Identifier: process_html Syntax: Enabled Description: Process the text included within HTML tags in the source document. Documentation: > random_footnote_identifiers Syntax: Enabled Description: Use random identifier numbers for footnotes. Useful when you might combine multiple HTML documents together, e.g. in a weblog. > CriticMarkup @ ES ("a", "r", or "a&r") |Accept ("a"), reject ("r"), or highlight changes ("a&r") using |CriticMarkup syntax. When disabled, MultiMarkdown will leave the |CriticMarkup syntax in place. ~ ~ ~ > no_smart @ E |Disables "smart" typography, similar to John Gruber's SmartyPants |program. "Smart" typography is enabled by default in MultiMarkdown. ~ Leonard Exp. April 20, 2015 [Page 9] Internet-Draft text/markdown Use Cases October 2014 > no_notes % E |Disables footnotes and similar markup (glossary, citations). ~ > no_labels % E |Disables adding id attributes to headers in HTML. ~ Identifier: no_mask Syntax: Enabled Description: Disables masking of e-mail addresses when creating HTML. Documentation: [[TODO: continue analysis with --help_all.]] Anticipated Output Types: text/html text/x-opml (or text/opml+xml)* text/tex* application/vnd.oasis.opendocument.text Specifically Flat OpenDocument Text (in XML) Additional Fragment Identifiers: See . #meta Metadata. #meta# Metadata; is the key string. Responsible Parties: (individual) Fletcher T. Penney Currently Maintained? Yes Implementations: Name: MultiMarkdown Type: Processor References: Purpose: Converts Markdown to various output formats, with very interesting extensions, using peg-markdown in a fast, portable C implementation. 3.2. GitHub Flavored Markdown Identifier: GFM Leonard Exp. April 20, 2015 [Page 10] Internet-Draft text/markdown Use Cases October 2014 Description: "Original" with the following differences: 1. Multiple underscores in words 2. URL (URI) autolinking 3. Strikethrough 4. Fenced code blocks 5. Syntax highlighting 6. Tables (- for rows; | for columns; : for alignment) 7. Only some HTML allowed; sanitization is integral to the format Documentation: Community of Use: GitHub users (software developers, Git users) Anticipated Output Types: text/html Responsible Parties: (corporate) GitHub, Inc. [[Vicent Marti ??]] Currently Maintained? Yes Implementations: Name: GitHub Type: Web Application References: Purpose: Distributed revision control and source code management. 3.3. Pandoc Identifier: pandoc Description: Markdown is designed to be easy to write and to read: the content should be publishable as-is, as plain text, without looking like it has been marked up with tags or formatting instructions. Yet whereas "Original" has HTML generation in mind, pandoc is designed for multiple output formats. Thus, while pandoc allows the embedding of raw HTML, it discourages it, and provides other, non- HTMLish ways of representing important document elements like definition lists, tables, mathematics, and footnotes. Documentation: Leonard Exp. April 20, 2015 [Page 11] Internet-Draft text/markdown Use Cases October 2014 Community of Use: General. Extensions: [[Stuff to turn off:]] > no_escaped_line_breaks > no_blank_before_header > no_header_attributes > no_auto_identifiers > no_implicit_header_references > no_blank_before_blockquote > no_fenced_code_blocks > no_fenced_code_attributes > no_line_blocks > no_fancy_lists > no_startnum > no_definition_lists > no_example_lists > no_table_captions > no_simple_tables > no_multiline_tables > no_grid_tables > no_pipe_tables > no_pandoc_title_block > no_yaml_metadata_block > no_all_symbols_escapable > no_intraword_underscores > no_strikeout > no_superscript > no_subscript > no_inline_code_attributes > no_tex_math_dollars > no_raw_html > no_markdown_in_html_blocks > no_native_divs > no_native_spans > no_raw_tex > no_latex_macros > no_implicit_figures > no_footnotes > no_inline_notes > no_citations [[New stuff:]] > lists_without_preceding_blankline > hard_line_breaks Leonard Exp. April 20, 2015 [Page 12] Internet-Draft text/markdown Use Cases October 2014 > ignore_line_breaks > tex_math_single_backslash > tex_match_double_backslash > markdown_attribute > mmd_title_block > abbreviations > autolink_bare_uris > ascii_identifiers > link_attributes > mmd_header_identifiers > compact_definition_lists [[Output controls:]] > epub_version: ES ("2" / "3") |When the output-type is application/epub+zip, this extension |specifies the EPUB version to emit. Anticipated Output Types: text/html