Fix handling of SIGINT

Keep track of a new atomic variable: at_prompt, which is set to true
just before blocking on io::stdin.read_line, and set to false just
calling Poem::read. Additionally, for background tasks, there is a new
ps macro called btask, which changes the process group of commands that
are forked into the background, so that they don't receive SIGINT from
the keyboard.

1 files changed, 33 insertions, 0 deletions

diff --git a/src/recite/ps.rs b/src/recite/ps.rs
index d0e2435..bb18b3f 100644
--- a/src/recite/ps.rs
+++ b/src/recite/ps.rs
@@ -60,3 +60,36 @@ macro_rules! ctask {
         }
     };
 }
+
+#[macro_export]
+/// Fork into a background process from a Verse
+///
+/// Figures out whether or not the given Verse is a couplet. If it is, fork
+/// into a backgournd process, and pipe the contents of out `out` into STDIN.
+/// If not, then simply fork into the background process.
+///
+/// # Arguments
+/// * `$verse: &Verse` - The verse to fork into
+/// * `$out: &mut String` - If the $verse is a couplet, the contents of STDOUT from the last verse
+macro_rules! btask {
+    ($verse:expr, $out:expr) => {
+        if $verse.couplet {
+            let mut child = Command::new($verse.verb())
+                .args($verse.clause())
+                .stdin(Stdio::piped())
+                .process_group(0)
+                .spawn()?;
+
+            let stdin = child.stdin.as_mut().ok_or(io::ErrorKind::BrokenPipe)?;
+            stdin.write_all(&$out.as_bytes())?;
+            $out.clear();
+
+            child
+        } else {
+            Command::new($verse.verb())
+                .args($verse.clause())
+                .process_group(0)
+                .spawn()?
+        }
+    };
+}