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{-# LANGUAGE ExistentialQuantification, 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 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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, declareIADT |
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, makeJSONInstance |
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, genOpID |
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, genAllConstr |
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, genAllOpIDs |
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, PyValue(..) |
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, PyValueEx(..) |
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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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, 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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, genException |
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, excErrMsg |
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) where |
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|
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import Control.Monad (liftM) |
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import Data.Char |
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import Data.List |
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import qualified Data.Set as Set |
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import Language.Haskell.TH |
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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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|
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import Data.Maybe |
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import Data.Functor ((<$>)) |
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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 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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|
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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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deriving (Show, Eq) |
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|
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-- | Serialised field data type. |
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data Field = Field { fieldName :: String |
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, fieldType :: Q Type |
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, fieldRead :: Maybe (Q Exp) |
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, fieldShow :: Maybe (Q Exp) |
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, fieldExtraKeys :: [String] |
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, fieldDefault :: Maybe (Q Exp) |
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, fieldConstr :: Maybe String |
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, fieldIsOptional :: OptionalType |
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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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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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-- | 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 /= NotOptional = [t| Maybe $t |] |
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| otherwise = 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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-- | 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 { fieldRead = Just readfn }) expr o = [| $expr >>= $readfn $o |] |
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loadFn _ expr _ = expr |
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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 = |
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[ defaultField [| 0::Double |] $ simpleField "ctime" [t| Double |] |
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, defaultField [| 0::Double |] $ simpleField "mtime" [t| Double |] |
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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, 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 |
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clauses <- mapM (\(c, v) -> do |
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-- the clause match condition |
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g <- normalG [| $varpe == $(varE v) |] |
