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{-# LANGUAGE ParallelListComp, TemplateHaskell #-} |
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|
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{-| TemplateHaskell helper for Ganeti Haskell code. |
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|
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As TemplateHaskell require that splices be defined in a separate |
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module, we combine all the TemplateHaskell functionality that HTools |
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needs in this module (except the one for unittests). |
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|
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-} |
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|
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{- |
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|
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Copyright (C) 2011, 2012, 2013, 2014 Google Inc. |
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|
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This program is free software; you can redistribute it and/or modify |
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it under the terms of the GNU General Public License as published by |
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the Free Software Foundation; either version 2 of the License, or |
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(at your option) any later version. |
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|
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This program is distributed in the hope that it will be useful, but |
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WITHOUT ANY WARRANTY; without even the implied warranty of |
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
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General Public License for more details. |
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|
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You should have received a copy of the GNU General Public License |
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along with this program; if not, write to the Free Software |
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Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA |
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02110-1301, USA. |
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|
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-} |
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|
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module Ganeti.THH ( declareSADT |
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, declareLADT |
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, declareILADT |
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, declareIADT |
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, makeJSONInstance |
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, deCamelCase |
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, genOpID |
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, genOpLowerStrip |
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, genAllConstr |
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, genAllOpIDs |
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, PyValue(..) |
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, PyValueEx(..) |
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, OpCodeField(..) |
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, OpCodeDescriptor(..) |
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, genOpCode |
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, genStrOfOp |
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, genStrOfKey |
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, genLuxiOp |
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, Field (..) |
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, simpleField |
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, andRestArguments |
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, specialNumericalField |
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, timeAsDoubleField |
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, withDoc |
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, defaultField |
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, optionalField |
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, optionalNullSerField |
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, renameField |
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, customField |
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, timeStampFields |
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, uuidFields |
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, serialFields |
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, tagsFields |
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, TagSet |
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, buildObject |
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, buildObjectSerialisation |
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, buildParam |
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, DictObject(..) |
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, ArrayObject(..) |
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, genException |
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, excErrMsg |
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) where |
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|
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import Control.Arrow ((&&&)) |
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import Control.Applicative |
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import Control.Monad |
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import Control.Monad.Base () -- Needed to prevent spurious GHC linking errors. |
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import Data.Attoparsec () -- Needed to prevent spurious GHC 7.4 linking errors. |
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-- See issue #683 and https://ghc.haskell.org/trac/ghc/ticket/4899 |
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import Data.Char |
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import Data.List |
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import Data.Maybe |
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import qualified Data.Map as M |
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import qualified Data.Set as Set |
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import Language.Haskell.TH |
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import Language.Haskell.TH.Syntax (lift) |
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import System.Time (ClockTime(..)) |
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|
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import qualified Text.JSON as JSON |
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import Text.JSON.Pretty (pp_value) |
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|
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import Ganeti.JSON |
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import Ganeti.PyValue |
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import Ganeti.THH.PyType |
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|
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|
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-- * Exported types |
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|
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-- | Class of objects that can be converted from and to 'JSObject' |
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-- lists-format. |
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class DictObject a where |
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toDict :: a -> [(String, JSON.JSValue)] |
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fromDict :: [(String, JSON.JSValue)] -> JSON.Result a |
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|
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-- | Class of objects that can be converted from and to @[JSValue]@ with |
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-- a fixed length and order. |
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class ArrayObject a where |
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toJSArray :: a -> [JSON.JSValue] |
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fromJSArray :: [JSON.JSValue] -> JSON.Result a |
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|
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-- | Optional field information. |
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data OptionalType |
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= NotOptional -- ^ Field is not optional |
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| OptionalOmitNull -- ^ Field is optional, null is not serialised |
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| OptionalSerializeNull -- ^ Field is optional, null is serialised |
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| AndRestArguments -- ^ Special field capturing all the remaining fields |
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-- as plain JSON values |
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deriving (Show, Eq) |
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|
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-- | Serialised field data type describing how to generate code for the field. |
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-- Each field has a type, which isn't captured in the type of the data type, |
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-- but is saved in the 'Q' monad in 'fieldType'. |
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-- |
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-- Let @t@ be a type we want to parametrize the field with. There are the |
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-- following possible types of fields: |
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-- |
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-- [Mandatory with no default.] Then @fieldType@ holds @t@, |
