Punctuation

Typesafe parsing and rendering of markdown

Punctuation provides a convenient representation of Markdown which disambiguates between inline- and block-level content, with converters to Honeycomb HTML and Escapade ANSI-rendered text.

Features

• parse Markdown content
• use different types for inline- and block-level content
• static typechecking of Markdown using interpolated strings
• support for substitutions of different types as formatted Markdown
• simple Scala AST representing Markdown
• convert inline- or block-level Markdown to HTML (using Honeycomb)
• convert Markdown to styled ANSI terminal text (using Escapade)

Availability

Getting Started

Markdown may be read from a source such as a string or file with the Markdown.parse method. For example,

import punctuation.*
val md = Markdown.parse(t"## This is a subheading")

will return an instance of Markdown[Block], which is a wrapper for a sequence of block-level Markdown AST elements. In the example above, the result would be equal to, Markdown(Heading(2, Textual(t"This is a subheading"))).

Block-level AST elements are:

• ThematicBreak()
• Paragraph(inline*)
• Heading(level, inline*)
• FencedCode(lang, meta, text)
• BulletList(numbered, loose, items*)
• BlockQuote(block*)
• Reference(id, location)
• Table(parts*)

Using Honeycomb a Markdown[Block] instance may be converted to HTML just by calling the html extension method on it. This extension method returns an instance of Seq[Html[Flow]].

Inline Markdown

Often block-level Markdown elements are not desired, and the subset of Markdown that is valid in "inline" contexts is required. The Markdown.parseInline method will parse an inline fragment of Markdown, returning an instance of Markdown[Inline].

Inline AST elements are:

• Break()
• Emphasis(inline*)
• HtmlNode(text)
• Image(alt, src)
• Code(text)
• Strong(inline*)
• Textual(text)
• Link(location, inline*)

Likewise, a Markdown[Inline] instance can be converted to HTML with the html extension method. Since inline Markdown uses a more limited set of HTML tags, this method returns a Seq[Html[Phrasing]] which allows it to be embedded within nodes such as P, which would not be the case for block-level Markdown converted to HTML.

md"" Interpolator

In addition to parsing Markdown at runtime, it's possible to construct Markdown literals with the md"" interpolator. This is as simple as writing markdown inside quotes preceded by md, and it will be parsed at compiletime. For example, md"This is _emphasised_."

The type of a md"" literal will depend upon its content. If it includes block-level elements, its return type will be Markdown[Block], whereas if it uses only inline elements, it will be typed as Markdown[Inline].

Any errors in the Markdown content will be detected at compiletime, causing compile errors.

Substitutions into Markdown literals are also supported, provided the type of the substitution can be converted to Markdown, and can appear at the position it's substituted. Conversion of a particular type to Markdown is permitted by the existence of a contextual typeclass instance.

Status

Punctuation is classified as fledgling. For reference, Soundness projects are categorized into one of the following five stability levels:

• embryonic: for experimental or demonstrative purposes only, without any guarantees of longevity
• fledgling: of proven utility, seeking contributions, but liable to significant redesigns
• maturescent: major design decisions broady settled, seeking probatory adoption and refinement
• dependable: production-ready, subject to controlled ongoing maintenance and enhancement; tagged as version 1.0.0 or later
• adamantine: proven, reliable and production-ready, with no further breaking changes ever anticipated

Projects at any stability level, even embryonic projects, can still be used, as long as caution is taken to avoid a mismatch between the project's stability level and the required stability and maintainability of your own project.

Punctuation is designed to be small. Its entire source code currently consists of 666 lines of code.

Building

Punctuation will ultimately be built by Fury, when it is published. In the meantime, two possibilities are offered, however they are acknowledged to be fragile, inadequately tested, and unsuitable for anything more than experimentation. They are provided only for the necessity of providing some answer to the question, "how can I try Punctuation?".

1. Copy the sources into your own project

   Read the fury file in the repository root to understand Punctuation's build structure, dependencies and source location; the file format should be short and quite intuitive. Copy the sources into a source directory in your own project, then repeat (recursively) for each of the dependencies.

   The sources are compiled against the latest nightly release of Scala 3. There should be no problem to compile the project together with all of its dependencies in a single compilation.

2. Build with Wrath

   Wrath is a bootstrapping script for building Punctuation and other projects in the absence of a fully-featured build tool. It is designed to read the fury file in the project directory, and produce a collection of JAR files which can be added to a classpath, by compiling the project and all of its dependencies, including the Scala compiler itself.

   Download the latest version of wrath, make it executable, and add it to your path, for example by copying it to /usr/local/bin/.

   Clone this repository inside an empty directory, so that the build can safely make clones of repositories it depends on as peers of punctuation. Run wrath -F in the repository root. This will download and compile the latest version of Scala, as well as all of Punctuation's dependencies.

   If the build was successful, the compiled JAR files can be found in the .wrath/dist directory.

Contributing

Contributors to Punctuation are welcome and encouraged. New contributors may like to look for issues marked beginner.

We suggest that all contributors read the Contributing Guide to make the process of contributing to Punctuation easier.

Please do not contact project maintainers privately with questions unless there is a good reason to keep them private. While it can be tempting to repsond to such questions, private answers cannot be shared with a wider audience, and it can result in duplication of effort.

Author

Punctuation was designed and developed by Jon Pretty, and commercial support and training on all aspects of Scala 3 is available from Propensive OÜ.

Name

To punctuate is "to mark with points" (or more specifically, symbolic characters) and also, "to stress or single out as important", which describes Markdown in both the literal sense that punctuation characters are added to text, and in the figurative sense that this punctuates a document with stress and other styled emphasis.

In general, Soundness project names are always chosen with some rationale, however it is usually frivolous. Each name is chosen for more for its uniqueness and intrigue than its concision or catchiness, and there is no bias towards names with positive or "nice" meanings—since many of the libraries perform some quite unpleasant tasks.

Names should be English words, though many are obscure or archaic, and it should be noted how willingly English adopts foreign words. Names are generally of Greek or Latin origin, and have often arrived in English via a romance language.

Logo

The logo shows a downward arrow overlaid on a capital letter M, representing the "Mark-down" format.

License

Punctuation is copyright © 2024 Jon Pretty & Propensive OÜ, and is made available under the Apache 2.0 License.