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-- the clause result |
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r <- [| return $(conE (mkName c)) |] |
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return (g, r)) constructors |
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-- the otherwise clause (fallback) |
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oth_clause <- do |
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g <- normalG [| otherwise |] |
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r <- [|fail ("Invalid string value for type " ++ |
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$(litE (stringL (nameBase tname))) ++ ": " ++ show $varpe) |] |
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return (g, r) |
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let fun = FunD fname [Clause [VarP varp] |
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(GuardedB (clauses++[oth_clause])) []] |
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return [SigD fname sigt, fun] |
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|
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-- | Generates a data type from a given raw format. |
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-- |
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-- The format is expected to multiline. The first line contains the |
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-- type name, and the rest of the lines must contain two words: the |
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-- constructor name and then the string representation of the |
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-- respective constructor. |
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-- |
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-- The function will generate the data type declaration, and then two |
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-- functions: |
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-- |
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-- * /name/ToRaw, which converts the type to a raw type |
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-- |
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-- * /name/FromRaw, which (monadically) converts from a raw type to the type |
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-- |
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-- Note that this is basically just a custom show\/read instance, |
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-- nothing else. |
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declareADT :: Name -> String -> [(String, Name)] -> Q [Dec] |
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declareADT traw sname cons = do |
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let name = mkName sname |
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ddecl = strADTDecl name (map fst cons) |
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-- process cons in the format expected by genToRaw |
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cons' = map (\(a, b) -> (a, Right b)) cons |
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toraw <- genToRaw traw (toRawName sname) name cons' |
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fromraw <- genFromRaw traw (fromRawName sname) name cons |
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return $ ddecl:toraw ++ fromraw |
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|
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declareIADT :: String -> [(String, Name)] -> Q [Dec] |
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declareIADT = declareADT ''Int |
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|
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declareSADT :: String -> [(String, Name)] -> Q [Dec] |
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declareSADT = declareADT ''String |
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|
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-- | Creates the showJSON member of a JSON instance declaration. |
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-- |
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-- This will create what is the equivalent of: |
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-- |
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-- @ |
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-- showJSON = showJSON . /name/ToRaw |
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-- @ |
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-- |
