Improved shell example

examples/shell/shell.q

@@ -2,29 +2,35 @@ import io
 import mem
 import sys
 
+const idtype {
+	pid 1
+}
+
+const state {
+	exited 0x4
+}
+
 main() {
 	length := 256
 	command := mem.alloc(length)
-	argv := mem.alloc(1)
+	siginfo := mem.alloc(128)
-	envp := mem.alloc(1)
-	info := mem.alloc(24)
 
 	loop {
-		io.out("$ ")
+		io.out("λ ")
 		n := io.in(command)
 
 		if n <= 0 {
 			return
 		}
 
-		command[n-1] = '\0'
+		command[n-1] = 0
 		pid := sys.fork()
 
 		if pid == 0 {
-			sys.execve(command, argv, envp)
+			sys.execve(command, 0, 0)
 			return
 		}
 
-		sys.waitid(0, pid, info, 4)
+		sys.waitid(idtype.pid, pid, siginfo, state.exited)
 	}
 }