Add document for phantom typed SQL expression.

relational-join/src/Database/Relational/Query/Expr.hs

@@ -1,12 +1,26 @@
 {-# LANGUAGE FlexibleInstances #-}
 
+-- |
+-- Module      : Database.Relational.Query.Expr
+-- Copyright   : 2013 Kei Hibino
+-- License     : BSD3
+--
+-- Maintainer  : ex8k.hibino@gmail.com
+-- Stability   : experimental
+-- Portability : unknown
+--
+-- This module defines phantom typed SQL expression object.
+-- Contains normal interfaces.
 module Database.Relational.Query.Expr (
+  -- * Typed SQL Expression
   Expr, showExpr,
 
+  -- * Constant SQL Expression
   ShowConstantSQL (showConstantSQL),
 
   valueExpr,
 
+  -- * Type conversion
   just, flattenMaybe,
 
   fromTriBool, exprAnd
@@ -25,67 +39,86 @@ import qualified Language.SQL.Keyword as SQL
 import qualified Language.SQL.Keyword.ConcatString as SQLs
 
 
+-- | Constant integral SQL expression.
 intExprSQL :: (Show a, Integral a) => a -> String
 intExprSQL =  show
 
+-- | Escape 'String' for constant SQL string expression.
 escapeStringToSqlExpr :: String -> String
 escapeStringToSqlExpr =  rec  where
   rec ""        = ""
   rec ('\'':cs) = '\'' : '\'' : rec cs
   rec (c:cs)    = c : rec cs
 
+-- | From 'String' into constant SQL string expression.
 stringExprSQL :: String -> String
 stringExprSQL =  ('\'':) . (++ "'") . escapeStringToSqlExpr
 
+-- | Interface for constant SQL expression.
 class ShowConstantSQL a where
   showConstantSQL :: a -> String
 
+-- | Constant SQL expression of 'Int16'.
 instance ShowConstantSQL Int16 where
   showConstantSQL = intExprSQL
 
+-- | Constant SQL expression of 'Int32'.
 instance ShowConstantSQL Int32 where
   showConstantSQL = intExprSQL
 
+-- | Constant SQL expression of 'Int64'.
 instance ShowConstantSQL Int64 where
   showConstantSQL = intExprSQL
 
+-- | Constant SQL expression of 'String'.
 instance ShowConstantSQL String where
   showConstantSQL = stringExprSQL
 
+-- | Constant SQL expression of 'ByteString'.
 instance ShowConstantSQL ByteString where
   showConstantSQL = stringExprSQL . BS.unpack
 
+-- | Constant SQL expression of 'Text'.
 instance ShowConstantSQL Text where
   showConstantSQL = stringExprSQL . T.unpack
 
+-- | Constant SQL expression of 'Char'.
 instance ShowConstantSQL Char where
   showConstantSQL = stringExprSQL . (:"")
 
+-- | Constant SQL expression of 'Bool'.
 instance ShowConstantSQL Bool where
   showConstantSQL = d  where
     d True  = "(0=0)"
     d False = "(0=1)"
 
+-- | Inference rule for Constant SQL expression of 'Maybe' type.
 instance ShowConstantSQL a => ShowConstantSQL (Maybe a) where
   showConstantSQL = d  where
     d (Just a)  = showConstantSQL a
     d (Nothing) = "NULL"
 
 
+-- | Typed constant SQL expression from Haskell value.
 valueExpr :: ShowConstantSQL ft => ft -> Expr ft
 valueExpr =  Expr . showConstantSQL
 
+-- | Unsafely cast phantom type.
 unsafeCastExpr :: Expr a -> Expr b
 unsafeCastExpr =  Expr . showExpr
 
+-- | Convert phantom type into 'Maybe'.
 just :: Expr ft -> Expr (Maybe ft)
 just =  unsafeCastExpr
 
+-- | Join nested 'Maybe' phantom type.
 flattenMaybe :: Expr (Maybe (Maybe ft)) -> Expr (Maybe ft)
 flattenMaybe =  unsafeCastExpr
 
+-- | Unsafely fromJust of phantom typed 'Maybe' 'Bool'.
 fromTriBool :: Expr (Maybe Bool) -> Expr Bool
 fromTriBool =  unsafeCastExpr
 
+-- | AND operator for 'Expr'.
 exprAnd :: Expr Bool -> Expr Bool -> Expr Bool
 exprAnd a b = Expr $ '(' : SQLs.defineBinOp SQL.AND (showExpr a) (showExpr b) ++ [')']

relational-join/src/Database/Relational/Query/Expr/Unsafe.hs

@@ -1,12 +1,26 @@
-
+-- |
+-- Module      : Database.Relational.Query.Expr.Unsafe
+-- Copyright   : 2013 Kei Hibino
+-- License     : BSD3
+--
+-- Maintainer  : ex8k.hibino@gmail.com
+-- Stability   : experimental
+-- Portability : unknown
+--
+-- This module defines phantom typed SQL expression object.
+-- Contains internal structure and unsafe interfaces.
 module Database.Relational.Query.Expr.Unsafe (
+  -- * Typed SQL Expression
   Expr(Expr), showExpr
   ) where
 
+-- | Phantom typed SQL expression object.
 newtype Expr a = Expr (String)
 
+-- | Get SQL expression from typed object.
 showExpr :: Expr t -> String
 showExpr (Expr s) = s
 
+-- | Show expression.
 instance Show (Expr a) where
   show = showExpr