application/xhtml+xml application/epub+zip* [[This media type does not distinguish between v2 and v3.]] text/tex* text/plain text/rtf text/x-opml* [[InDesign Markup Language, icml]]* text/x-asciidoc (AsciiDoc)* application/json [[native (Haskell)]]* text/x-rst* [[man]]* [[mediawiki]] [[dokuwiki]] [[textile]] [[Emacs org-mode]] [[GNU Texinfo]] application/docbook+xml* application/vnd.oasis.opendocument.text application/vnd.openxmlformats-officedocument. wordprocessingml.document [[Haddock Markup]] [[FictionBook fb2, fb3]] [[slidy, slideous, dzslides, revealjs, s5]] [[custom lua writer]] Additional Fragment Identifiers: Leonard Exp. April 20, 2015 [Page 13] Internet-Draft text/markdown Use Cases October 2014 #id# Identifier in attribute; is the identifier in the {# .class ...} production. Used for Header Identifiers and Code Block Identifiers. Not used for the (no_)auto_identifiers extension: (no_)auto_identifiers only modifies the output, for certain output types. #ptb Pandoc Title Block. #ptb#t Pandoc Title Block - Title. #ptb#a Pandoc Title Block - Author(s). #ptb#d Pandoc Title Block - Date. #ymb YAML Metadata Block. #ymb# YAML Metadata Block; is the key string. #mtb MultiMarkdown Title Block (Metadata). #mtb# MultiMarkdown Title Block (Metadata); is the key string. Responsible Parties: (individual) Prof. John MacFarlane Currently Maintained? Yes Implementations: Name: pandoc Versions: 1.13.1 Type: Processor References: Purpose: Convert files from Markdown to a wide variety of markup formats; pandoc is your swiss-army knife. 3.4. Fountain (Fountain.io) Identifier: Fountain Versions: Identifier: 1.1 Description: Version 1.1 was released March 14, 2014. [[? The version "1.1" SHOULD NOT be specified until further notice; it is only documented for completeness.]] Description: Fountain is a simple markup syntax for writing, editing and sharing screenplays in plain, human-readable text. Fountain allows you to work on your screenplay anywhere, on any computer or tablet, using any software that edits text files. Documentation: Leonard Exp. April 20, 2015 [Page 14] Internet-Draft text/markdown Use Cases October 2014 Community of Use: Screenwriters (mass media production). Anticipated Output Types: application/pdf text/fdx+xml* [[Final Draft FDX format]] Additional Fragment Identifiers: See and . #TitlePage Title Page (acts as metadata). #TitlePage# Title Page; is the key string. #Section# *(#) Section or subsection. The .. productions are the text of the Section line, with whitespace trimmed from both ends. Sub-sections (sections with multiple # at at the beginnings) are addressed hierarchically by preceding the sub-section with higher-order sections. If the section hierarchy "skips", e.g., # to ###, use a blank section name, e.g., #Section#ACT%20I##PATIO%20SCENE. Responsible Parties: (individual) Stu Maschwitz (individual) John August Currently Maintained? Yes 3.5. CommonMark Identifier: CommonMark Description: CommonMark is a standard, unambiguous syntax specification for Markdown, along with a suite of comprehensive tests to validate Markdown implementations against this specification. The responsible parties believe this is necessary, even essential, for the future of Markdown. Compared to "Original", CommonMark is much longer and in a few instances contradicts "Original" based on seasoned experience. Although CommonMark specifically does not mandate any particular encoding for the input content, CommonMark draws in more of Unicode, UTF-8, and HTML (including HTML5) than "Original". Documentation: Leonard Exp. April 20, 2015 [Page 15] Internet-Draft text/markdown Use Cases October 2014 Community of Use: General. Versions: Identifier: 2 Description: Version 2 was released September 19, 2014. [[? The version "2" SHOULD NOT be specified until further notice; it is only documented for completeness.]] Anticipated Output Types: text/html Responsible Parties: (individual) John MacFarlane (individual) David Greenspan (individual) Vicent Marti (individual) Neil Williams (individual) Benjamin Dumke-von der Ehe (individual) Jeff Atwood Implementations: Name: stmd Type: Processor References: Purpose: Converts CommonMark Markdown to HTML in a C99 implementation and a JavaScript implementation. 