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-- in an instance JSON /name/ declaration |
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genShowJSON :: String -> Q Dec |
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genShowJSON name = do |
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body <- [| JSON.showJSON . $(varE (toRawName name)) |] |
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return $ FunD 'JSON.showJSON [Clause [] (NormalB body) []] |
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|
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-- | Creates the readJSON member of a JSON instance declaration. |
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-- |
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-- This will create what is the equivalent of: |
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-- |
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-- @ |
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-- readJSON s = case readJSON s of |
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-- Ok s' -> /name/FromRaw s' |
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-- Error e -> Error /description/ |
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-- @ |
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-- |
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-- in an instance JSON /name/ declaration |
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genReadJSON :: String -> Q Dec |
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genReadJSON name = do |
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let s = mkName "s" |
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body <- [| case JSON.readJSON $(varE s) of |
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JSON.Ok s' -> $(varE (fromRawName name)) s' |
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JSON.Error e -> |
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JSON.Error $ "Can't parse raw value for type " ++ |
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$(stringE name) ++ ": " ++ e ++ " from " ++ |
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show $(varE s) |
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|] |
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return $ FunD 'JSON.readJSON [Clause [VarP s] (NormalB body) []] |
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|
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-- | Generates a JSON instance for a given type. |
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-- |
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-- This assumes that the /name/ToRaw and /name/FromRaw functions |
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-- have been defined as by the 'declareSADT' function. |
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makeJSONInstance :: Name -> Q [Dec] |
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makeJSONInstance name = do |
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let base = nameBase name |
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showJ <- genShowJSON base |
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readJ <- genReadJSON base |
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return [InstanceD [] (AppT (ConT ''JSON.JSON) (ConT name)) [readJ,showJ]] |
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|
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-- * Template code for opcodes |
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|
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-- | Transforms a CamelCase string into an_underscore_based_one. |
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deCamelCase :: String -> String |
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deCamelCase = |
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intercalate "_" . map (map toUpper) . groupBy (\_ b -> not $ isUpper b) |
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|
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-- | Transform an underscore_name into a CamelCase one. |
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camelCase :: String -> String |
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camelCase = concatMap (ensureUpper . drop 1) . |
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groupBy (\_ b -> b /= '_' && b /= '-') . ('_':) |
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|
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-- | Computes the name of a given constructor. |
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constructorName :: Con -> Q Name |