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-- @fieldDefault = Nothing@ and @fieldIsOptional = NotOptional@. |
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-- |
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-- [Field with a default value.] Then @fieldType@ holds @t@ and |
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-- @fieldDefault = Just exp@ where @exp@ is an expression of type @t@ and |
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-- @fieldIsOptional = NotOptional@. |
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-- |
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-- [Optional, no default value.] Then @fieldType@ holds @Maybe t@, |
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-- @fieldDefault = Nothing@ and @fieldIsOptional@ is either |
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-- 'OptionalOmitNull' or 'OptionalSerializeNull'. |
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-- |
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-- Optional fields with a default value are prohibited, as their main |
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-- intention is to represent the information that a request didn't contain |
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-- the field data. |
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-- |
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-- /Custom (de)serialization:/ |
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-- Field can have custom (de)serialization functions that are stored in |
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-- 'fieldRead' and 'fieldShow'. If they aren't provided, the default is to use |
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-- 'readJSON' and 'showJSON' for the field's type @t@. If they are provided, |
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-- the type of the contained deserializing expression must be |
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-- |
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-- @ |
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-- [(String, JSON.JSValue)] -> JSON.JSValue -> JSON.Result t |
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-- @ |
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-- |
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-- where the first argument carries the whole record in the case the |
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-- deserializing function needs to process additional information. |
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-- |
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-- The type of the contained serializing experssion must be |
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-- |
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-- @ |
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-- t -> (JSON.JSValue, [(String, JSON.JSValue)]) |
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-- @ |
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-- |
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-- where the result can provide extra JSON fields to include in the output |
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-- record (or just return @[]@ if they're not needed). |
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-- |
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-- Note that for optional fields the type appearing in the custom functions |
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-- is still @t@. Therefore making a field optional doesn't change the |
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-- functions. |
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-- |
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-- There is also a special type of optional field 'AndRestArguments' which |
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-- allows to parse any additional arguments not covered by other fields. There |
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-- can be at most one such special field and it's type must be |
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-- @Map String JSON.JSValue@. See also 'andRestArguments'. |
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data Field = Field { fieldName :: String |
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, fieldType :: Q Type |
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-- ^ the type of the field, @t@ for non-optional fields, |
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-- @Maybe t@ for optional ones. |
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, fieldRead :: Maybe (Q Exp) |
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-- ^ an optional custom deserialization function of type |
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-- @[(String, JSON.JSValue)] -> JSON.JSValue -> |
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-- JSON.Result t@ |
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, fieldShow :: Maybe (Q Exp) |
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-- ^ an optional custom serialization function of type |
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-- @t -> (JSON.JSValue, [(String, JSON.JSValue)])@ |
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, fieldExtraKeys :: [String] |
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-- ^ a list of extra keys added by 'fieldShow' |
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, fieldDefault :: Maybe (Q Exp) |
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-- ^ an optional default value of type @t@ |
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, fieldConstr :: Maybe String |
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, fieldIsOptional :: OptionalType |
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-- ^ determines if a field is optional, and if yes, |
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-- how |
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, fieldDoc :: String |
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} |
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|
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-- | Generates a simple field. |
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simpleField :: String -> Q Type -> Field |
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simpleField fname ftype = |
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Field { fieldName = fname |
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, fieldType = ftype |
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, fieldRead = Nothing |
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, fieldShow = Nothing |
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, fieldExtraKeys = [] |
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, fieldDefault = Nothing |
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, fieldConstr = Nothing |
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, fieldIsOptional = NotOptional |
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, fieldDoc = "" |
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} |
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|
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-- | Generate an AndRestArguments catch-all field. |
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andRestArguments :: String -> Field |
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andRestArguments fname = |
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Field { fieldName = fname |
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, fieldType = [t| M.Map String JSON.JSValue |] |
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, fieldRead = Nothing |
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, fieldShow = Nothing |
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, fieldExtraKeys = [] |
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, fieldDefault = Nothing |
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, fieldConstr = Nothing |
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, fieldIsOptional = AndRestArguments |
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, fieldDoc = "" |
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} |
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|
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withDoc :: String -> Field -> Field |
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withDoc doc field = |
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field { fieldDoc = doc } |
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|
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-- | Sets the renamed constructor field. |
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renameField :: String -> Field -> Field |
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renameField constrName field = field { fieldConstr = Just constrName } |
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|
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-- | Sets the default value on a field (makes it optional with a |
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-- default value). |
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defaultField :: Q Exp -> Field -> Field |
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defaultField defval field = field { fieldDefault = Just defval } |
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|
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-- | Marks a field optional (turning its base type into a Maybe). |
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optionalField :: Field -> Field |
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optionalField field = field { fieldIsOptional = OptionalOmitNull } |
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|
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-- | Marks a field optional (turning its base type into a Maybe), but |
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-- with 'Nothing' serialised explicitly as /null/. |
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optionalNullSerField :: Field -> Field |
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optionalNullSerField field = field { fieldIsOptional = OptionalSerializeNull } |
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|
