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// This module is only a chapter of the documentation.
//! This module describes the template syntax used by ructe.
//!
//! The syntax is inspired by
//! [Twirl](https://github.com/playframework/twirl), the Scala-based
//! template engine in
//! [Play framework](https://www.playframework.com/),
//! but of course with rust types expressions instead of scala.
//!
//! A template consists of three basic parts:
//! First a preamble of `use` statements, each prepended by an @ sign.
//! Secondly a declaration of the parameters the template takes.
//! And third, the template body.
//!
//! ```text
//! @use any::rust::Type;
//!
//! @(name: &str, items: &[Type])
//!
//! <html>
//! ...
//! </html>
//! ```
//!
//! The curly brackets, `{` and `}`, is used for blocks (see Loops,
//! Conditionals, and Calling other templates below).
//! To use them in the template body, they must be escaped as `@{` and
//! `@}`.
#![allow(non_snake_case)]
pub mod a_Value_expressions {
//! A value expression can be as simple as `@name` to get the value of
//! a parameter, but more complicated expressions, including function
//! calls, are also allowed.
//!
//! # Value expressions
//!
//! A parameter can be used in an expression preceded by an @ sign.
//!
//! ```text
//! <h1>@name</h1>
//! ```
//!
//! If a parameter is a struct or a trait object, its fields or methods can
//! be used, and if it is a callable, it can be called.
//!
//! ```text
//! <p>The user @user.name has email @user.get_email().</p>
//! <p>A function result is @function(with, three, arguments).</p>
//! ```
//!
//! Standard function and macros can also be used, e.g. for specific
//! formatting needs:
//!
//! ```text
//! <p>The value is @format!("{:.1}", float_value).</p>
//! ```
//!
//! If more complex expressions are needed, they can be put in
//! parenthesis.
//!
//! ```text
//! <p>The sum @a+3 is @(a+3).</p>
//! ```
//!
//! Anything is allowed in parenthesis, as long as parenthesis,
//! brackets and string quotes are balanced.
//! Note that this also applies to the parenthesis of a function
//! call or the brackets of an index, so complex things like the
//! following are allowed:
//!
//! ```text
//! <p>Index: @myvec[t.map(|s| s.length()).unwrap_or(0)].</p>
//! <p>Argument: @call(a + 3, |t| t.something()).</p>
//! ```
}
pub mod b_Loops {
//! A ructe `@for` loop works just as a rust `for` loop,
//! iterating over anything that implements `std::iter::IntoIterator`,
//! such as a `Vec` or a slice.
//!
//! # Loops
//!
//! Rust-like loops are supported like this:
//!
//! ```text
//! <ul>@for item in items {
//! <li>@item</li>
//! }</ul>
//! ```
//!
//! Note that the thing to loop over (items, in the example) is a rust
//! expression, while the contents of the block is template code.
//!
//! If items is a slice of tuples (or really, anything that is
//! iterable yielding tuples), it is possible to deconstruct the
//! tuples into separate values directly:
//!
//! ```text
//! @for (n, item) in items.iter().enumerate() {
//! <p>@n: @item</p>
//! }
//! ```
//!
//! It is also possible to loop over a literal array (which may be
//! an array of tuples), as long as you do it by reference:
//!
//! ```text
//! @for &(name, age) in &[("Rasmus", 44), ("Mike", 36)] {
//! <p>@name is @age years old.</p>
//! }
//! ```
}
pub mod c_Conditionals {
//! Both `@if` statements with boolean expressions and match-like
//! guard `@if let` statements are supported.
//!
//! # Conditionals
//!
//! Rust-like conditionals are supported in a style similar to the loops:
//!
//! ```text
//! @if items.is_empty() {
//! <p>There are no items.</p>
//! }
//! ```
//!
//! Pattern matching let expressions are also supported, as well as an
//! optional else part.
//!
//! ```text
//! @if let Some(foo) = foo {
//! <p>Foo is @foo.</p>
//! } else {
//! <p>There is no foo.</p>
//! }
//! ```
//!
//! General rust `match` statements are _not_ supported in ructe
//! (at least not yet).
}
pub mod d_Calling_other_templates {
//! The ability to call other templates for from a template makes
//! both "tag libraries" and "base templates" possible with the
//! same syntax.
//!
//! # Calling other templates
//!
//! While rust methods can be called as a simple expression, there is a
//! special syntax for calling other templates:
//! `@:template_name(template_arguments)`.
//! Also, before calling a template, it has to be imported by a `use`
//! statement.
//! Templates are declared in a `templates` module.
//!
//! So, given something like this in `header.rs.html`:
//!
//! ```text
//! @(title: &str)
//!
//! <head>
//! <title>@title</title>
//! <link rel="stylesheet" href="/my/style.css" type="text/css">
//! </head>
//! ```
//!
//! It can be used like this:
//!
//! ```text
//! @use super::header;
//!
//! @()
//!
//! <html>
//! @:header("Example")
//! <body>
//! <h1>Example</h1>
//! <p>page content ...</p>
//! </body>
//! </html>
//! ```
//!
//! It is also possible to send template blocks as parameters to templates.
//! A structure similar to the above can be created by having something like
//! this in `base_page.rs.html`:
//!
//! ```text
//! @(title: &str, body: Content)
//!
//! <html>
//! <head>
//! <title>@title</title>
//! <link rel="stylesheet" href="/my/style.css" type="text/css">
//! </head>
//! <body>
//! <h1>@title</h1>
//! @:body()
//! </body>
//! </html>
//! ```
//!
//! And use it like this:
//!
//! ```text
//! @use super::base_page;
//!
//! @()
//!
//! @:base_page("Example", {
//! <p>page content ...</p>
//! })
//! ```
}