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constructorName (NormalC name _) = return name |
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constructorName (RecC name _) = return name |
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constructorName x = fail $ "Unhandled constructor " ++ show x |
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|
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-- | Extract all constructor names from a given type. |
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reifyConsNames :: Name -> Q [String] |
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reifyConsNames name = do |
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reify_result <- reify name |
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case reify_result of |
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TyConI (DataD _ _ _ cons _) -> mapM (liftM nameBase . constructorName) cons |
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o -> fail $ "Unhandled name passed to reifyConsNames, expected\ |
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\ type constructor but got '" ++ show o ++ "'" |
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|
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-- | Builds the generic constructor-to-string function. |
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-- |
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-- This generates a simple function of the following form: |
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-- |
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-- @ |
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-- fname (ConStructorOne {}) = trans_fun("ConStructorOne") |
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-- fname (ConStructorTwo {}) = trans_fun("ConStructorTwo") |
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-- @ |
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-- |
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-- This builds a custom list of name\/string pairs and then uses |
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-- 'genToRaw' to actually generate the function. |
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genConstrToStr :: (String -> String) -> Name -> String -> Q [Dec] |
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genConstrToStr trans_fun name fname = do |
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cnames <- reifyConsNames name |
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let svalues = map (Left . trans_fun) cnames |
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genToRaw ''String (mkName fname) name $ zip cnames svalues |
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|
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-- | Constructor-to-string for OpCode. |
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genOpID :: Name -> String -> Q [Dec] |
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genOpID = genConstrToStr deCamelCase |
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|
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-- | Builds a list with all defined constructor names for a type. |
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-- |
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-- @ |
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-- vstr :: String |
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-- vstr = [...] |
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-- @ |
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-- |
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-- Where the actual values of the string are the constructor names |
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-- mapped via @trans_fun@. |
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genAllConstr :: (String -> String) -> Name -> String -> Q [Dec] |
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genAllConstr trans_fun name vstr = do |
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cnames <- reifyConsNames name |
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let svalues = sort $ map trans_fun cnames |
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vname = mkName vstr |
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sig = SigD vname (AppT ListT (ConT ''String)) |
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body = NormalB (ListE (map (LitE . StringL) svalues)) |
529 |
return $ [sig, ValD (VarP vname) body []] |
530 |
|
531 |
-- | Generates a list of all defined opcode IDs. |
532 |