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-- | Wrapper around a special parse function, suitable as field-parsing |
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-- function. |
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numericalReadFn :: JSON.JSON a => (String -> JSON.Result a) |
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-> [(String, JSON.JSValue)] -> JSON.JSValue -> JSON.Result a |
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numericalReadFn _ _ v@(JSON.JSRational _ _) = JSON.readJSON v |
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numericalReadFn f _ (JSON.JSString x) = f $ JSON.fromJSString x |
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numericalReadFn _ _ _ = JSON.Error "A numerical field has to be a number or\ |
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\ a string." |
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|
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-- | Sets the read function to also accept string parsable by the given |
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-- function. |
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specialNumericalField :: Name -> Field -> Field |
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specialNumericalField f field = |
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field { fieldRead = Just (appE (varE 'numericalReadFn) (varE f)) } |
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|
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-- | Creates a new mandatory field that reads time as the (floating point) |
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-- number of seconds since the standard UNIX epoch, and represents it in |
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-- Haskell as 'ClockTime'. |
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timeAsDoubleField :: String -> Field |
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timeAsDoubleField fname = |
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(simpleField fname [t| ClockTime |]) |
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{ fieldRead = Just $ [| \_ -> liftM unTimeAsDoubleJSON . JSON.readJSON |] |
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, fieldShow = Just $ [| \c -> (JSON.showJSON $ TimeAsDoubleJSON c, []) |] |
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} |
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|
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-- | Sets custom functions on a field. |
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customField :: Name -- ^ The name of the read function |
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-> Name -- ^ The name of the show function |
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-> [String] -- ^ The name of extra field keys |
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-> Field -- ^ The original field |
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-> Field -- ^ Updated field |
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customField readfn showfn extra field = |
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field { fieldRead = Just (varE readfn), fieldShow = Just (varE showfn) |
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, fieldExtraKeys = extra } |
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|
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-- | Computes the record name for a given field, based on either the |
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-- string value in the JSON serialisation or the custom named if any |
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-- exists. |
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fieldRecordName :: Field -> String |
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fieldRecordName (Field { fieldName = name, fieldConstr = alias }) = |
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fromMaybe (camelCase name) alias |
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|
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-- | Computes the preferred variable name to use for the value of this |
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-- field. If the field has a specific constructor name, then we use a |
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-- first-letter-lowercased version of that; otherwise, we simply use |
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-- the field name. See also 'fieldRecordName'. |
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fieldVariable :: Field -> String |
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fieldVariable f = |
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case (fieldConstr f) of |
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Just name -> ensureLower name |
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_ -> map (\c -> if c == '-' then '_' else c) $ fieldName f |
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|
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-- | Compute the actual field type (taking into account possible |
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-- optional status). |
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actualFieldType :: Field -> Q Type |
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actualFieldType f | fieldIsOptional f `elem` [NotOptional, AndRestArguments] = t |
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| otherwise = [t| Maybe $t |] |
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where t = fieldType f |
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|
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-- | Checks that a given field is not optional (for object types or |
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-- fields which should not allow this case). |
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checkNonOptDef :: (Monad m) => Field -> m () |
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checkNonOptDef (Field { fieldIsOptional = OptionalOmitNull |
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, fieldName = name }) = |
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fail $ "Optional field " ++ name ++ " used in parameter declaration" |
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checkNonOptDef (Field { fieldIsOptional = OptionalSerializeNull |
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, fieldName = name }) = |
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fail $ "Optional field " ++ name ++ " used in parameter declaration" |
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checkNonOptDef (Field { fieldDefault = (Just _), fieldName = name }) = |
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fail $ "Default field " ++ name ++ " used in parameter declaration" |
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checkNonOptDef _ = return () |
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|
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-- | Construct a function that parses a field value. If the field has |
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-- a custom 'fieldRead', it's applied to @o@ and used. Otherwise |
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-- @JSON.readJSON@ is used. |
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parseFn :: Field -- ^ The field definition |
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-> Q Exp -- ^ The entire object in JSON object format |
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-> Q Exp -- ^ The resulting function that parses a JSON message |
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parseFn field o |
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= maybe [| readJSONWithDesc $(stringE $ fieldName field) False |] |
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(`appE` o) (fieldRead field) |
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|
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-- | Produces the expression that will de-serialise a given |
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-- field. Since some custom parsing functions might need to use the |
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-- entire object, we do take and pass the object to any custom read |
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-- functions. |
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loadFn :: Field -- ^ The field definition |
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-> Q Exp -- ^ The value of the field as existing in the JSON message |
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-> Q Exp -- ^ The entire object in JSON object format |
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-> Q Exp -- ^ Resulting expression |
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loadFn field expr o = [| $expr >>= $(parseFn field o) |] |
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|
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-- | Just as 'loadFn', but for optional fields. |
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loadFnOpt :: Field -- ^ The field definition |
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-> Q Exp -- ^ The value of the field as existing in the JSON message |
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-- as Maybe |
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-> Q Exp -- ^ The entire object in JSON object format |
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-> Q Exp -- ^ Resulting expression |
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loadFnOpt field@(Field { fieldDefault = Just def }) expr o |
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= case fieldIsOptional field of |
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NotOptional -> [| $expr >>= maybe (return $def) $(parseFn field o) |] |
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_ -> fail $ "Field " ++ fieldName field ++ ":\ |
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\ A field can't be optional and\ |
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\ have a default value at the same time." |
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loadFnOpt field expr o |
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= [| $expr >>= maybe (return Nothing) (liftM Just . $(parseFn field o)) |] |
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|
