src/test/run-pass/html-literals.rs

   1 // Copyright 2012 The Rust Project Developers. See the COPYRIGHT
   2 // file at the top-level directory of this distribution and at
   3 // http://rust-lang.org/COPYRIGHT.
   4 //
   5 // Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
   6 // http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
   7 // <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
   8 // option. This file may not be copied, modified, or distributed
   9 // except according to those terms.
  10
  11 // A test of the macro system. Can we do HTML literals?
  12
  13 // ignore-test FIXME #20673
  14
  15 /*
  16
  17 This is an HTML parser written as a macro. It's all CPS, and we have
  18 to carry around a bunch of state. The arguments to macros all look like this:
  19
  20 { tag_stack* # expr* # tokens }
  21
  22 The stack keeps track of where we are in the tree. The expr is a list
  23 of children of the current node. The tokens are everything that's
  24 left.
  25
  26 */
  27 use HTMLFragment::{tag, text};
  28
  29 macro_rules! html {
  30     ( $($body:tt)* ) => (
  31         parse_node!( []; []; $($body)* )
  32     )
  33 }
  34
  35 macro_rules! parse_node {
  36     (
  37         [:$head:ident ($(:$head_nodes:expr),*)
  38          $(:$tags:ident ($(:$tag_nodes:expr),*))*];
  39         [$(:$nodes:expr),*];
  40         </$tag:ident> $($rest:tt)*
  41     ) => (
  42         parse_node!(
  43             [$(: $tags ($(:$tag_nodes),*))*];
  44             [$(:$head_nodes,)* :tag(stringify!($head).to_string(),
  45                                     vec!($($nodes),*))];
  46             $($rest)*
  47         )
  48     );
  49
  50     (
  51         [$(:$tags:ident ($(:$tag_nodes:expr),*) )*];
  52         [$(:$nodes:expr),*];
  53         <$tag:ident> $($rest:tt)*
  54     ) => (
  55         parse_node!(
  56             [:$tag ($(:$nodes)*) $(: $tags ($(:$tag_nodes),*) )*];
  57             [];
  58             $($rest)*
  59         )
  60     );
  61
  62     (
  63         [$(:$tags:ident ($(:$tag_nodes:expr),*) )*];
  64         [$(:$nodes:expr),*];
  65         . $($rest:tt)*
  66     ) => (
  67         parse_node!(
  68             [$(: $tags ($(:$tag_nodes),*))*];
  69             [$(:$nodes,)* :text(".".to_string())];
  70             $($rest)*
  71         )
  72     );
  73
  74     (
  75         [$(:$tags:ident ($(:$tag_nodes:expr),*) )*];
  76         [$(:$nodes:expr),*];
  77         $word:ident $($rest:tt)*
  78     ) => (
  79         parse_node!(
  80             [$(: $tags ($(:$tag_nodes),*))*];
  81             [$(:$nodes,)* :text(stringify!($word).to_string())];
  82             $($rest)*
  83         )
  84     );
  85
  86     ( []; [:$e:expr]; ) => ( $e );
  87 }
  88
  89 pub fn main() {
  90     let _page = html! (
  91         <html>
  92             <head><title>This is the title.</title></head>
  93             <body>
  94             <p>This is some text</p>
  95             </body>
  96         </html>
  97     );
  98 }
  99
 100 enum HTMLFragment {
 101     tag(String, Vec<HTMLFragment> ),
 102     text(String),
 103 }