X-Git-Url: http://gitweb.michael.orlitzky.com/?a=blobdiff_plain;f=src%2FXml.hs;h=866ac4647fc258326cf8369ad5783f0a1ee375a6;hb=2069d0a786bf2c418f27574f5384eae39527d03f;hp=95eddc0e51f949acbb287003dfb98c22ff244cb4;hpb=ce9fabd584f2e8844b8b1ede9b29bb573e2033f7;p=dead%2Fhtsn-import.git

diff --git a/src/Xml.hs b/src/Xml.hs
index 95eddc0..866ac46 100644
--- a/src/Xml.hs
+++ b/src/Xml.hs
@@ -10,6 +10,7 @@ module Xml (
   unpickleable )
 where
 
+-- System imports.
 import Control.Exception ( SomeException(..), catch )
 import Text.XML.HXT.Core (
   (>>>),
@@ -17,7 +18,7 @@ import Text.XML.HXT.Core (
   PU,
   SysConfigList,
   XmlPickler(..),
-  hasName,
+  isElem,
   readDocument,
   runX,
   withRemoveWS,
@@ -26,40 +27,43 @@ import Text.XML.HXT.Core (
   yes )
 
 
--- | A typeclass for XML types that can be converted into an associated
---   database type. The story behind this is long, but basically, we need
---   to different types for each XML thingie we're going to import: a
---   database type and an XML type. Both Groundhog and HXT are very
---   particular about the types that they can use, and there's no way
---   to reuse e.g. a type that HXT can pickle in Groundhog. So this
---   typeclass gives us a way to get the database type from the XML
---   type that we have to define for HXT.
+-- | A typeclass for XML types that can be converted into an
+--   associated database type. The story behind this is long, but
+--   basically, we need to different types most XML thingies we're
+--   going to import: a database type and an XML type.
+--
+--   Both Groundhog and HXT are very particular about the types that
+--   they can use, and there's no way to reuse e.g. a type that HXT
+--   can pickle in Groundhog. This typeclass gives us a standard way
+--   to get the database type from the XML type that we have to define
+--   for HXT.
 --
 class FromXml a where
-  -- | Each instance a must declare its associated database type (Db a)
+  -- | Each instance @a@ must declare its associated database type @Db a@.
   type Db a :: *
 
-  -- | And provide a function for getting a (Db a) out of an "a".
+  -- | And provide a function for getting a @Db a@ out of an @a@.
   from_xml :: a -> Db a
 
 
--- | Represents the DTD filename ("SYSTEM") part of the DOCTYPE
+-- | Represents the DTD filename (\"SYSTEM\") part of the DOCTYPE
 --   definition.
 newtype DtdName = DtdName String
 
 -- | A list of options passed to 'readDocument' when we parse an XML
 --   document. All cosmetic whitespace should be removed, otherwise we
---   have to parse it in each pickler.
+--   would have to parse whitespace in each (un)pickler.
 --
 parse_opts :: SysConfigList
 parse_opts = [ withRemoveWS yes ]
 
 
--- | Given a root element name and a file path, return both the
---   original unpickled root "object" and the one that was constructed
---   by pickled and unpickling the original. This is used in a number
---   of XML tests which pickle/unpickle and then make sure that the
---   output is the same as the input.
+-- | Given an @unpickler@ and a @filepath@, attempt to unpickle the
+--   root element of @filepath@ using @unpickler@ and return both the
+--   original unpickled object and one constructed by pickling and
+--   unpickling that original. This is used in a number of XML tests
+--   which pickle/unpickle and then make sure that the output is the
+--   same as the input.
 --
 --   We return the object instead of an XmlTree (which would save us
 --   an unpickle call) because otherwise the type of @a@ in the call
@@ -71,27 +75,26 @@ parse_opts = [ withRemoveWS yes ]
 --   before/after results from this function agree does not mean that
 --   the document was successfully unpickled!
 --
-pickle_unpickle :: XmlPickler a
-                => String
-                -> FilePath
+pickle_unpickle :: PU a -- ^ @unpickler@ returning an @a@
+                -> FilePath -- ^ Path to the document to unpickle.
                 -> IO ([a], [a])
-pickle_unpickle root_element filepath = do
+pickle_unpickle unpickler filepath = do
   -- We need to check only the root message element since
   -- readDocument produces a bunch of other junk.
     expected <- runX arr_getobj
     actual <- runX $ arr_getobj
                      >>>
-                     xpickleVal xpickle
+                     xpickleVal unpickler
                      >>>
-                     xunpickleVal xpickle
+                     xunpickleVal unpickler
 
     return (expected, actual)
   where
     arr_getobj = readDocument parse_opts filepath
                    />
-                   hasName root_element
+                   isElem -- Drop the extra junk readDocument pulls in.
                    >>>
-                   xunpickleVal xpickle
+                   xunpickleVal unpickler
 
 
 
@@ -101,7 +104,10 @@ pickle_unpickle root_element filepath = do
 --   would result. By taking the unpickler as an argument, we allow
 --   the caller to indirectly specify a concrete type.
 --
-unpickleable :: XmlPickler a => FilePath -> PU a -> IO Bool
+--   Apologies the the name; unpickleable means \"we can unpickle
+--   it\", not \"not pickleable.\"
+--
+unpickleable :: FilePath -> PU a -> IO Bool
 unpickleable filepath unpickler = do
   xmldoc <- try_unpickle `catch` (\(SomeException _) -> return [])
   return $ (not . null) xmldoc