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-- * Common field declarations |
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|
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-- | Timestamp fields description. |
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timeStampFields :: [Field] |
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timeStampFields = map (defaultField [| TOD 0 0 |] . timeAsDoubleField) |
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["ctime", "mtime"] |
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|
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|
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-- | Serial number fields description. |
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serialFields :: [Field] |
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serialFields = |
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[ renameField "Serial" $ simpleField "serial_no" [t| Int |] ] |
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|
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-- | UUID fields description. |
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uuidFields :: [Field] |
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uuidFields = [ simpleField "uuid" [t| String |] ] |
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|
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-- | Tag set type alias. |
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type TagSet = Set.Set String |
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|
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-- | Tag field description. |
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tagsFields :: [Field] |
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tagsFields = [ defaultField [| Set.empty |] $ |
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simpleField "tags" [t| TagSet |] ] |
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|
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-- * Internal types |
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|
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-- | A simple field, in constrast to the customisable 'Field' type. |
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type SimpleField = (String, Q Type) |
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|
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-- | A definition for a single constructor for a simple object. |
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type SimpleConstructor = (String, [SimpleField]) |
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|
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-- | A definition for ADTs with simple fields. |
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type SimpleObject = [SimpleConstructor] |
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|
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-- | A type alias for an opcode constructor of a regular object. |
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type OpCodeConstructor = (String, Q Type, String, [Field], String) |
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|
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-- | A type alias for a Luxi constructor of a regular object. |
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type LuxiConstructor = (String, [Field]) |
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|
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-- * Helper functions |
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|
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-- | Ensure first letter is lowercase. |
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-- |
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-- Used to convert type name to function prefix, e.g. in @data Aa -> |
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-- aaToRaw@. |
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ensureLower :: String -> String |
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ensureLower [] = [] |
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ensureLower (x:xs) = toLower x:xs |
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|
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-- | Ensure first letter is uppercase. |
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-- |
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-- Used to convert constructor name to component |
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ensureUpper :: String -> String |
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ensureUpper [] = [] |
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ensureUpper (x:xs) = toUpper x:xs |
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|
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-- | Helper for quoted expressions. |
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varNameE :: String -> Q Exp |
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varNameE = varE . mkName |
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|
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-- | showJSON as an expression, for reuse. |
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showJSONE :: Q Exp |
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showJSONE = varE 'JSON.showJSON |
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|
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-- | makeObj as an expression, for reuse. |
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makeObjE :: Q Exp |
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makeObjE = varE 'JSON.makeObj |
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|
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-- | fromObj (Ganeti specific) as an expression, for reuse. |
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fromObjE :: Q Exp |
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fromObjE = varE 'fromObj |
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|
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-- | ToRaw function name. |
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toRawName :: String -> Name |
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toRawName = mkName . (++ "ToRaw") . ensureLower |
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|
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-- | FromRaw function name. |
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fromRawName :: String -> Name |
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fromRawName = mkName . (++ "FromRaw") . ensureLower |
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|
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-- | Converts a name to it's varE\/litE representations. |
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reprE :: Either String Name -> Q Exp |
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reprE = either stringE varE |
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|
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-- | Smarter function application. |
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-- |
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-- This does simply f x, except that if is 'id', it will skip it, in |
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-- order to generate more readable code when using -ddump-splices. |
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appFn :: Exp -> Exp -> Exp |
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appFn f x | f == VarE 'id = x |
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| otherwise = AppE f x |
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|
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-- | Builds a field for a normal constructor. |
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buildConsField :: Q Type -> StrictTypeQ |
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buildConsField ftype = do |
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ftype' <- ftype |
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return (NotStrict, ftype') |
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|
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-- | Builds a constructor based on a simple definition (not field-based). |
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buildSimpleCons :: Name -> SimpleObject -> Q Dec |
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buildSimpleCons tname cons = do |
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decl_d <- mapM (\(cname, fields) -> do |
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fields' <- mapM (buildConsField . snd) fields |
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return $ NormalC (mkName cname) fields') cons |
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return $ DataD [] tname [] decl_d [''Show, ''Eq] |
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|
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-- | Generate the save function for a given type. |
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genSaveSimpleObj :: Name -- ^ Object type |
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-> String -- ^ Function name |
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-> SimpleObject -- ^ Object definition |
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-> (SimpleConstructor -> Q Clause) -- ^ Constructor save fn |
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-> Q (Dec, Dec) |
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genSaveSimpleObj tname sname opdefs fn = do |
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let sigt = AppT (AppT ArrowT (ConT tname)) (ConT ''JSON.JSValue) |
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fname = mkName sname |
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cclauses <- mapM fn opdefs |
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return $ (SigD fname sigt, FunD fname cclauses) |
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|
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-- * Template code for simple raw type-equivalent ADTs |
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|
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-- | Generates a data type declaration. |
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-- |
