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https://github.com/propensive/honeycomb
A lightweight and typesafe DSL for embedding HTML in Scala code
https://github.com/propensive/honeycomb
dsl html html5 scala typesafe
Last synced: 10 days ago
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A lightweight and typesafe DSL for embedding HTML in Scala code
- Host: GitHub
- URL: https://github.com/propensive/honeycomb
- Owner: propensive
- Created: 2018-05-07T23:35:51.000Z (over 6 years ago)
- Default Branch: main
- Last Pushed: 2024-10-20T16:13:36.000Z (17 days ago)
- Last Synced: 2024-10-20T19:09:49.435Z (17 days ago)
- Topics: dsl, html, html5, scala, typesafe
- Language: Scala
- Homepage: https://propensive.com/honeycomb/
- Size: 2.1 MB
- Stars: 6
- Watchers: 4
- Forks: 0
- Open Issues: 8
-
Metadata Files:
- Readme: .github/readme.md
- Contributing: .github/contributing.md
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README
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# Honeycomb
__Perfectly-nested HTML__
_Honeycomb_ provides a typesafe representation of HTML5 which goes as far as possible in the scope of
Scala's type system to ensure that the HTML specification is correctly modeled, for example by
enforcing nesting rules between different tags.
## Features
- simple method-application style for constructing HTML nodes
- nodes and sequences of nodes may be embedded and mixed inside HTML nodes
- the type of a node defines the valid types of its child nodes, enforcing the HTML5 specification through the type system
- values of other types may be embedded in HTML, if an appropriate typeclass instance exists
- a simple named-parameter style is provided for HTML attributes
- HTML attributes are strongly-typed, and the types accepted by each are defined by typeclasses
## Availability
## Getting Started
### Constructing HTML nodes
Simple HTML nodes can be constructed by applying other nodes (or strings) to `Tag` instances, for example:
```scala
val table = Table(
Tbody(
Tr(Th("Name"), Th("Age")),
Tr(Td("Andrew"), Td("18"))
)
)
```
Note that the two `Tr` nodes are separated by a comma (`,`) since they are applied as repeated arguments.
This will produce HTML nodes representing the HTML code:
```html
Name
Age
Andrew
18
```
The example shows,
- a `Tbody` node nested inside a `Table`
- `Tr` nodes nested inside a `Tbody`
- `Th` and `Td` nodes nested inside `Tr`s
These are all permitted in HTML 5, so they are permitted in Honeycomb. But while it would be
possible to write the HTML,
```html
Name
```
and a web browser may even render it in some way, the code `Tr(Tbody(Td("Name")))` is not valid,
and will not compile, because a `Td` cannot be a direct child of a `Tbody` node, and a `Tbody` node
may not be nested inide a `Tr` node.
`Tag` objects for every HTML node exist, and rules about which nodes are permitted as children of
each one are encoded in their types. This makes it possible to write HTML code which conforms to the
HTML 5 specification.
`Tag`s have the same name as their HTML counterparts, written with a capital letter.
There are some limitations to this in cases where HTML's rules are defined in terms of more than a
simple nesting relationship, but work is ongoing to encode as many constraints as possible. In all
cases where HTML 5 rules are not fully implemented, Honeycomb is more permissive.
### Attributes
HTML nodes may also have attributes. These can be applied to an additional parameter block _before_
the child nodes, in the style of named parameters, for example,
```scala
Td(colspan = 2, id = "cell_1")("Data")
```
Only attributes that are valid for a particular `Tag` type may be used on that tag. Also note that the
attribute values have different types: `colspan` takes an `Int` and `id` takes a `String`. By default,
attributes are configured to accept the most suitable types for describing their values, without
being overly permissive.
Many such types are not defined in Honeycomb, since their representation is best handled by other
libraries. Other libraries may nevertheless make their types usable by Honeycomb without adding a
hard dependency on Honeycomb. This facility is provided through typeclasses defined in
[Anticipation](https://github.com/propensive/anticipation), which becomes a necessary dependency
of both libraries, but is tiny, so does not impose any significant burden.
For example, if including [Gesticulate](https://github.com/propensive/gesticulate/) to represent
Media types, it becomes possible use a Gesticulate media type for an attribute such as `type` on
a `Style` tag, like so,
```scala
import gesticulate.*
val styles = Style(htype = media"text/css")(css)
```
without any additional imports.
A contextual instance of `anticipation.HtmlAttribute` is all that is required to make this possible.
## Status
Honeycomb 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.
Honeycomb is designed to be _small_. Its entire source code currently consists
of 733 lines of code.
## Building
Honeycomb 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 Honeycomb?".
1. *Copy the sources into your own project*
Read the `fury` file in the repository root to understand Honeycomb'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](https://github.com/propensive/wrath/)*
Wrath is a bootstrapping script for building Honeycomb 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`](https://github.com/propensive/wrath/releases/latest), 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 `honeycomb`.
Run `wrath -F` in the repository root. This will download and compile the
latest version of Scala, as well as all of Honeycomb's dependencies.
If the build was successful, the compiled JAR files can be found in the
`.wrath/dist` directory.
## Contributing
Contributors to Honeycomb are welcome and encouraged. New contributors may like
to look for issues marked
[beginner](https://github.com/propensive/honeycomb/labels/beginner).
We suggest that all contributors read the [Contributing
Guide](/contributing.md) to make the process of contributing to Honeycomb
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
Honeycomb was designed and developed by Jon Pretty, and commercial support and
training on all aspects of Scala 3 is available from [Propensive
OÜ](https://propensive.com/).
## Name
Honeycomb is named after the hexagonal prismic cells in a bees' nest, where they store their honey and their larvæ; the most innovative feature of Honeycomb is its provision of safe nesting of HTML nodes.
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 part of the abdomen of a bee, the insect which makes honeycomb.
## License
Honeycomb is copyright © 2024 Jon Pretty & Propensive OÜ, and
is made available under the [Apache 2.0 License](/license.md).