genAllOpIDs :: Name -> String -> Q [Dec] |
533 |
genAllOpIDs = genAllConstr deCamelCase |
534 |
|
535 |
-- | OpCode parameter (field) type. |
536 |
type OpParam = (String, Q Type, Q Exp) |
537 |
|
538 |
-- * Python code generation |
539 |
|
540 |
-- | Converts Haskell values into Python values |
541 |
-- |
542 |
-- This is necessary for the default values of opcode parameters and |
543 |
-- return values. For example, if a default value or return type is a |
544 |
-- Data.Map, then it must be shown as a Python dictioanry. |
545 |
class Show a => PyValue a where |
546 |
showValue :: a -> String |
547 |
showValue = show |
548 |
|
549 |
-- | Encapsulates Python default values |
550 |
data PyValueEx = forall a. PyValue a => PyValueEx a |
551 |
|
552 |
-- | Transfers opcode data between the opcode description (through |
553 |
-- @genOpCode@) and the Python code generation functions. |
554 |
type OpCodeDescriptor = |
555 |
(String, String, String, [String], |
556 |
[String], [Maybe PyValueEx], [String], String) |
557 |
|
558 |
-- | Strips out the module name |
559 |
-- |
560 |
-- @ |
561 |
-- pyBaseName "Data.Map" = "Map" |
562 |
-- @ |
563 |
pyBaseName :: String -> String |
564 |
pyBaseName str = |
565 |
case span (/= '.') str of |
566 |
(x, []) -> x |
567 |
(_, _:x) -> pyBaseName x |
568 |
|
569 |
-- | Converts a Haskell type name into a Python type name. |
570 |
-- |
571 |
-- @ |
572 |
-- pyTypename "Bool" = "ht.TBool" |
573 |
-- @ |
574 |
pyTypeName :: Show a => a -> String |
575 |
pyTypeName name = |
576 |
"ht.T" ++ (case pyBaseName (show name) of |
577 |
"()" -> "None" |
578 |
"Map" -> "DictOf" |
579 |
"Set" -> "SetOf" |
580 |
"Either" -> "Or" |
581 |
"GenericContainer" -> "DictOf" |
582 |
"JSValue" -> "Any" |
583 |
"JSObject" -> "Object" |
584 |
str -> str) |
585 |
|
586 |
-- | Converts a Haskell type into a Python type. |
587 |
-- |
588 |
-- @ |
589 |
-- pyType [Int] = "ht.TListOf(ht.TInt)" |
590 |
-- @ |
591 |
pyType :: Type -> Q String |
592 |
pyType (AppT typ1 typ2) = |
593 |
do t <- pyCall typ1 typ2 |
594 |
return $ t ++ ")" |
595 |
|
596 |
pyType (ConT name) = return (pyTypeName name) |
597 |
pyType ListT = return "ht.TListOf" |
598 |
pyType (TupleT _) = return "ht.TTupleOf" |
599 |
pyType typ = error $ "unhandled case for type " ++ show typ |
600 |
|
601 |
-- | Converts a Haskell type application into a Python type. |
602 |
-- |
603 |
-- @ |
604 |
-- Maybe Int = "ht.TMaybe(ht.TInt)" |
605 |
-- @ |
606 |
pyCall :: Type -> Type -> Q String |
607 |
pyCall (AppT typ1 typ2) arg = |
608 |
do t <- pyCall typ1 typ2 |
609 |
targ <- pyType arg |
610 |
return $ t ++ ", " ++ targ |
611 |
|
612 |
pyCall typ1 typ2 = |
613 |
do t1 <- pyType typ1 |
614 |
t2 <- pyType typ2 |
615 |
return $ t1 ++ "(" ++ t2 |
616 |
|
617 |
-- | @pyType opt typ@ converts Haskell type @typ@ into a Python type, |
618 |
-- where @opt@ determines if the converted type is optional (i.e., |
619 |
-- Maybe). |
620 |
-- |
621 |
-- @ |
622 |
-- pyType False [Int] = "ht.TListOf(ht.TInt)" (mandatory) |
623 |
-- pyType True [Int] = "ht.TMaybe(ht.TListOf(ht.TInt))" (optional) |
624 |
-- @ |
625 |
pyOptionalType :: Bool -> Type -> Q String |
626 |
pyOptionalType opt typ |
627 |
| opt = do t <- pyType typ |
628 |
return $ "ht.TMaybe(" ++ t ++ ")" |
629 |
| otherwise = pyType typ |
630 |
|
631 |
-- | Optionally encapsulates default values in @PyValueEx@. |
632 |
-- |
633 |
-- @maybeApp exp typ@ returns a quoted expression that encapsulates |
634 |
-- the default value @exp@ of an opcode parameter cast to @typ@ in a |
635 |
-- @PyValueEx@, if @exp@ is @Just@. Otherwise, it returns a quoted |
636 |
-- expression with @Nothing@. |
637 |
maybeApp :: Maybe (Q Exp) -> Q Type -> Q Exp |
638 |
maybeApp Nothing _ = |
639 |
[| Nothing |] |
640 |
|
641 |
maybeApp (Just expr) typ = |
642 |
[| Just ($(conE (mkName "PyValueEx")) ($expr :: $typ)) |] |
643 |
|
644 |
|
645 |
-- | Generates a Python type according to whether the field is |
646 |
-- optional |
647 |
genPyType :: OptionalType -> Q Type -> Q ExpQ |
648 |
genPyType opt typ = |
649 |
do t <- typ |
650 |
stringE <$> pyOptionalType (opt /= NotOptional) t |
651 |
|
652 |
-- | Generates Python types from opcode parameters. |
653 |
genPyTypes :: [Field] -> Q ExpQ |
654 |
genPyTypes fs = |
655 |
listE <$> mapM (\f -> genPyType (fieldIsOptional f) (fieldType f)) fs |
656 |
|
657 |
-- | Generates Python default values from opcode parameters. |
658 |
genPyDefaults :: [Field] -> ExpQ |
659 |
genPyDefaults fs = |
660 |
listE $ map (\f -> maybeApp (fieldDefault f) (fieldType f)) fs |
661 |
|
662 |
-- | Generates a Haskell function call to "showPyClass" with the |