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-- The type will have a fixed list of instances. |
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strADTDecl :: Name -> [String] -> Dec |
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strADTDecl name constructors = |
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DataD [] name [] |
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(map (flip NormalC [] . mkName) constructors) |
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[''Show, ''Eq, ''Enum, ''Bounded, ''Ord] |
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|
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-- | Generates a toRaw function. |
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-- |
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-- This generates a simple function of the form: |
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-- |
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-- @ |
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-- nameToRaw :: Name -> /traw/ |
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-- nameToRaw Cons1 = var1 |
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-- nameToRaw Cons2 = \"value2\" |
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-- @ |
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genToRaw :: Name -> Name -> Name -> [(String, Either String Name)] -> Q [Dec] |
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genToRaw traw fname tname constructors = do |
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let sigt = AppT (AppT ArrowT (ConT tname)) (ConT traw) |
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-- the body clauses, matching on the constructor and returning the |
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-- raw value |
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clauses <- mapM (\(c, v) -> clause [recP (mkName c) []] |
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(normalB (reprE v)) []) constructors |
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return [SigD fname sigt, FunD fname clauses] |
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|
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-- | Generates a fromRaw function. |
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-- |
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-- The function generated is monadic and can fail parsing the |
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-- raw value. It is of the form: |
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-- |
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-- @ |
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-- nameFromRaw :: (Monad m) => /traw/ -> m Name |
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-- nameFromRaw s | s == var1 = Cons1 |
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-- | s == \"value2\" = Cons2 |
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-- | otherwise = fail /.../ |
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-- @ |
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genFromRaw :: Name -> Name -> Name -> [(String, Either String Name)] -> Q [Dec] |
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genFromRaw traw fname tname constructors = do |
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-- signature of form (Monad m) => String -> m $name |
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sigt <- [t| (Monad m) => $(conT traw) -> m $(conT tname) |] |
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-- clauses for a guarded pattern |
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let varp = mkName "s" |
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varpe = varE varp |
520 |
clauses <- mapM (\(c, v) -> do |
521 |
-- the clause match condition |
522 |
g <- normalG [| $varpe == $(reprE v) |] |
523 |
-- the clause result |
524 |
r <- [| return $(conE (mkName c)) |] |
525 |
return (g, r)) constructors |
526 |
-- the otherwise clause (fallback) |
527 |
oth_clause <- do |
528 |
g <- normalG [| otherwise |] |
529 |
r <- [|fail ("Invalid string value for type " ++ |
530 |
$(litE (stringL (nameBase tname))) ++ ": " ++ show $varpe) |] |
531 |
return (g, r) |
532 |
let fun = FunD fname [Clause [VarP varp] |
533 |
(GuardedB (clauses++[oth_clause])) []] |
534 |
return [SigD fname sigt, fun] |
535 |
|
536 |
-- | Generates a data type from a given raw format. |
537 |
-- |
538 |
-- The format is expected to multiline. The first line contains the |
539 |
-- type name, and the rest of the lines must contain two words: the |
540 |
-- constructor name and then the string representation of the |
541 |
-- respective constructor. |
542 |
-- |
543 |
-- The function will generate the data type declaration, and then two |
544 |
-- functions: |
545 |
-- |
546 |
-- * /name/ToRaw, which converts the type to a raw type |
547 |
-- |
548 |
-- * /name/FromRaw, which (monadically) converts from a raw type to the type |
549 |
-- |
550 |
-- Note that this is basically just a custom show\/read instance, |
551 |
-- nothing else. |
552 |
declareADT |
553 |
:: (a -> Either String Name) -> Name -> String -> [(String, a)] -> Q [Dec] |
554 |
declareADT fn traw sname cons = do |
555 |
let name = mkName sname |
556 |
ddecl = strADTDecl name (map fst cons) |
557 |
-- process cons in the format expected by genToRaw |
558 |
cons' = map (\(a, b) -> (a, fn b)) cons |
559 |
toraw <- genToRaw traw (toRawName sname) name cons' |
560 |
fromraw <- genFromRaw traw (fromRawName sname) name cons' |
561 |
return $ ddecl:toraw ++ fromraw |
562 |
|
563 |
declareLADT :: Name -> String -> [(String, String)] -> Q [Dec] |
564 |
declareLADT = declareADT Left |
565 |
|
566 |
declareILADT :: String -> [(String, Int)] -> Q [Dec] |
567 |
declareILADT sname cons = do |
568 |
consNames <- sequence [ newName ('_':n) | (n, _) <- cons ] |
569 |
consFns <- concat <$> sequence |
570 |
[ do sig <- sigD n [t| Int |] |
571 |
let expr = litE (IntegerL (toInteger i)) |
572 |
fn <- funD n [clause [] (normalB expr) []] |
573 |
return [sig, fn] |
574 |
| n <- consNames |
575 |
| (_, i) <- cons ] |
576 |
let cons' = [ (n, n') | (n, _) <- cons | n' <- consNames ] |
577 |
(consFns ++) <$> declareADT Right ''Int sname cons' |
578 |
|
579 |
declareIADT :: String -> [(String, Name)] -> Q [Dec] |
580 |
declareIADT = declareADT Right ''Int |
581 |
|
582 |
declareSADT :: String -> [(String, Name)] -> Q [Dec] |
583 |
declareSADT = declareADT Right ''String |
584 |
|
585 |
-- | Creates the showJSON member of a JSON instance declaration. |
586 |
-- |
587 |
-- This will create what is the equivalent of: |
588 |
-- |
589 |
-- @ |
590 |
-- showJSON = showJSON . /name/ToRaw |
591 |
-- @ |
592 |
-- |
593 |
-- in an instance JSON /name/ declaration |
594 |
genShowJSON :: String -> Q Dec |
595 |
genShowJSON name = do |
596 |
body <- [| JSON.showJSON . $(varE (toRawName name)) |] |
597 |
return $ FunD 'JSON.showJSON [Clause [] (NormalB body) []] |
598 |
|
599 |
-- | Creates the readJSON member of a JSON instance declaration. |
600 |
-- |
601 |
-- This will create what is the equivalent of: |
602 |
-- |
603 |
-- @ |
604 |
-- readJSON s = case readJSON s of |
605 |
-- Ok s' -> /name/FromRaw s' |
606 |
-- Error e -> Error /description/ |
607 |
-- @ |
608 |
-- |
609 |
-- in an instance JSON /name/ declaration |
610 |
genReadJSON :: String -> Q Dec |
611 |
genReadJSON name = do |
612 |
let s = mkName "s" |
613 |
body <- [| $(varE (fromRawName name)) =<< |
614 |
readJSONWithDesc $(stringE name) True $(varE s) |] |
615 |
return $ FunD 'JSON.readJSON [Clause [VarP s] (NormalB body) []] |
616 |
|
617 |
-- | Generates a JSON instance for a given type. |
618 |
-- |
619 |
-- This assumes that the /name/ToRaw and /name/FromRaw functions |
620 |
-- have been defined as by the 'declareSADT' function. |
621 |
makeJSONInstance :: Name -> Q [Dec] |
622 |
makeJSONInstance name = do |
623 |
let base = nameBase name |
624 |
showJ <- genShowJSON base |
625 |
readJ <- genReadJSON base |
626 |
return [InstanceD [] (AppT (ConT ''JSON.JSON) (ConT name)) [readJ,showJ]] |
627 |
|
628 |
-- * Template code for opcodes |
629 |
|
630 |
-- | Transforms a CamelCase string into an_underscore_based_one. |
631 |
deCamelCase :: String -> String |
632 |
deCamelCase = |
633 |
intercalate "_" . map (map toUpper) . groupBy (\_ b -> not $ isUpper b) |
634 |
|
635 |
-- | Transform an underscore_name into a CamelCase one. |
636 |
camelCase :: String -> String |
637 |
camelCase = concatMap (ensureUpper . drop 1) . |
638 |
groupBy (\_ b -> b /= '_' && b /= '-') . ('_':) |
639 |
|
640 |
-- | Computes the name of a given constructor. |
641 |
constructorName :: Con -> Q Name |
642 |
constructorName (NormalC name _) = return name |
643 |
constructorName (RecC name _) = return name |
644 |
constructorName x = fail $ "Unhandled constructor " ++ show x |
645 |
|
646 |
-- | Extract all constructor names from a given type. |
647 |
reifyConsNames :: Name -> Q [String] |
648 |
reifyConsNames name = do |
649 |
reify_result <- reify name |
650 |
case reify_result of |
651 |
TyConI (DataD _ _ _ cons _) -> mapM (liftM nameBase . constructorName) cons |
652 |
o -> fail $ "Unhandled name passed to reifyConsNames, expected\ |
653 |
\ type constructor but got '" ++ show o ++ "'" |
654 |
|
655 |
-- | Builds the generic constructor-to-string function. |
656 |
-- |
657 |
-- This generates a simple function of the following form: |
658 |
-- |
659 |
-- @ |
660 |
-- fname (ConStructorOne {}) = trans_fun("ConStructorOne") |
661 |
-- fname (ConStructorTwo {}) = trans_fun("ConStructorTwo") |
662 |
-- @ |
663 |
-- |
664 |
-- This builds a custom list of name\/string pairs and then uses |
665 |
-- 'genToRaw' to actually generate the function. |
666 |
genConstrToStr :: (String -> Q String) -> Name -> String -> Q [Dec] |
667 |
genConstrToStr trans_fun name fname = do |
668 |
cnames <- reifyConsNames name |
669 |
svalues <- mapM (liftM Left . trans_fun) cnames |
670 |
genToRaw ''String (mkName fname) name $ zip cnames svalues |
671 |
|
672 |
-- | Constructor-to-string for OpCode. |
673 |
genOpID :: Name -> String -> Q [Dec] |
674 |
genOpID = genConstrToStr (return . deCamelCase) |
675 |
|
676 |
-- | Strips @Op@ from the constructor name, converts to lower-case |
677 |
-- and adds a given prefix. |
678 |
genOpLowerStrip :: String -> Name -> String -> Q [Dec] |
679 |
genOpLowerStrip prefix = |
680 |
genConstrToStr (liftM ((prefix ++) . map toLower . deCamelCase) |
681 |
