Add more code comments.

[dead/htsn.git] / src / Main.hs

diff --git a/src/Main.hs b/src/Main.hs
index 374981248fd9bf2b17905175949914d89cea70e4..1b7458fe880c83463038abbc2de73be16f3d09ff 100644 (file)
--- a/src/Main.hs
+++ b/src/Main.hs
@@ -44,6 +44,9 @@ import TSN.FeedHosts (FeedHosts(..))
 import TSN.Xml (parse_xmlfid, xml_prologue)
 
 
+-- | Receive a single line of text from a Handle, echoing it to stdout
+--   in the process.
+--
 recv_line :: Handle -> IO String
 recv_line h = do
   line <- hGetLine h
@@ -51,6 +54,13 @@ recv_line h = do
   return line
 
 
+-- | Takes a Configuration, and an XML document (as a String). The XML
+--   document is written to the output directory, as specified by the
+--   Configuration.
+--
+--   This can fail, but we don't purposefully throw any exceptions. If
+--   something goes wrong, we would rather log it and keep going.
+--
 save_document :: Configuration -> String -> IO ()
 save_document cfg doc =
   case maybe_path of
@@ -67,8 +77,11 @@ save_document cfg doc =
     filename = fmap (++ ".xml") xmlfid
     maybe_path = fmap ((output_directory cfg) </>) filename
 
+
 -- | Loop forever, writing the buffer to file whenever a new XML
---   prologue is seen.
+--   prologue is seen. This is the low-level "loop forever" function
+--   that we stay in as long as we are connected to one feed.
+--
 loop :: Configuration -> Handle -> [String] -> IO ()
 loop !cfg !h !buffer = do
   line <- recv_line h
@@ -83,7 +96,8 @@ loop !cfg !h !buffer = do
     save_document cfg document
     loop cfg h [line] -- empty the buffer before looping again
   else
-    loop cfg h (line : buffer) -- append line to the head of the buffer and loop
+    -- append line to the head of the buffer and loop
+    loop cfg h (line : buffer)
 
 
 log_in :: Configuration -> Handle -> IO ()
@@ -152,12 +166,14 @@ connect_and_loop cfg host = do
 
 -- | A wrapper around threadDelay which takes seconds instead of
 --   microseconds as its argument.
+--
 thread_sleep :: Int -> IO ()
 thread_sleep seconds = do
   let microseconds = seconds * (10 ^ (6 :: Int))
   threadDelay microseconds
 
 
+-- | The entry point of the program.
 main :: IO ()
 main = do
   rc_cfg <- OC.from_rc
@@ -187,12 +203,21 @@ main = do
   -- set in either the config file or on the command-line.
   let cfg = (def :: Configuration) `merge_optional` opt_config
 
+  -- This may be superstition (and I believe stderr is unbuffered),
+  -- but it can't hurt.
   hSetBuffering stderr NoBuffering
   hSetBuffering stdout NoBuffering
 
+  -- Begin connecting to our feed hosts, starting with the first one.
   round_robin cfg 0
 
   where
+    -- | This is the top-level "loop forever" function. If an
+    --   exception is thrown, it will propagate up to this point, where
+    --   it will be logged and ignored in style.
+    --
+    --   Afterwards, we recurse (call ourself) again to loop more forevers.
+    --
     round_robin :: Configuration -> Int -> IO ()
     round_robin cfg feed_host_idx = do
       let hosts = get_feed_hosts $ feed_hosts cfg