663 |
-- necessary information on how to build the Python class string. |
664 |
pyClass :: OpCodeConstructor -> ExpQ |
665 |
pyClass (consName, consType, consDoc, consFields, consDscField) = |
666 |
do let pyClassVar = varNameE "showPyClass" |
667 |
consName' = stringE consName |
668 |
consType' <- genPyType NotOptional consType |
669 |
let consDoc' = stringE consDoc |
670 |
consFieldNames = listE $ map (stringE . fieldName) consFields |
671 |
consFieldDocs = listE $ map (stringE . fieldDoc) consFields |
672 |
consFieldTypes <- genPyTypes consFields |
673 |
let consFieldDefaults = genPyDefaults consFields |
674 |
[| ($consName', |
675 |
$consType', |
676 |
$consDoc', |
677 |
$consFieldNames, |
678 |
$consFieldTypes, |
679 |
$consFieldDefaults, |
680 |
$consFieldDocs, |
681 |
consDscField) |] |
682 |
|
683 |
-- | Generates a function called "pyClasses" that holds the list of |
684 |
-- all the opcode descriptors necessary for generating the Python |
685 |
-- opcodes. |
686 |
pyClasses :: [OpCodeConstructor] -> Q [Dec] |
687 |
pyClasses cons = |
688 |
do let name = mkName "pyClasses" |
689 |
sig = SigD name (AppT ListT (ConT ''OpCodeDescriptor)) |
690 |
fn <- FunD name <$> (:[]) <$> declClause cons |
691 |
return [sig, fn] |
692 |
where declClause c = |
693 |
clause [] (normalB (ListE <$> mapM pyClass c)) [] |
694 |
|
695 |
-- | Converts from an opcode constructor to a Luxi constructor. |
696 |
opcodeConsToLuxiCons :: (a, b, c, d, e) -> (a, d) |
697 |
opcodeConsToLuxiCons (x, _, _, y, _) = (x, y) |
698 |
|
699 |
-- | Generates the OpCode data type. |
700 |
-- |
701 |
-- This takes an opcode logical definition, and builds both the |
702 |
-- datatype and the JSON serialisation out of it. We can't use a |
703 |
-- generic serialisation since we need to be compatible with Ganeti's |
704 |
-- own, so we have a few quirks to work around. |
705 |
genOpCode :: String -- ^ Type name to use |
706 |
-> [OpCodeConstructor] -- ^ Constructor name and parameters |
707 |
-> Q [Dec] |
708 |
genOpCode name cons = do |
709 |
let tname = mkName name |
710 |
decl_d <- mapM (\(cname, _, _, fields, _) -> do |
711 |
-- we only need the type of the field, without Q |
712 |
fields' <- mapM (fieldTypeInfo "op") fields |
713 |
return $ RecC (mkName cname) fields') |
714 |
cons |
715 |
let declD = DataD [] tname [] decl_d [''Show, ''Eq] |
716 |
let (allfsig, allffn) = genAllOpFields "allOpFields" cons |
717 |
save_decs <- genSaveOpCode tname "saveOpCode" "toDictOpCode" |
718 |
(map opcodeConsToLuxiCons cons) saveConstructor True |
719 |
(loadsig, loadfn) <- genLoadOpCode cons |
720 |
pyDecls <- pyClasses cons |
721 |
return $ [declD, allfsig, allffn, loadsig, loadfn] ++ save_decs ++ pyDecls |
722 |
|
723 |
-- | Generates the function pattern returning the list of fields for a |
724 |
-- given constructor. |
725 |
genOpConsFields :: OpCodeConstructor -> Clause |
726 |
genOpConsFields (cname, _, _, fields, _) = |
727 |
let op_id = deCamelCase cname |
728 |
fvals = map (LitE . StringL) . sort . nub $ |
729 |
concatMap (\f -> fieldName f:fieldExtraKeys f) fields |
730 |
in Clause [LitP (StringL op_id)] (NormalB $ ListE fvals) [] |
731 |
|
732 |
-- | Generates a list of all fields of an opcode constructor. |
733 |
genAllOpFields :: String -- ^ Function name |
734 |
-> [OpCodeConstructor] -- ^ Object definition |
735 |
-> (Dec, Dec) |
736 |
genAllOpFields sname opdefs = |
737 |
let cclauses = map genOpConsFields opdefs |
738 |
other = Clause [WildP] (NormalB (ListE [])) [] |
739 |
fname = mkName sname |
740 |
sigt = AppT (AppT ArrowT (ConT ''String)) (AppT ListT (ConT ''String)) |
741 |
in (SigD fname sigt, FunD fname (cclauses++[other])) |
742 |
|
743 |
-- | Generates the \"save\" clause for an entire opcode constructor. |
744 |
-- |
745 |
-- This matches the opcode with variables named the same as the |
746 |
-- constructor fields (just so that the spliced in code looks nicer), |
747 |
-- and passes those name plus the parameter definition to 'saveObjectField'. |
748 |
saveConstructor :: LuxiConstructor -- ^ The constructor |
749 |
-> Q Clause -- ^ Resulting clause |
750 |
saveConstructor (sname, fields) = do |
751 |
let cname = mkName sname |
752 |
fnames <- mapM (newName . fieldVariable) fields |
753 |
let pat = conP cname (map varP fnames) |
754 |
let felems = map (uncurry saveObjectField) (zip fnames fields) |
755 |
-- now build the OP_ID serialisation |
756 |
opid = [| [( $(stringE "OP_ID"), |
757 |
JSON.showJSON $(stringE . deCamelCase $ sname) )] |] |
758 |
flist = listE (opid:felems) |
759 |
-- and finally convert all this to a json object |
760 |
flist' = [| concat $flist |] |