. stripPrefixM "Op") |
682 |
where |
683 |
stripPrefixM :: String -> String -> Q String |
684 |
stripPrefixM pfx s = maybe (fail $ s ++ " doesn't start with " ++ pfx) |
685 |
return |
686 |
$ stripPrefix pfx s |
687 |
|
688 |
-- | Builds a list with all defined constructor names for a type. |
689 |
-- |
690 |
-- @ |
691 |
-- vstr :: String |
692 |
-- vstr = [...] |
693 |
-- @ |
694 |
-- |
695 |
-- Where the actual values of the string are the constructor names |
696 |
-- mapped via @trans_fun@. |
697 |
genAllConstr :: (String -> String) -> Name -> String -> Q [Dec] |
698 |
genAllConstr trans_fun name vstr = do |
699 |
cnames <- reifyConsNames name |
700 |
let svalues = sort $ map trans_fun cnames |
701 |
vname = mkName vstr |
702 |
sig = SigD vname (AppT ListT (ConT ''String)) |
703 |
body = NormalB (ListE (map (LitE . StringL) svalues)) |
704 |
return $ [sig, ValD (VarP vname) body []] |
705 |
|
706 |
-- | Generates a list of all defined opcode IDs. |
707 |
genAllOpIDs :: Name -> String -> Q [Dec] |
708 |
genAllOpIDs = genAllConstr deCamelCase |
709 |
|
710 |
-- | OpCode parameter (field) type. |
711 |
type OpParam = (String, Q Type, Q Exp) |
712 |
|
713 |
-- * Python code generation |
714 |
|
715 |
data OpCodeField = OpCodeField { ocfName :: String |
716 |
, ocfType :: PyType |
717 |
, ocfDefl :: Maybe PyValueEx |
718 |
, ocfDoc :: String |
719 |
} |
720 |
|
721 |
-- | Transfers opcode data between the opcode description (through |
722 |
-- @genOpCode@) and the Python code generation functions. |
723 |
data OpCodeDescriptor = OpCodeDescriptor { ocdName :: String |
724 |
, ocdType :: PyType |
725 |
, ocdDoc :: String |
726 |
, ocdFields :: [OpCodeField] |
727 |
, ocdDescr :: String |
728 |
} |
729 |
|
730 |
-- | Optionally encapsulates default values in @PyValueEx@. |
731 |
-- |
732 |
-- @maybeApp exp typ@ returns a quoted expression that encapsulates |
733 |
-- the default value @exp@ of an opcode parameter cast to @typ@ in a |
734 |
-- @PyValueEx@, if @exp@ is @Just@. Otherwise, it returns a quoted |
735 |
-- expression with @Nothing@. |
736 |
maybeApp :: Maybe (Q Exp) -> Q Type -> Q Exp |
737 |
maybeApp Nothing _ = |
738 |
[| Nothing |] |
739 |
|
740 |
maybeApp (Just expr) typ = |
741 |
[| Just ($(conE (mkName "PyValueEx")) ($expr :: $typ)) |] |
742 |
|
743 |
-- | Generates a Python type according to whether the field is |
744 |
-- optional. |
745 |
-- |
746 |
-- The type of created expression is PyType. |
747 |
genPyType' :: OptionalType -> Q Type -> Q PyType |
748 |
genPyType' opt typ = typ >>= pyOptionalType (opt /= NotOptional) |
749 |
|
750 |
-- | Generates Python types from opcode parameters. |
751 |
genPyType :: Field -> Q PyType |
752 |
genPyType f = genPyType' (fieldIsOptional f) (fieldType f) |
753 |
|
754 |
-- | Generates Python default values from opcode parameters. |
755 |
genPyDefault :: Field -> Q Exp |
756 |
genPyDefault f = maybeApp (fieldDefault f) (fieldType f) |
757 |
|
758 |
pyField :: Field -> Q Exp |
759 |
pyField f = genPyType f >>= \t -> |
760 |
[| OpCodeField $(stringE (fieldName f)) |
761 |
t |
762 |
$(genPyDefault f) |
763 |
$(stringE (fieldDoc f)) |] |
764 |
|
765 |
-- | Generates a Haskell function call to "showPyClass" with the |
766 |
-- necessary information on how to build the Python class string. |
767 |
pyClass :: OpCodeConstructor -> Q Exp |
768 |
pyClass (consName, consType, consDoc, consFields, consDscField) = |
769 |
do let pyClassVar = varNameE "showPyClass" |
770 |
consName' = stringE consName |
771 |
consType' <- genPyType' NotOptional consType |
772 |
let consDoc' = stringE consDoc |
773 |
[| OpCodeDescriptor $consName' |
774 |
consType' |
775 |
$consDoc' |
776 |
$(listE $ map pyField consFields) |
777 |
consDscField |] |
778 |
|
779 |
-- | Generates a function called "pyClasses" that holds the list of |
780 |
-- all the opcode descriptors necessary for generating the Python |
781 |
-- opcodes. |
782 |
pyClasses :: [OpCodeConstructor] -> Q [Dec] |
783 |
pyClasses cons = |
784 |
do let name = mkName "pyClasses" |
785 |
sig = SigD name (AppT ListT (ConT ''OpCodeDescriptor)) |
786 |
fn <- FunD name <$> (:[]) <$> declClause cons |
787 |
return [sig, fn] |
788 |
where declClause c = |
789 |
clause [] (normalB (ListE <$> mapM pyClass c)) [] |
790 |
|
791 |
-- | Converts from an opcode constructor to a Luxi constructor. |
792 |
opcodeConsToLuxiCons :: (a, b, c, d, e) -> (a, d) |
793 |
opcodeConsToLuxiCons (x, _, _, y, _) = (x, y) |
794 |
|
795 |
-- | Generates the OpCode data type. |
796 |
-- |
797 |
-- This takes an opcode logical definition, and builds both the |
798 |
-- datatype and the JSON serialisation out of it. We can't use a |
799 |
-- generic serialisation since we need to be compatible with Ganeti's |
800 |
-- own, so we have a few quirks to work around. |
801 |
genOpCode :: String -- ^ Type name to use |
802 |
-> [OpCodeConstructor] -- ^ Constructor name and parameters |
803 |
-> Q [Dec] |
804 |
genOpCode name cons = do |
805 |
let tname = mkName name |
806 |
decl_d <- mapM (\(cname, _, _, fields, _) -> do |
807 |
-- we only need the type of the field, without Q |
808 |
fields' <- mapM (fieldTypeInfo "op") fields |
809 |
return $ RecC (mkName cname) fields') |
810 |
cons |
811 |
let declD = DataD [] tname [] decl_d [''Show, ''Eq] |
812 |
let (allfsig, allffn) = genAllOpFields "allOpFields" cons |
813 |
save_decs <- genSaveOpCode tname "saveOpCode" "toDictOpCode" |
814 |
(map opcodeConsToLuxiCons cons) saveConstructor True |
815 |
(loadsig, loadfn) <- genLoadOpCode cons |
816 |
pyDecls <- pyClasses cons |
817 |
return $ [declD, allfsig, allffn, loadsig, loadfn] ++ save_decs ++ pyDecls |
818 |
|
819 |
-- | Generates the function pattern returning the list of fields for a |
820 |
-- given constructor. |
821 |
genOpConsFields :: OpCodeConstructor -> Clause |
822 |
genOpConsFields (cname, _, _, fields, _) = |
823 |
let op_id = deCamelCase cname |
824 |
fvals = map (LitE . StringL) . sort . nub $ |
825 |
concatMap (\f -> fieldName f:fieldExtraKeys f) fields |
826 |
in Clause [LitP (StringL op_id)] (NormalB $ ListE fvals) [] |
827 |
|
828 |
-- | Generates a list of all fields of an opcode constructor. |
829 |
genAllOpFields :: String -- ^ Function name |
830 |
-> [OpCodeConstructor] -- ^ Object definition |
831 |
-> (Dec, Dec) |
832 |
genAllOpFields sname opdefs = |
833 |
let cclauses = map genOpConsFields opdefs |
834 |
other = Clause [WildP] (NormalB (ListE [])) [] |
835 |
fname = mkName sname |
836 |
sigt = AppT (AppT ArrowT (ConT ''String)) (AppT ListT (ConT ''String)) |
837 |
in (SigD fname sigt, FunD fname (cclauses++[other])) |
838 |
|
839 |
-- | Generates the \"save\" clause for an entire opcode constructor. |
840 |
-- |
841 |
-- This matches the opcode with variables named the same as the |
842 |
-- constructor fields (just so that the spliced in code looks nicer), |
843 |
-- and passes those name plus the parameter definition to 'saveObjectField'. |
844 |
saveConstructor :: LuxiConstructor -- ^ The constructor |
845 |
-> Q Clause -- ^ Resulting clause |
846 |
saveConstructor (sname, fields) = do |
847 |
let cname = mkName sname |
848 |
fnames <- mapM (newName . fieldVariable) fields |
849 |
let pat = conP cname (map varP fnames) |
850 |
let felems = zipWith saveObjectField fnames fields |
851 |
-- now build the OP_ID serialisation |
852 |
opid = [| [( $(stringE "OP_ID"), |
853 |
JSON.showJSON $(stringE . deCamelCase $ sname) )] |] |
854 |
flist = listE (opid:felems) |
855 |
-- and finally convert all this to a json object |
856 |
flist' = [| concat $flist |] |
857 |
clause [pat] (normalB flist') [] |
858 |
|
859 |
-- | Generates the main save opcode function. |
860 |
-- |
861 |
-- This builds a per-constructor match clause that contains the |
862 |
-- respective constructor-serialisation code. |
863 |
genSaveOpCode :: Name -- ^ Object ype |
864 |
-> String -- ^ To 'JSValue' function name |
865 |
-> String -- ^ To 'JSObject' function name |
866 |
-> [LuxiConstructor] -- ^ Object definition |
867 |
-> (LuxiConstructor -> Q Clause) -- ^ Constructor save fn |
868 |
-> Bool -- ^ Whether to generate |
869 |
-- obj or just a |
870 |
-- list\/tuple of values |
871 |
-> Q [Dec] |
872 |
genSaveOpCode tname jvalstr tdstr opdefs fn gen_object = do |
873 |
tdclauses <- mapM fn opdefs |
874 |
let typecon = ConT tname |
875 |
jvalname = mkName jvalstr |
876 |
jvalsig = AppT (AppT ArrowT typecon) (ConT ''JSON.JSValue) |
877 |
tdname = mkName tdstr |
878 |
tdsig <- [t| $(return typecon) -> [(String, JSON.JSValue)] |] |
879 |
jvalclause <- if gen_object |
880 |
then [| $makeObjE . $(varE tdname) |] |
881 |
else [| JSON.showJSON . map snd . $(varE tdname) |] |
882 |
return [ SigD tdname tdsig |
883 |
, FunD tdname tdclauses |
884 |
, SigD jvalname jvalsig |
885 |
, ValD (VarP jvalname) (NormalB jvalclause) []] |
886 |
|
887 |
-- | Generates load code for a single constructor of the opcode data type. |
888 |
loadConstructor :: Name -> (Field -> Q Exp) -> [Field] -> Q Exp |
889 |
loadConstructor name loadfn fields = do |
890 |
fnames <- mapM (newName . ("r_" ++) . fieldName) fields |
891 |
fexps <- mapM loadfn fields |
892 |
let fstmts = zipWith (BindS . VarP) fnames fexps |
893 |
cexp = foldl (\accu fn -> AppE accu (VarE fn)) (ConE name) fnames |
894 |
retstmt = [NoBindS (AppE (VarE 'return) cexp)] |
895 |
-- FIXME: should we require an empty dict for an empty type? |
896 |
-- this allows any JSValue right now |
897 |
return $ DoE (fstmts ++ retstmt) |
898 |
|
899 |
-- | Generates load code for a single constructor of the opcode data type. |
900 |
loadOpConstructor :: OpCodeConstructor -> Q Exp |
901 |
loadOpConstructor (sname, _, _, fields, _) = |
902 |
loadConstructor (mkName sname) (loadObjectField fields) fields |
903 |
|
904 |
-- | Generates the loadOpCode function. |
905 |
genLoadOpCode :: [OpCodeConstructor] -> Q (Dec, Dec) |
906 |
genLoadOpCode opdefs = do |
907 |
let fname = mkName "loadOpCode" |
908 |
arg1 = mkName "v" |
909 |
objname = objVarName |
910 |
opid = mkName "op_id" |
911 |
st1 <- bindS (varP objname) [| liftM JSON.fromJSObject |
912 |
(JSON.readJSON $(varE arg1)) |] |
913 |
st2 <- bindS (varP opid) [| $fromObjE $(varE objname) $(stringE "OP_ID") |] |
914 |
-- the match results (per-constructor blocks) |
915 |
mexps <- mapM loadOpConstructor opdefs |
916 |
fails <- [| fail $ "Unknown opcode " ++ $(varE opid) |] |
917 |
let mpats = map (\(me, (consName, _, _, _, _)) -> |
918 |
let mp = LitP . StringL . deCamelCase $ consName |
