src/test/run-pass/select-macro.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 // xfail-test - this isn't really a test.
  12
  13  {
  14
  15 // select!
  16 macro_rules! select_if (
  17
  18     {
  19         $index:expr,
  20         $count:expr
  21     } => {
  22         fail!()
  23     };
  24
  25     {
  26         $index:expr,
  27         $count:expr,
  28         $port:path => [
  29             $(type_this $message:path$(($(x $x: ident),+))dont_type_this*
  30               -> $next:ident => { $e:expr }),+
  31         ]
  32         $(, $ports:path => [
  33             $(type_this $messages:path$(($(x $xs: ident),+))dont_type_this*
  34               -> $nexts:ident => { $es:expr }),+
  35         ] )*
  36     } => {
  37         if $index == $count {
  38             match pipes::try_recv($port) {
  39               $(Some($message($($($x,)+)* next)) => {
  40                 let $next = next;
  41                 $e
  42               })+
  43               _ => fail!()
  44             }
  45         } else {
  46             select_if!(
  47                 $index,
  48                 $count + 1
  49                 $(, $ports => [
  50                     $(type_this $messages$(($(x $xs),+))dont_type_this*
  51                       -> $nexts => { $es }),+
  52                 ])*
  53             )
  54         }
  55     };
  56 )
  57
  58 macro_rules! select (
  59     {
  60         $( $port:path => {
  61             $($message:path$(($($x: ident),+))dont_type_this*
  62               -> $next:ident $e:expr),+
  63         } )+
  64     } => {
  65         let index = pipes::selecti([$(($port).header()),+]);
  66         select_if!(index, 0 $(, $port => [
  67             $(type_this $message$(($(x $x),+))dont_type_this* -> $next => { $e }),+
  68         ])+)
  69     }
  70 )
  71
  72 }