761 |
clause [pat] (normalB flist') [] |
762 |
|
763 |
-- | Generates the main save opcode function. |
764 |
-- |
765 |
-- This builds a per-constructor match clause that contains the |
766 |
-- respective constructor-serialisation code. |
767 |
genSaveOpCode :: Name -- ^ Object ype |
768 |
-> String -- ^ To 'JSValue' function name |
769 |
-> String -- ^ To 'JSObject' function name |
770 |
-> [LuxiConstructor] -- ^ Object definition |
771 |
-> (LuxiConstructor -> Q Clause) -- ^ Constructor save fn |
772 |
-> Bool -- ^ Whether to generate |
773 |
-- obj or just a |
774 |
-- list\/tuple of values |
775 |
-> Q [Dec] |
776 |
genSaveOpCode tname jvalstr tdstr opdefs fn gen_object = do |
777 |
tdclauses <- mapM fn opdefs |
778 |
let typecon = ConT tname |
779 |
jvalname = mkName jvalstr |
780 |
jvalsig = AppT (AppT ArrowT typecon) (ConT ''JSON.JSValue) |
781 |
tdname = mkName tdstr |
782 |
tdsig <- [t| $(return typecon) -> [(String, JSON.JSValue)] |] |
783 |
jvalclause <- if gen_object |
784 |
then [| $makeObjE . $(varE tdname) |] |
785 |
else [| JSON.showJSON . map snd . $(varE tdname) |] |
786 |
return [ SigD tdname tdsig |
787 |
, FunD tdname tdclauses |
788 |
, SigD jvalname jvalsig |
789 |
, ValD (VarP jvalname) (NormalB jvalclause) []] |
790 |
|
791 |
-- | Generates load code for a single constructor of the opcode data type. |
792 |
loadConstructor :: OpCodeConstructor -> Q Exp |
793 |
loadConstructor (sname, _, _, fields, _) = do |
794 |
let name = mkName sname |
795 |
fbinds <- mapM loadObjectField fields |
796 |
let (fnames, fstmts) = unzip fbinds |
797 |
let cval = foldl (\accu fn -> AppE accu (VarE fn)) (ConE name) fnames |
798 |
fstmts' = fstmts ++ [NoBindS (AppE (VarE 'return) cval)] |
799 |
return $ DoE fstmts' |
800 |
|
801 |
-- | Generates the loadOpCode function. |
802 |
genLoadOpCode :: [OpCodeConstructor] -> Q (Dec, Dec) |
803 |
genLoadOpCode opdefs = do |
804 |
let fname = mkName "loadOpCode" |
805 |
arg1 = mkName "v" |
806 |
objname = mkName "o" |
807 |
opid = mkName "op_id" |
808 |
st1 <- bindS (varP objname) [| liftM JSON.fromJSObject |
809 |
(JSON.readJSON $(varE arg1)) |] |
810 |
st2 <- bindS (varP opid) [| $fromObjE $(varE objname) $(stringE "OP_ID") |] |
811 |
-- the match results (per-constructor blocks) |
812 |
mexps <- mapM loadConstructor opdefs |
813 |
fails <- [| fail $ "Unknown opcode " ++ $(varE opid) |] |
814 |
let mpats = map (\(me, (consName, _, _, _, _)) -> |
815 |
let mp = LitP . StringL . deCamelCase $ consName |
816 |
in Match mp (NormalB me) [] |
817 |
) $ zip mexps opdefs |
818 |
defmatch = Match WildP (NormalB fails) [] |
819 |
cst = NoBindS $ CaseE (VarE opid) $ mpats++[defmatch] |
820 |
body = DoE [st1, st2, cst] |
821 |
sigt <- [t| JSON.JSValue -> JSON.Result $(conT (mkName "OpCode")) |] |
822 |
return $ (SigD fname sigt, FunD fname [Clause [VarP arg1] (NormalB body) []]) |
823 |
|
824 |
-- * Template code for luxi |
825 |
|
826 |
-- | Constructor-to-string for LuxiOp. |
827 |
genStrOfOp :: Name -> String -> Q [Dec] |
828 |
genStrOfOp = genConstrToStr id |
829 |
|
830 |
-- | Constructor-to-string for MsgKeys. |
831 |
genStrOfKey :: Name -> String -> Q [Dec] |
832 |
genStrOfKey = genConstrToStr ensureLower |
833 |
|
834 |
-- | Generates the LuxiOp data type. |
835 |
-- |
836 |
-- This takes a Luxi operation definition and builds both the |
837 |
-- datatype and the function transforming the arguments to JSON. |
838 |
-- We can't use anything less generic, because the way different |
839 |
-- operations are serialized differs on both parameter- and top-level. |
840 |
-- |
841 |
-- There are two things to be defined for each parameter: |
842 |
-- |
843 |
-- * name |
844 |
-- |
845 |
-- * type |
846 |
-- |
847 |
genLuxiOp :: String -> [LuxiConstructor] -> Q [Dec] |
848 |
genLuxiOp name cons = do |
849 |
let tname = mkName name |
850 |
decl_d <- mapM (\(cname, fields) -> do |
851 |
-- we only need the type of the field, without Q |
852 |
fields' <- mapM actualFieldType fields |
853 |
let fields'' = zip (repeat NotStrict) fields' |
854 |
return $ NormalC (mkName cname) fields'') |
855 |
cons |
856 |
let declD = DataD [] (mkName name) [] decl_d [''Show, ''Eq] |
857 |
save_decs <- genSaveOpCode tname "opToArgs" "opToDict" |
858 |
cons saveLuxiConstructor False |
859 |
req_defs <- declareSADT "LuxiReq" . |
860 |
map (\(str, _) -> ("Req" ++ str, mkName ("luxiReq" ++ str))) $ |
861 |
cons |
862 |
return $ declD:save_decs ++ req_defs |
863 |
|
864 |
-- | Generates the \"save\" clause for entire LuxiOp constructor. |
865 |
saveLuxiConstructor :: LuxiConstructor -> Q Clause |
866 |
saveLuxiConstructor (sname, fields) = do |