919 |
in Match mp (NormalB me) [] |
920 |
) $ zip mexps opdefs |
921 |
defmatch = Match WildP (NormalB fails) [] |
922 |
cst = NoBindS $ CaseE (VarE opid) $ mpats++[defmatch] |
923 |
body = DoE [st1, st2, cst] |
924 |
sigt <- [t| JSON.JSValue -> JSON.Result $(conT (mkName "OpCode")) |] |
925 |
return $ (SigD fname sigt, FunD fname [Clause [VarP arg1] (NormalB body) []]) |
926 |
|
927 |
-- * Template code for luxi |
928 |
|
929 |
-- | Constructor-to-string for LuxiOp. |
930 |
genStrOfOp :: Name -> String -> Q [Dec] |
931 |
genStrOfOp = genConstrToStr return |
932 |
|
933 |
-- | Constructor-to-string for MsgKeys. |
934 |
genStrOfKey :: Name -> String -> Q [Dec] |
935 |
genStrOfKey = genConstrToStr (return . ensureLower) |
936 |
|
937 |
-- | Generates the LuxiOp data type. |
938 |
-- |
939 |
-- This takes a Luxi operation definition and builds both the |
940 |
-- datatype and the function transforming the arguments to JSON. |
941 |
-- We can't use anything less generic, because the way different |
942 |
-- operations are serialized differs on both parameter- and top-level. |
943 |
-- |
944 |
-- There are two things to be defined for each parameter: |
945 |
-- |
946 |
-- * name |
947 |
-- |
948 |
-- * type |
949 |
-- |
950 |
genLuxiOp :: String -> [LuxiConstructor] -> Q [Dec] |
951 |
genLuxiOp name cons = do |
952 |
let tname = mkName name |
953 |
decl_d <- mapM (\(cname, fields) -> do |
954 |
-- we only need the type of the field, without Q |
955 |
fields' <- mapM actualFieldType fields |
956 |
let fields'' = zip (repeat NotStrict) fields' |
957 |
return $ NormalC (mkName cname) fields'') |
958 |
cons |
959 |
let declD = DataD [] (mkName name) [] decl_d [''Show, ''Eq] |
960 |
save_decs <- genSaveOpCode tname "opToArgs" "opToDict" |
961 |
cons saveLuxiConstructor False |
962 |
req_defs <- declareSADT "LuxiReq" . |
963 |
map (\(str, _) -> ("Req" ++ str, mkName ("luxiReq" ++ str))) $ |
964 |
cons |
965 |
return $ declD:save_decs ++ req_defs |
966 |
|
967 |
-- | Generates the \"save\" clause for entire LuxiOp constructor. |
968 |
saveLuxiConstructor :: LuxiConstructor -> Q Clause |
969 |
saveLuxiConstructor (sname, fields) = do |
970 |
let cname = mkName sname |
971 |
fnames <- mapM (newName . fieldVariable) fields |
972 |
let pat = conP cname (map varP fnames) |
973 |
let felems = zipWith saveObjectField fnames fields |
974 |
flist = [| concat $(listE felems) |] |
975 |
clause [pat] (normalB flist) [] |
976 |
|
977 |
-- * "Objects" functionality |
978 |
|
979 |
-- | Extract the field's declaration from a Field structure. |
980 |
fieldTypeInfo :: String -> Field -> Q (Name, Strict, Type) |
981 |
fieldTypeInfo field_pfx fd = do |
982 |
t <- actualFieldType fd |
983 |
let n = mkName . (field_pfx ++) . fieldRecordName $ fd |
984 |
return (n, NotStrict, t) |
985 |
|
986 |
-- | Build an object declaration. |
987 |
buildObject :: String -> String -> [Field] -> Q [Dec] |
988 |
buildObject sname field_pfx fields = do |
989 |
when (any ((==) AndRestArguments . fieldIsOptional) |
990 |
. drop 1 $ reverse fields) |
991 |
$ fail "Objects may have only one AndRestArguments field,\ |
992 |
\ and it must be the last one." |
993 |
let name = mkName sname |
994 |
fields_d <- mapM (fieldTypeInfo field_pfx) fields |
995 |
let decl_d = RecC name fields_d |
996 |
let declD = DataD [] name [] [decl_d] [''Show, ''Eq] |
997 |
ser_decls <- buildObjectSerialisation sname fields |
998 |
return $ declD:ser_decls |
999 |
|
1000 |
-- | Generates an object definition: data type and its JSON instance. |
1001 |
buildObjectSerialisation :: String -> [Field] -> Q [Dec] |
1002 |
buildObjectSerialisation sname fields = do |
1003 |
let name = mkName sname |
1004 |
dictdecls <- genDictObject saveObjectField |
1005 |
(loadObjectField fields) sname fields |
1006 |
savedecls <- genSaveObject sname |
1007 |
(loadsig, loadfn) <- genLoadObject sname |
1008 |
shjson <- objectShowJSON sname |
1009 |
rdjson <- objectReadJSON sname |
1010 |
let instdecl = InstanceD [] (AppT (ConT ''JSON.JSON) (ConT name)) |
1011 |
[rdjson, shjson] |
1012 |
return $ dictdecls ++ savedecls ++ [loadsig, loadfn, instdecl] |
1013 |
|
1014 |
-- | An internal name used for naming variables that hold the entire |
1015 |
-- object of type @[(String,JSValue)]@. |
1016 |
objVarName :: Name |
1017 |
objVarName = mkName "_o" |
1018 |
|
1019 |
-- | Provides a default 'toJSArray' for 'ArrayObject' instance using its |
1020 |
-- existing 'DictObject' instance. The keys are serialized in the order |
1021 |
-- they're declared. The list must contain all keys possibly generated by |
1022 |
-- 'toDict'. |
1023 |
defaultToJSArray :: (DictObject a) => [String] -> a -> [JSON.JSValue] |
1024 |
defaultToJSArray keys o = |
1025 |
let m = M.fromList $ toDict o |
1026 |
in map (fromMaybe JSON.JSNull . flip M.lookup m) keys |
1027 |
|
1028 |
-- | Provides a default 'fromJSArray' for 'ArrayObject' instance using its |
1029 |
-- existing 'DictObject' instance. The fields are deserialized in the order |
1030 |
-- they're declared. |
1031 |
defaultFromJSArray :: (DictObject a) |
1032 |
=> [String] -> [JSON.JSValue] -> JSON.Result a |
1033 |
defaultFromJSArray keys xs = do |
1034 |
let xslen = length xs |
1035 |
explen = length keys |
1036 |
unless (xslen == explen) (fail $ "Expected " ++ show explen |
1037 |
++ " arguments, got " ++ show xslen) |
1038 |
fromDict $ zip keys xs |
1039 |
|
1040 |
-- | Generates an additional 'ArrayObject' instance using its |
1041 |
-- existing 'DictObject' instance. |
1042 |
-- |
1043 |
-- See 'defaultToJSArray' and 'defaultFromJSArray'. |
1044 |
genArrayObjectInstance :: Name -> [Field] -> Q Dec |
1045 |
genArrayObjectInstance name fields = do |
1046 |
let fnames = concatMap (liftA2 (:) fieldName fieldExtraKeys) fields |
1047 |
instanceD (return []) (appT (conT ''ArrayObject) (conT name)) |
1048 |
[ valD (varP 'toJSArray) (normalB [| defaultToJSArray $(lift fnames) |]) [] |
1049 |
, valD (varP 'fromJSArray) (normalB [| defaultFromJSArray fnames |]) [] |
1050 |
] |
1051 |
|
1052 |
-- | Generates 'DictObject' instance. |
1053 |
genDictObject :: (Name -> Field -> Q Exp) -- ^ a saving function |
1054 |
-> (Field -> Q Exp) -- ^ a loading function |
1055 |
-> String -- ^ an object name |
1056 |
-> [Field] -- ^ a list of fields |
1057 |
-> Q [Dec] |
1058 |
genDictObject save_fn load_fn sname fields = do |
1059 |
let name = mkName sname |
1060 |
-- toDict |
1061 |
fnames <- mapM (newName . fieldVariable) fields |
1062 |
let pat = conP name (map varP fnames) |
1063 |
tdexp = [| concat $(listE $ zipWith save_fn fnames fields) |] |
1064 |
tdclause <- clause [pat] (normalB tdexp) [] |
1065 |
-- fromDict |
1066 |
fdexp <- loadConstructor name load_fn fields |
1067 |
let fdclause = Clause [VarP objVarName] (NormalB fdexp) [] |
1068 |
-- the ArrayObject instance generated from DictObject |
1069 |
arrdec <- genArrayObjectInstance name fields |
1070 |
-- the final instance |
1071 |
return $ [InstanceD [] (AppT (ConT ''DictObject) (ConT name)) |
1072 |
[ FunD 'toDict [tdclause] |
1073 |
, FunD 'fromDict [fdclause] |
1074 |
]] |
1075 |
++ [arrdec] |
1076 |
|
1077 |
-- | Generates the save object functionality. |
1078 |
genSaveObject :: String -> Q [Dec] |
1079 |
genSaveObject sname = do |
1080 |
let fname = mkName ("save" ++ sname) |
1081 |
sigt <- [t| $(conT $ mkName sname) -> JSON.JSValue |] |
1082 |
cclause <- [| $makeObjE . $(varE $ 'toDict) |] |
1083 |
return [SigD fname sigt, ValD (VarP fname) (NormalB cclause) []] |
1084 |
|
1085 |
-- | Generates the code for saving an object's field, handling the |
1086 |
-- various types of fields that we have. |
1087 |
saveObjectField :: Name -> Field -> Q Exp |
1088 |
saveObjectField fvar field = |
1089 |
let formatFn = fromMaybe [| JSON.showJSON &&& (const []) |] $ |
1090 |
fieldShow field |
1091 |
formatCode v = [| let (actual, extra) = $formatFn $(v) |
1092 |
in ($nameE, actual) : extra |] |
1093 |
in case fieldIsOptional field of |
1094 |
OptionalOmitNull -> [| case $(fvarE) of |
1095 |
Nothing -> [] |
1096 |
Just v -> $(formatCode [| v |]) |
1097 |
|] |
1098 |
OptionalSerializeNull -> [| case $(fvarE) of |
1099 |
Nothing -> [( $nameE, JSON.JSNull )] |
1100 |
Just v -> $(formatCode [| v |]) |
1101 |
|] |
1102 |
NotOptional -> formatCode fvarE |
1103 |
AndRestArguments -> [| M.toList $(varE fvar) |] |
1104 |
where nameE = stringE (fieldName field) |
1105 |
fvarE = varE fvar |
1106 |
|
1107 |
-- | Generates the showJSON clause for a given object name. |
1108 |
objectShowJSON :: String -> Q Dec |
1109 |
objectShowJSON name = do |
1110 |
body <- [| JSON.showJSON . $(varE . mkName $ "save" ++ name) |] |
1111 |
return $ FunD 'JSON.showJSON [Clause [] (NormalB body) []] |
1112 |
|
1113 |
-- | Generates the load object functionality. |
1114 |
genLoadObject :: String -> Q (Dec, Dec) |
1115 |
genLoadObject sname = do |
1116 |
let fname = mkName $ "load" ++ sname |
1117 |
sigt <- [t| JSON.JSValue -> JSON.Result $(conT $ mkName sname) |] |
1118 |
cclause <- [| fromDict <=< liftM JSON.fromJSObject . JSON.readJSON |] |
1119 |
return $ (SigD fname sigt, |
1120 |
FunD fname [Clause [] (NormalB cclause) []]) |
1121 |
|
1122 |
-- | Generates code for loading an object's field. |
1123 |
loadObjectField :: [Field] -> Field -> Q Exp |
1124 |
loadObjectField allFields field = do |
1125 |
let name = fieldVariable field |
1126 |
names = map fieldVariable allFields |
1127 |
otherNames = listE . map stringE $ names \\ [name] |
1128 |
-- these are used in all patterns below |
1129 |
let objvar = varE objVarName |
1130 |
objfield = stringE (fieldName field) |
1131 |
case (fieldDefault field, fieldIsOptional field) of |
1132 |
-- Only non-optional fields without defaults must have a value; |
1133 |
-- we treat both optional types the same, since |
1134 |
-- 'maybeFromObj' can deal with both missing and null values |
1135 |
-- appropriately (the same) |
1136 |
(Nothing, NotOptional) -> |
1137 |
loadFn field [| fromObj $objvar $objfield |] objvar |
1138 |
-- AndRestArguments need not to be parsed at all, |
1139 |
-- they're just extracted from the list of other fields. |
1140 |
(Nothing, AndRestArguments) -> |
1141 |
[| return . M.fromList |
1142 |
$ filter (not . (`elem` $otherNames) . fst) $objvar |] |
1143 |
_ -> loadFnOpt field [| maybeFromObj $objvar $objfield |] objvar |
1144 |
|
1145 |
-- | Builds the readJSON instance for a given object name. |
1146 |
objectReadJSON :: String -> Q Dec |
1147 |
objectReadJSON name = do |
1148 |
