proc do a1 getAtom str1 res1 sendSomewhere a1 if res1 then returnA a1

proc () -> do
    a1 <- getAtom -< str1
    res1 <- sendSomewhere -< a1
    if res1
    then returnA -< a1
    else do
        a2 <- getAtom -< str2
        res2 <- sendElsewhere -< a2
        returnA -< res2