support character set literals, e.g. N'stuff'

support collate postfix operator
support escape and uescape as postfix operators
change the collate support in substring and trim which isn't a special
  case in the sql 2003 grammar anymore but just a normal collate postfix
  operator, the old code had the collation name as a string, but the
  new style is as an identifier

tools/Language/SQL/SimpleSQL/SQL2003.lhs

@@ -17,9 +17,9 @@ large amount of the SQL.
 > sql2003Tests :: TestItem
 > sql2003Tests = Group "sql2003Tests"
 >     [stringLiterals
->     --,nationalCharacterStringLiterals
->     --,unicodeStringLiterals
->     --,binaryStringLiterals
+>     ,nationalCharacterStringLiterals
+>     ,unicodeStringLiterals
+>     ,binaryStringLiterals
 >     ,numericLiterals
 >     ,dateAndTimeLiterals
 >     ,booleanLiterals
@@ -43,6 +43,7 @@ large amount of the SQL.
 >     ,quantifiedComparisonPredicate
 >     ,uniquePredicate
 >     ,matchPredicate
+>     ,collateClause
 >     --,sortSpecificationList
 >     ]
 
@@ -479,10 +480,16 @@ The <quote symbol> rule consists of two immediately adjacent <quote> marks with
 >      ,StringLit "something some moreand more")
 >     ,("'a quote: '', stuff'"
 >      ,StringLit "a quote: ', stuff")
+>     ,("''"
+>      ,StringLit "")
+>     ,("_francais 'français'"
+>      ,TypedLit (TypeName "_francais") "français")
 >     ]
 
 TODO: all the stuff with character set representations.
 
+
+
 == other string literals
 
 <national character string literal>    ::= 
@@ -491,8 +498,8 @@ TODO: all the stuff with character set representations.
 
 > nationalCharacterStringLiterals :: TestItem
 > nationalCharacterStringLiterals = Group "national character string literals" $ map (uncurry TestValueExpr)
->     [("N'something'", undefined)
->     ,("n'something'", undefined)
+>     [("N'something'", CSStringLit "N" "something")
+>     ,("n'something'", CSStringLit "n" "something")
 >     ]
 
 <Unicode character string literal>    ::= 
@@ -505,14 +512,13 @@ TODO: all the stuff with character set representations.
 
 > unicodeStringLiterals :: TestItem
 > unicodeStringLiterals = Group "national character string literals" $ map (uncurry TestValueExpr)
->     [("U&'something'", undefined)
->     ,("u&'something'", undefined)
+>     [("U&'something'", CSStringLit "U&" "something")
+>     ,("u&'something' escape ="
+>      ,Escape (CSStringLit "u&" "something") '=')
+>     ,("u&'something' uescape ="
+>      ,UEscape (CSStringLit "u&" "something") '=')
 >     ]
 
-TODO: put in some unicode and some unicode escape values plus work out
-the ESCAPE thing. I think this is to change the unicode escape value
-starting character.
-
 == other string literals
 
 <binary string literal>    ::= 
@@ -529,8 +535,9 @@ TODO: how to escapes work here?
 
 > binaryStringLiterals :: TestItem
 > binaryStringLiterals = Group "bit and hex string literals" $ map (uncurry TestValueExpr)
->     [("B'101010'", undefined)
->     ,("X'7f7f7f'", undefined)
+>     [("B'101010'", CSStringLit "B" "101010")
+>     ,("X'7f7f7f'", CSStringLit "X" "7f7f7f")
+>     ,("X'7f7f7f' escape z", Escape (CSStringLit "X" "7f7f7f") 'z')
 >     ]
 
 TODO: separator stuff for all the string literals?
@@ -2802,7 +2809,10 @@ Specify a default collating sequence.
 
 <collate clause>    ::=   COLLATE <collation name>
 
-covered elsewhere
+> collateClause :: TestItem
+> collateClause = Group "collate clause" $ map (uncurry TestValueExpr)
+>     [("a collate my_collation"
+>      ,Collate (Iden "a") "my_collation")]
 
 10.8 <constraint name definition> and <constraint characteristics> (p501)
 

tools/Language/SQL/SimpleSQL/ValueExprs.lhs

@@ -243,10 +243,10 @@ keyword special operators
 >     ,("substring(x for 2)"
 >      ,SpecialOpK "substring" (Just $ Iden "x") [("for", NumLit "2")])
 
->     ,("substring(x from 1 for 2 collate 'C')"
->      ,SpecialOpK "substring" (Just $ Iden "x") [("from", NumLit "1")
->                                                ,("for", NumLit "2")
->                                                ,("collate", StringLit "C")])
+>     ,("substring(x from 1 for 2 collate C)"
+>      ,SpecialOpK "substring" (Just $ Iden "x")
+>           [("from", NumLit "1")
+>           ,("for", Collate (NumLit "2") "C")])
 
 this doesn't work because of a overlap in the 'in' parser
 
@@ -312,11 +312,10 @@ target_string
 >           [("trailing", StringLit "y")
 >           ,("from", Iden "target_string")])
 
->     ,("trim(both 'z' from target_string collate 'C')"
+>     ,("trim(both 'z' from target_string collate C)"
 >      ,SpecialOpK "trim" Nothing
 >           [("both", StringLit "z")
->           ,("from", Iden "target_string")
->           ,("collate", StringLit "C")])
+>           ,("from", Collate (Iden "target_string") "C")])
 
 >     ,("trim(leading from target_string)"
 >      ,SpecialOpK "trim" Nothing