let s = mkName "s" |
1149 |
body <- [| $(varE . mkName $ "load" ++ name) =<< |
1150 |
readJSONWithDesc $(stringE name) False $(varE s) |] |
1151 |
return $ FunD 'JSON.readJSON [Clause [VarP s] (NormalB body) []] |
1152 |
|
1153 |
-- * Inheritable parameter tables implementation |
1154 |
|
1155 |
-- | Compute parameter type names. |
1156 |
paramTypeNames :: String -> (String, String) |
1157 |
paramTypeNames root = ("Filled" ++ root ++ "Params", |
1158 |
"Partial" ++ root ++ "Params") |
1159 |
|
1160 |
-- | Compute information about the type of a parameter field. |
1161 |
paramFieldTypeInfo :: String -> Field -> Q (Name, Strict, Type) |
1162 |
paramFieldTypeInfo field_pfx fd = do |
1163 |
t <- actualFieldType fd |
1164 |
let n = mkName . (++ "P") . (field_pfx ++) . |
1165 |
fieldRecordName $ fd |
1166 |
return (n, NotStrict, AppT (ConT ''Maybe) t) |
1167 |
|
1168 |
-- | Build a parameter declaration. |
1169 |
-- |
1170 |
-- This function builds two different data structures: a /filled/ one, |
1171 |
-- in which all fields are required, and a /partial/ one, in which all |
1172 |
-- fields are optional. Due to the current record syntax issues, the |
1173 |
-- fields need to be named differrently for the two structures, so the |
1174 |
-- partial ones get a /P/ suffix. |
1175 |
buildParam :: String -> String -> [Field] -> Q [Dec] |
1176 |
buildParam sname field_pfx fields = do |
1177 |
let (sname_f, sname_p) = paramTypeNames sname |
1178 |
name_f = mkName sname_f |
1179 |
name_p = mkName sname_p |
1180 |
fields_f <- mapM (fieldTypeInfo field_pfx) fields |
1181 |
fields_p <- mapM (paramFieldTypeInfo field_pfx) fields |
1182 |
let decl_f = RecC name_f fields_f |
1183 |
decl_p = RecC name_p fields_p |
1184 |
let declF = DataD [] name_f [] [decl_f] [''Show, ''Eq] |
1185 |
declP = DataD [] name_p [] [decl_p] [''Show, ''Eq] |
1186 |
ser_decls_f <- buildObjectSerialisation sname_f fields |
1187 |
ser_decls_p <- buildPParamSerialisation sname_p fields |
1188 |
fill_decls <- fillParam sname field_pfx fields |
1189 |
return $ [declF, declP] ++ ser_decls_f ++ ser_decls_p ++ fill_decls ++ |
1190 |
buildParamAllFields sname fields |
1191 |
|
1192 |
-- | Builds a list of all fields of a parameter. |
1193 |
buildParamAllFields :: String -> [Field] -> [Dec] |
1194 |
buildParamAllFields sname fields = |
1195 |
let vname = mkName ("all" ++ sname ++ "ParamFields") |
1196 |
sig = SigD vname (AppT ListT (ConT ''String)) |
1197 |
val = ListE $ map (LitE . StringL . fieldName) fields |
1198 |
in [sig, ValD (VarP vname) (NormalB val) []] |
1199 |
|
1200 |
-- | Generates the serialisation for a partial parameter. |
1201 |
buildPParamSerialisation :: String -> [Field] -> Q [Dec] |
1202 |
buildPParamSerialisation sname fields = do |
1203 |
let name = mkName sname |
1204 |
dictdecls <- genDictObject savePParamField loadPParamField sname fields |
1205 |
savedecls <- genSaveObject sname |
1206 |
(loadsig, loadfn) <- genLoadObject sname |
1207 |
shjson <- objectShowJSON sname |
1208 |
rdjson <- objectReadJSON sname |
1209 |
let instdecl = InstanceD [] (AppT (ConT ''JSON.JSON) (ConT name)) |
1210 |
[rdjson, shjson] |
1211 |
return $ dictdecls ++ savedecls ++ [loadsig, loadfn, instdecl] |
1212 |
|
1213 |
-- | Generates code to save an optional parameter field. |
1214 |
savePParamField :: Name -> Field -> Q Exp |
1215 |
savePParamField fvar field = do |
1216 |
checkNonOptDef field |
1217 |
let actualVal = mkName "v" |
1218 |
normalexpr <- saveObjectField actualVal field |
1219 |
-- we have to construct the block here manually, because we can't |
1220 |
-- splice-in-splice |
1221 |
return $ CaseE (VarE fvar) [ Match (ConP 'Nothing []) |
1222 |
(NormalB (ConE '[])) [] |
1223 |
, Match (ConP 'Just [VarP actualVal]) |
1224 |
(NormalB normalexpr) [] |
1225 |
] |
1226 |
|
1227 |
-- | Generates code to load an optional parameter field. |
1228 |
loadPParamField :: Field -> Q Exp |
1229 |
loadPParamField field = do |
1230 |
checkNonOptDef field |
1231 |
let name = fieldName field |
1232 |
-- these are used in all patterns below |
1233 |
let objvar = varE objVarName |
1234 |
objfield = stringE name |
1235 |
loadexp = [| $(varE 'maybeFromObj) $objvar $objfield |] |
1236 |
loadFnOpt field loadexp objvar |
1237 |
|
1238 |
-- | Builds a simple declaration of type @n_x = fromMaybe f_x p_x@. |
1239 |
buildFromMaybe :: String -> Q Dec |
1240 |
buildFromMaybe fname = |
1241 |
valD (varP (mkName $ "n_" ++ fname)) |
1242 |
(normalB [| $(varE 'fromMaybe) |
1243 |
$(varNameE $ "f_" ++ fname) |
1244 |
$(varNameE $ "p_" ++ fname) |]) [] |
1245 |
|
1246 |
-- | Builds a function that executes the filling of partial parameter |
1247 |
-- from a full copy (similar to Python's fillDict). |
1248 |
fillParam :: String -> String -> [Field] -> Q [Dec] |
1249 |
fillParam sname field_pfx fields = do |
1250 |
let fnames = map (\fd -> field_pfx ++ fieldRecordName fd) fields |
1251 |
(sname_f, sname_p) = paramTypeNames sname |
1252 |
oname_f = "fobj" |
1253 |
oname_p = "pobj" |
1254 |
name_f = mkName sname_f |
1255 |
name_p = mkName sname_p |
1256 |
fun_name = mkName $ "fill" ++ sname ++ "Params" |
1257 |
le_full = ValD (ConP name_f (map (VarP . mkName . ("f_" ++)) fnames)) |
1258 |
(NormalB . VarE . mkName $ oname_f) [] |
1259 |
le_part = ValD (ConP name_p (map (VarP . mkName . ("p_" ++)) fnames)) |
1260 |
(NormalB . VarE . mkName $ oname_p) [] |
1261 |
obj_new = foldl (\accu vname -> AppE accu (VarE vname)) (ConE name_f) |
1262 |
$ map (mkName . ("n_" ++)) fnames |
1263 |
le_new <- mapM buildFromMaybe fnames |
1264 |
funt <- [t| $(conT name_f) -> $(conT name_p) -> $(conT name_f) |] |
1265 |
let sig = SigD fun_name funt |
1266 |
fclause = Clause [VarP (mkName oname_f), VarP (mkName oname_p)] |
1267 |
(NormalB $ LetE (le_full:le_part:le_new) obj_new) [] |
1268 |
fun = FunD fun_name [fclause] |
1269 |
return [sig, fun] |
1270 |
|
1271 |
-- * Template code for exceptions |
1272 |
|
1273 |
-- | Exception simple error message field. |
1274 |
excErrMsg :: (String, Q Type) |
1275 |
excErrMsg = ("errMsg", [t| String |]) |
1276 |
|
1277 |
-- | Builds an exception type definition. |
1278 |
genException :: String -- ^ Name of new type |
1279 |
-> SimpleObject -- ^ Constructor name and parameters |
1280 |
-> Q [Dec] |
1281 |
genException name cons = do |
1282 |
let tname = mkName name |
1283 |
declD <- buildSimpleCons tname cons |
1284 |
(savesig, savefn) <- genSaveSimpleObj tname ("save" ++ name) cons $ |
1285 |
uncurry saveExcCons |
1286 |
(loadsig, loadfn) <- genLoadExc tname ("load" ++ name) cons |
1287 |
return [declD, loadsig, loadfn, savesig, savefn] |
1288 |
|
1289 |
-- | Generates the \"save\" clause for an entire exception constructor. |
1290 |
-- |
1291 |
-- This matches the exception with variables named the same as the |
1292 |
-- constructor fields (just so that the spliced in code looks nicer), |
1293 |
-- and calls showJSON on it. |
1294 |
saveExcCons :: String -- ^ The constructor name |
1295 |
-> [SimpleField] -- ^ The parameter definitions for this |
1296 |
-- constructor |
1297 |
-> Q Clause -- ^ Resulting clause |
1298 |
saveExcCons sname fields = do |
1299 |
let cname = mkName sname |
1300 |
fnames <- mapM (newName . fst) fields |
1301 |
let pat = conP cname (map varP fnames) |
1302 |
felems = if null fnames |
1303 |
then conE '() -- otherwise, empty list has no type |
1304 |
else listE $ map (\f -> [| JSON.showJSON $(varE f) |]) fnames |
1305 |
let tup = tupE [ litE (stringL sname), felems ] |
1306 |
clause [pat] (normalB [| JSON.showJSON $tup |]) [] |
1307 |
|
1308 |
-- | Generates load code for a single constructor of an exception. |
1309 |
-- |
1310 |
-- Generates the code (if there's only one argument, we will use a |
1311 |
-- list, not a tuple: |
1312 |
-- |
1313 |
-- @ |
1314 |
-- do |
1315 |
-- (x1, x2, ...) <- readJSON args |
1316 |
-- return $ Cons x1 x2 ... |
1317 |
-- @ |
1318 |
loadExcConstructor :: Name -> String -> [SimpleField] -> Q Exp |
1319 |
loadExcConstructor inname sname fields = do |
1320 |
let name = mkName sname |
1321 |
f_names <- mapM (newName . fst) fields |
1322 |
let read_args = AppE (VarE 'JSON.readJSON) (VarE inname) |
1323 |
let binds = case f_names of |
1324 |
[x] -> BindS (ListP [VarP x]) |
1325 |
_ -> BindS (TupP (map VarP f_names)) |
1326 |
cval = foldl (\accu fn -> AppE accu (VarE fn)) (ConE name) f_names |
1327 |
return $ DoE [binds read_args, NoBindS (AppE (VarE 'return) cval)] |
1328 |
|
1329 |
{-| Generates the loadException function. |
1330 |
|
1331 |
This generates a quite complicated function, along the lines of: |
1332 |
|
1333 |
@ |
1334 |
loadFn (JSArray [JSString name, args]) = case name of |
1335 |
"A1" -> do |
1336 |
(x1, x2, ...) <- readJSON args |
1337 |
return $ A1 x1 x2 ... |
1338 |
"a2" -> ... |
1339 |
s -> fail $ "Unknown exception" ++ s |
1340 |
loadFn v = fail $ "Expected array but got " ++ show v |
1341 |
@ |
1342 |
-} |
1343 |
genLoadExc :: Name -> String -> SimpleObject -> Q (Dec, Dec) |
1344 |
genLoadExc tname sname opdefs = do |
1345 |
let fname = mkName sname |
1346 |
exc_name <- newName "name" |
1347 |
exc_args <- newName "args" |
1348 |
exc_else <- newName "s" |
1349 |
arg_else <- newName "v" |
1350 |
fails <- [| fail $ "Unknown exception '" ++ $(varE exc_else) ++ "'" |] |
1351 |
-- default match for unknown exception name |
1352 |
let defmatch = Match (VarP exc_else) (NormalB fails) [] |
1353 |
-- the match results (per-constructor blocks) |
1354 |
str_matches <- |
1355 |
mapM (\(s, params) -> do |
1356 |
body_exp <- loadExcConstructor exc_args s params |
1357 |
return $ Match (LitP (StringL s)) (NormalB body_exp) []) |
1358 |
opdefs |
1359 |
-- the first function clause; we can't use [| |] due to TH |
1360 |
-- limitations, so we have to build the AST by hand |
1361 |
let clause1 = Clause [ConP 'JSON.JSArray |
1362 |
[ListP [ConP 'JSON.JSString [VarP exc_name], |
1363 |
VarP exc_args]]] |
1364 |
(NormalB (CaseE (AppE (VarE 'JSON.fromJSString) |
1365 |
(VarE exc_name)) |
1366 |
(str_matches ++ [defmatch]))) [] |
1367 |
-- the fail expression for the second function clause |
1368 |
fail_type <- [| fail $ "Invalid exception: expected '(string, [args])' " ++ |
1369 |
" but got " ++ show (pp_value $(varE arg_else)) ++ "'" |
1370 |
|] |
1371 |
-- the second function clause |
1372 |
let clause2 = Clause [VarP arg_else] (NormalB fail_type) [] |
1373 |
sigt <- [t| JSON.JSValue -> JSON.Result $(conT tname) |] |
1374 |
return $ (SigD fname sigt, FunD fname [clause1, clause2]) |