3.6. kramdown-rfc2629 (Markdown for RFCs) Identifier: kramdown-rfc2629 Description: kramdown is a markdown parser by Thomas Leitner, which has a number of backends for generating HTML, Latex, and Markdown again. kramdown-rfc2629 is an additional backend to that: It allows the generation of XML2RFC XML markup (also known as RFC 2629 compliant markup). Documentation: Community of Use: Anybody who is writing Internet-Drafts and RFCs in the IETF and prefers (or has co-authors who prefer) to do part of their work in Markdown. Anticipated Output Types: text/xml (application/xml) The output is in xml2rfc syntax. Responsible Parties: Leonard Exp. April 20, 2015 [Page 16] Internet-Draft text/markdown Use Cases October 2014 (individual) Carsten Bormann Implementations: Name: kramdown-rfc2629 Type: Processor References: Purpose: Converts the input into xml2rfc syntax. 3.7. rfc7328 (Pandoc2rfc) Identifier: rfc7328 Description: Pandoc2rfc allows authors to write in "pandoc" that is then transformed to XML and given to xml2rfc. The conversions are, in a way, amusing, as we start off with (almost) plain text, use elaborate XML, and end up with plain text again. Documentation: RFC 7328; Community of Use: Anybody who is writing Internet-Drafts and RFCs in the IETF and prefers (or has co-authors who prefer) to do part of their work in this syntax, which is a profile of "pandoc" plus a specific workflow involving additional tools. Anticipated Output Types: text/plain The output is in Internet-Draft (or RFC) format, in US-ASCII encoding. Responsible Parties: (individual) R. (Miek) Gieben Implementations: Name: pandoc2rfc Type: Bundle of Scripts and Templates References: Purpose: By following the included instructions, a variant of the pandoc syntax is converted into xml2rfc, which is then converted into Internet-Draft. 4. Examples for Common Markdown Syntaxes This section provides examples of the syntaxes registered in Appendix C. 4.1. MultiMarkdown Leonard Exp. April 20, 2015 [Page 17] Internet-Draft text/markdown Use Cases October 2014 4.2. GitHub Flavored Markdown 4.3. Pandoc 4.4. Fountain (Fountain.io) 4.5. CommonMark 4.6. kramdown-rfc2629 (Markdown for RFCs) 4.7. rfc7328 (Pandoc2rfc) [[TODO: complete.]] 5. IANA Considerations IANA is asked to register the syntaxes specified in Section 3 in the Markdown Syntaxes Registry. 6. Security Considerations See the respective syntax descriptions and output media type registrations for their respective security considerations. 7. References 7.1. Normative References [MARKDOWN] Gruber, J., "Daring Fireball: Markdown", December 2004, . [MDSYNTAX] Gruber, J., "Daring Fireball: Markdown Syntax Documentation", December 2004, . [MDMTREG] Leonard, S., "The text/markdown Media Type", draft-ietf- appsawg-text-markdown-03 (work in progress), October 2014. [RFC5147] Wilde, E. and M. Duerst, "URI Fragment Identifiers for the text/plain Media Type", RFC 5147, April 2008. [RFC5322] Resnick, P., Ed., "Internet Message Format", RFC 5322, October 2008. 7.2. Informative References Leonard Exp. April 20, 2015 [Page 18] Internet-Draft text/markdown Use Cases October 2014 [HUMANE] Atwood, J., "Is HTML a Humane Markup Language?", May 2008, . [DIN2MD] Gruber, J., "Dive Into Markdown", March 2004, . [MD102b8] Gruber, J., "[ANN] Markdown.pl 1.0.2b8", May 2007, , . [CATPICS] Gruber, J. and M. Arment, "The Talk Show: Ep. 88: 'Cat Pictures' (Side 1)", July 2014, . [INETMEME] Solon, O., "Richard Dawkins on the internet's hijacking of the word 'meme'", June 2013, , . [MULTIMD] Penney, F., "MultiMarkdown", April 2014, . [PANDOC] MacFarlane, J., "Pandoc", 2014, . [RAILFROG] Railfrog Team, "Railfrog", April 2009, . [RFC0793] Postel, J., "Transmission Control Protocol", STD 7, RFC 793, September 1981. [RFC4263] Lilly, B., "Media Subtype Registration for Media Type text/troff", RFC 4263, January 2006. [RFC6838] Freed, N., Klensin, J., and T. Hansen, "Media Type Specifications and Registration Procedures", BCP 13, RFC 6838, January 2013. [XML1.0-5] Bray, T., Paoli, J., Sperberg-McQueen, M., Maler, E., and F. Yergeau, "Extensible Markup Language (XML) 1.0 (Fifth Edition)", World Wide Web Consortium Recommendation REC- xml-20081126, November 2008, . [FOUNTAIN] Maschwitz, S. and J. August, "Fountain | A markup language for screenwriting.", 2014, . Leonard Exp. April 20, 2015 [Page 19] Internet-Draft text/markdown Use Cases October 2014 [FTSYNTAX] Maschwitz, S. and J. August, "Syntax - Fountain | A markup language for screenwriting.", 1.1, March 2014, . Author's Address Sean Leonard Penango, Inc. 5900 Wilshire Boulevard 21st Floor Los Angeles, CA 90036 USA EMail: dev+ietf@seantek.com URI: http://www.penango.com/ Leonard Exp. April 20, 2015 [Page 20]