1
  2
  3
  4
  5
  6
  7
  8
  9
 10
 11
 12
 13
 14
 15
 16
 17
 18
 19
 20
 21
 22
 23
 24
 25
 26
 27
 28
 29
 30
 31
 32
 33
 34
 35
 36
 37
 38
 39
 40
 41
 42
 43
 44
 45
 46
 47
 48
 49
 50
 51
 52
 53
 54
 55
 56
 57
 58
 59
 60
 61
 62
 63
 64
 65
 66
 67
 68
 69
 70
 71
 72
 73
 74
 75
 76
 77
 78
 79
 80
 81
 82
 83
 84
 85
 86
 87
 88
 89
 90
 91
 92
 93
 94
 95
 96
 97
 98
 99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283

// 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.
//!
//! ```html
//! @(name: &str, value: &u32)
//!
//! <html>
//!   <head><title>@name</title></head>
//!   <body>
//!     <p>The value of @name is @value.</p>
//!   <body>
//! </html>
//! ```
//!
//! As seen above, string slices and integers can easily be outputed
//! in the template body, using `@name` where `name` is a parameter of
//! the template.
//! Actually, more complex expressions can be outputed in the same
//! way, as long as the resulting value implements [`ToHtml`].
//! Rust types that implements [`Display`] automatically implements
//! [`ToHtml`] in such a way that contents are safely escaped for
//! html.
//!
//! ```html
//! @use any::rust::Type;
//!
//! @(name: &str, items: &[Type])
//!
//! <html>
//!   <head><title>@name</title></head>
//!   <body>
//!     @if items.is_empty() {
//!       <p>There are no items.</p>
//!     } else {
//!       <p>There are @items.len() items.</p>
//!       <ul>
//!       @for item in items {
//!         <li>@item</li>
//!       }
//!       </ul>
//!   <body>
//! </html>
//! ```
//!
//! The curly brackets, `{` and `}`, is used for blocks (see Loops,
//! Conditionals, and Calling other templates below).

//! To use verbatim curly brackets in the template body, they must be
//! escaped as `@{` and `@}`, the same goes for the `@` sign, that
//! precedes expressions and special blocks; verbtim `@` signs must be
//! escaped as `@@`.
//!
//! [`ToHtml`]: ../templates/trait.ToHtml.html
//! [`Display`]: https://doc.rust-lang.org/std/fmt/trait.Display.html
#![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>
    //! ```
    //! If `a` is 2, this exapands to:
    //! ```text
    //! <p>The sum 2+3 is 5.</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>
    //! ```
    //!
    //! An expression ends when parenthesis and brackets are matched
    //! and it is followed by something not allowed in an expression.
    //! This includes whitespace and e.g. the `<` and `@` characters.
    //! If an expression starts with an open parenthesis, the
    //! expression ends when that parentheis is closed.
    //! That is usefull if an expression is to be emmediatley followed
    //! by something that would be allowed in an expression.
    //!
    //! ```text
    //! <p>@arg</p>
    //! <p>@arg.</p>
    //! <p>@arg.@arg</p>
    //! <p>@arg.len()</p>
    //! <p>@(arg).len()</p>
    //! <p>@((2_i8 - 3).abs())</p>@* Note extra parens needed here *@
    //! ```
    //! With `arg = "name"`, the above renders as:
    //! ```text
    //! <p>name</p>
    //! <p>name.</p>
    //! <p>name.name</p>
    //! <p>4</p>
    //! <p>name.len()</p>
    //! <p>1</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;
    //!
    //! @()
    //!
    //! <html>
    //!   @:header_html("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_html;
    //!
    //! @()
    //!
    //! @:base_page_html("Example", {
    //!     <p>page content ...</p>
    //! })
    //! ```
}