skhtml/typed-html/src/lib.rs

228 lines
8.4 KiB
Rust

//! This crate provides the `html!` macro for building HTML documents inside your
//! Rust code using roughly [JSX] compatible syntax.
//!
//! # Quick Preview
//!
//! ```
//! # #![recursion_limit = "128"]
//! # use typed_html::html;
//! # use typed_html::dom::{DOMTree, VNode};
//! # use typed_html::types::Metadata;
//! # fn main() {
//! let mut doc: DOMTree<String> = html!(
//! <html>
//! <head>
//! <title>"Hello Kitty"</title>
//! <meta name=Metadata::Author content="Not Sanrio Co., Ltd"/>
//! </head>
//! <body>
//! <h1>"Hello Kitty"</h1>
//! <p class="official">
//! "She is not a cat. She is a human girl."
//! </p>
//! { (0..3).map(|_| html!(
//! <p class="emphasis">
//! "Her name is Kitty White."
//! </p>
//! )) }
//! <p class="citation-needed">
//! "We still don't know how she eats."
//! </p>
//! </body>
//! </html>
//! );
//! let doc_str = doc.to_string();
//! # }
//! ```
//!
//! # Syntax
//!
//! This macro largely follows [JSX] syntax, but with some differences:
//!
//! * Text nodes must be quoted, because there's only so much Rust's tokeniser can
//! handle outside string literals. So, instead of `<p>Hello</p>`, you need to
//! write `<p>"Hello"</p>`. (The parser will throw an error asking you to do this
//! if you forget.)
//! * Element attributes will accept simple Rust expressions, but the parser has
//! its limits, as it's not a full Rust parser. You can use literals,
//! variables, dotted properties, type constructors and single function or
//! method calls. If you use something the parser isn't currently capable of
//! handling, it will complain. You can put braces or parentheses around the
//! expression if the parser doesn't understand
//! it. You can use any Rust code inside a brace or parenthesis block.
//!
//! # Valid HTML5
//!
//! The macro will only accept valid HTML5 tags, with no tags or attributes marked
//! experimental or obsolete. If it won't accept something you want it to accept, we
//! can discuss it over a pull request (experimental tags and attributes, in
//! particular, are mostly omitted just for brevity, and you're welcome to implement
//! them).
//!
//! The structure validation is simplistic by necessity, as it defers to the type
//! system: a few elements will have one or more required children, and any element
//! which accepts children will have a restriction on the type of the children,
//! usually a broad group as defined by the HTML spec. Many elements have
//! restrictions on children of children, or require a particular ordering of
//! optional elements, which isn't currently validated.
//!
//! # Attribute Values
//!
//! Brace blocks in the attribute value position should return the expected type for
//! the attribute. The type checker will complain if you return an unsupported type.
//! You can also use literals or a few simple Rust expressions as attribute values
//! (see the Syntax section above).
//!
//! The `html!` macro will add an [`.into()`][Into::into] call to the value
//! expression, so that you can use any type that has an [`Into<A>`][Into] trait
//! defined for the actual attribute type `A`.
//!
//! As a special case, if you use a string literal, the macro will instead use the
//! [`FromStr<A>`][FromStr] trait to try and parse the string literal into the
//! expected type. This is extremely useful for eg. CSS classes, letting you type
//! `class="css-class-1 css-class-2"` instead of going to the trouble of
//! constructing a [`SpacedSet<Class>`][SpacedSet]. The big caveat for this:
//! currently, the macro is not able to validate the string at compile time, and the
//! conversion will panic at runtime if the string is invalid.
//!
//! ## Example
//!
//! ```
//! # use typed_html::html;
//! # use typed_html::dom::DOMTree;
//! # use typed_html::types::{Class, SpacedSet};
//! # fn main() {
//! let classList: SpacedSet<Class> = ["foo", "bar", "baz"].into();
//! # let doc: DOMTree<String> =
//! html!(
//! <div>
//! <div class="foo bar baz" /> // parses a string literal
//! <div class=["foo", "bar", "baz"] /> // uses From<[&str, &str, &str]>
//! <div class=classList /> // uses a variable in scope
//! <div class={ // evaluates a code block
//! SpacedSet::from(["foo", "bar", "baz"])
//! } />
//! </div>
//! )
//! # ;}
//! ```
//!
