Working on a macro for selecting from many pipes.

Author: eholk

src/test/run-pass/pipe-select-macro.rs

@@ -0,0 +1,112 @@
+// xfail-test
+
+// Protocols
+proto! foo {
+    foo:recv {
+        do_foo -> foo
+    }
+}
+
+proto! bar {
+    bar:recv {
+        do_bar(int) -> barbar,
+        do_baz(bool) -> bazbar,
+    }
+
+    barbar:send {
+        rebarbar -> bar,
+    }
+
+    bazbar:send {
+        rebazbar -> bar
+    }
+}
+
+
+// select!
+macro_rules! select_if {
+    {
+        $index:expr,
+        $count:expr,
+        $port:path => [
+            $($message:path$(($($x: ident),+))dont_type_this*
+              -> $next:ident $e:expr),+
+        ],
+        $( $ports:path => [
+            $($messages:path$(($($xs: ident),+))dont_type_this*
+              -> $nexts:ident $es:expr),+
+        ], )*
+    } => {
+        log_syntax!{select_if1};
+        if $index == $count {
+            alt move pipes::try_recv($port) {
+              $(some($message($($($x,)+)* next)) => {
+                // FIXME (#2329) we really want move out of enum here.
+                let $next = unsafe { let x <- *ptr::addr_of(next); x };
+                $e
+              })+
+              _ => fail
+            }
+        } else {
+            select_if!{
+                $index,
+                $count + 1,
+                $( $ports => [
+                    $($messages$(($($xs),+))dont_type_this*
+                      -> $nexts $es),+
+                ], )*
+            }
+        }
+    };
+
+    {
+        $index:expr,
+        $count:expr,
+    } => {
+        log_syntax!{select_if2};
+        fail
+    }
+}
+
+macro_rules! select {
+    {
+        $( $port:path => {
+            $($message:path$(($($x: ident),+))dont_type_this*
+              -> $next:ident $e:expr),+
+        } )+
+    } => {
+        let index = pipes::selecti([$(($port).header()),+]/_);
+        log_syntax!{select};
+        log_syntax!{
+        select_if!{index, 0, $( $port => [
+            $($message$(($($x),+))dont_type_this* -> $next $e),+
+        ], )+}
+        };
+        select_if!{index, 0, $( $port => [
+            $($message$(($($x),+))dont_type_this* -> $next $e),+
+        ], )+}
+    }
+}
+
+// Code
+fn test(+foo: foo::client::foo, +bar: bar::client::bar) {
+    select! {
+        foo => {
+            foo::do_foo -> _next {
+            }
+        }
+
+        bar => {
+            bar::do_bar(x) -> _next {
+                //debug!("%?", x)
+            },
+
+            do_baz(b) -> _next {
+                //if b { debug!("true") } else { debug!("false") }
+            }
+        }
+    }
+}
+
+fn main() {
+}