//! # Generated Nodes
//!
//! Brace blocks in the child node position are expected to return an
//! [`IntoIterator`][IntoIterator] of [`DOMTree`][DOMTree]s. You can return single
//! elements or text nodes, as they both implement `IntoIterator` for themselves.
//! The macro will consume this iterator at runtime and insert the generated nodes
//! as children in the expected position.
//!
//! ## Example
//!
//! ```
//! # use typed_html::{html, text};
//! # use typed_html::dom::DOMTree;
//! # fn main() {
//! # let doc: DOMTree<String> =
//! html!(
//! <ul>
//! { (1..=5).map(|i| html!(
//! <li>{ text!("{}", i) }</li>
//! )) }
//! </ul>
//! )
//! # ;}
//! ```
//!
//! # Rendering
//!
//! You have two options for actually producing something useful from the DOM tree
//! that comes out of the macro.
//!
//! ## Render to a string
//!
//! The DOM tree data structure implements [`Display`][Display], so you can call
//! [`to_string()`][to_string] on it to render it to a [`String`][String]. If you
//! plan to do this, the type of the tree should be [`DOMTree<String>`][DOMTree] to
//! ensure you're not using any event handlers that can't be printed.
//!
//! ```
//! # use typed_html::html;
//! # use typed_html::dom::DOMTree;
//! # fn main() {
//! let doc: DOMTree<String> = html!(
//! <p>"Hello Kitty"</p>
//! );
//! let doc_str = doc.to_string();
//! assert_eq!("<p>Hello Kitty</p>", doc_str);
//! # }
//! ```
//!
//! ## Render to a virtual DOM
//!
//! The DOM tree structure also implements a method called `vnode()`, which renders
//! the tree to a tree of [`VNode`][VNode]s, which is a mirror of the generated tree
//! with every attribute value rendered into `String`s. You can walk this virtual
//! DOM tree and use it to build an actual DOM tree with `stdweb` or pass it on to
//! your favourite virtual DOM system.
//!
//! # Licence
//!
//! Copyright 2018 Bodil Stokke
//!
//! This software is subject to the terms of the Mozilla Public License, v. 2.0. If
//! a copy of the MPL was not distributed with this file, You can obtain one at
//! <http://mozilla.org/MPL/2.0/>.
//!
//! # Code of Conduct
//!
//! Please note that this project is released with a [Contributor Code of
//! Conduct][coc]. By participating in this project you agree to abide by its terms.
//!
//! [coc]: https://www.contributor-covenant.org/version/1/4/code-of-conduct
//! [JSX]: https://reactjs.org/docs/introducing-jsx.html
//! [Display]: https://doc.rust-lang.org/std/fmt/trait.Display.html
//! [String]: https://doc.rust-lang.org/std/string/struct.String.html
//! [to_string]: https://doc.rust-lang.org/std/string/trait.ToString.html#tymethod.to_string
//! [Node]: dom/trait.Node.html
//! [VNode]: dom/enum.VNode.html
//! [FromStr]: https://doc.rust-lang.org/std/str/trait.FromStr.html
//! [SpacedSet]: types/struct.SpacedSet.html
//! [IntoIterator]: https://doc.rust-lang.org/std/iter/trait.IntoIterator.html
//! [Into]: https://doc.rust-lang.org/std/convert/trait.Into.html
//! [Into::into]: https://doc.rust-lang.org/std/convert/trait.Into.html#method.into
//! [DOMTree]: dom/type.DOMTree.html
pub extern crate htmlescape;
use proc_macro_hack::proc_macro_hack;
use std::fmt::Display;
#[proc_macro_hack(support_nested)]
pub use typed_html_macros::html;
#[cfg(feature = "dodrio_macro")]
#[proc_macro_hack(support_nested)]
pub use typed_html_macros::dodrio;
pub mod dom;
pub mod elements;
pub mod events;
pub mod output;
pub mod types;
/// Marker trait for outputs
pub trait OutputType {
/// The type that contains events for this output.
type Events: Default + Display;
/// The type of event targets for this output.
type EventTarget;
/// The type that's returned from attaching an event listener to a target.
type EventListenerHandle;
}
/// String output
impl OutputType for String {
type Events = events::Events<String>;
type EventTarget = ();
type EventListenerHandle = ();
}