867 |
let cname = mkName sname |
868 |
fnames <- mapM (newName . fieldVariable) fields |
869 |
let pat = conP cname (map varP fnames) |
870 |
let felems = map (uncurry saveObjectField) (zip fnames fields) |
871 |
flist = [| concat $(listE felems) |] |
872 |
clause [pat] (normalB flist) [] |
873 |
|
874 |
-- * "Objects" functionality |
875 |
|
876 |
-- | Extract the field's declaration from a Field structure. |
877 |
fieldTypeInfo :: String -> Field -> Q (Name, Strict, Type) |
878 |
fieldTypeInfo field_pfx fd = do |
879 |
t <- actualFieldType fd |
880 |
let n = mkName . (field_pfx ++) . fieldRecordName $ fd |
881 |
return (n, NotStrict, t) |
882 |
|
883 |
-- | Build an object declaration. |
884 |
buildObject :: String -> String -> [Field] -> Q [Dec] |
885 |
buildObject sname field_pfx fields = do |
886 |
let name = mkName sname |
887 |
fields_d <- mapM (fieldTypeInfo field_pfx) fields |
888 |
let decl_d = RecC name fields_d |
889 |
let declD = DataD [] name [] [decl_d] [''Show, ''Eq] |
890 |
ser_decls <- buildObjectSerialisation sname fields |
891 |
return $ declD:ser_decls |
892 |
|
893 |
-- | Generates an object definition: data type and its JSON instance. |
894 |
buildObjectSerialisation :: String -> [Field] -> Q [Dec] |
895 |
buildObjectSerialisation sname fields = do |
896 |
let name = mkName sname |
897 |
savedecls <- genSaveObject saveObjectField sname fields |
898 |
(loadsig, loadfn) <- genLoadObject loadObjectField sname fields |
899 |
shjson <- objectShowJSON sname |
900 |
rdjson <- objectReadJSON sname |
901 |
let instdecl = InstanceD [] (AppT (ConT ''JSON.JSON) (ConT name)) |
902 |
[rdjson, shjson] |
903 |
return $ savedecls ++ [loadsig, loadfn, instdecl] |
904 |
|
905 |
-- | The toDict function name for a given type. |
906 |
toDictName :: String -> Name |
907 |
toDictName sname = mkName ("toDict" ++ sname) |
908 |
|
909 |
-- | Generates the save object functionality. |
910 |
genSaveObject :: (Name -> Field -> Q Exp) |
911 |
-> String -> [Field] -> Q [Dec] |
912 |
genSaveObject save_fn sname fields = do |
913 |
let name = mkName sname |
914 |
fnames <- mapM (newName . fieldVariable) fields |
915 |
let pat = conP name (map varP fnames) |
916 |
let tdname = toDictName sname |
917 |
tdsigt <- [t| $(conT name) -> [(String, JSON.JSValue)] |] |
918 |
|
919 |
let felems = map (uncurry save_fn) (zip fnames fields) |
920 |
flist = listE felems |
921 |
-- and finally convert all this to a json object |
922 |
tdlist = [| concat $flist |] |
923 |
iname = mkName "i" |
924 |
tclause <- clause [pat] (normalB tdlist) [] |
925 |
cclause <- [| $makeObjE . $(varE tdname) |] |
926 |
let fname = mkName ("save" ++ sname) |
927 |
sigt <- [t| $(conT name) -> JSON.JSValue |] |
928 |
return [SigD tdname tdsigt, FunD tdname [tclause], |
929 |
SigD fname sigt, ValD (VarP fname) (NormalB cclause) []] |
930 |
|
931 |
-- | Generates the code for saving an object's field, handling the |
932 |
-- various types of fields that we have. |
933 |
saveObjectField :: Name -> Field -> Q Exp |
934 |
saveObjectField fvar field = |
935 |
case fieldIsOptional field of |
936 |
OptionalOmitNull -> [| case $(varE fvar) of |
937 |
Nothing -> [] |
938 |
Just v -> [( $nameE, JSON.showJSON v )] |
939 |
|] |
940 |
OptionalSerializeNull -> [| case $(varE fvar) of |
941 |
Nothing -> [( $nameE, JSON.JSNull )] |
942 |
Just v -> [( $nameE, JSON.showJSON v )] |
943 |
|] |
944 |
NotOptional -> |
945 |
case fieldShow field of |
946 |
-- Note: the order of actual:extra is important, since for |
947 |
-- some serialisation types (e.g. Luxi), we use tuples |
948 |
-- (positional info) rather than object (name info) |
949 |
Nothing -> [| [( $nameE, JSON.showJSON $fvarE)] |] |
950 |
Just fn -> [| let (actual, extra) = $fn $fvarE |
951 |
in ($nameE, JSON.showJSON actual):extra |
952 |
|] |
953 |
where nameE = stringE (fieldName field) |
954 |
fvarE = varE fvar |
955 |
|
956 |
-- | Generates the showJSON clause for a given object name. |
957 |
objectShowJSON :: String -> Q Dec |
958 |
objectShowJSON name = do |
959 |
body <- [| JSON.showJSON . $(varE . mkName $ "save" ++ name) |] |
960 |
return $ FunD 'JSON.showJSON [Clause [] (NormalB body) []] |
961 |
|
962 |
-- | Generates the load object functionality. |
963 |
genLoadObject :: (Field -> Q (Name, Stmt)) |
964 |
-> String -> [Field] -> Q (Dec, Dec) |
965 |
genLoadObject load_fn sname fields = do |
966 |
let name = mkName sname |
967 |
funname = mkName $ "load" ++ sname |
968 |
arg1 = mkName $ if null fields then "_" else "v" |
969 |
objname = mkName "o" |
970 |
opid = mkName "op_id" |
971 |
st1 <- bindS (varP objname) [| liftM JSON.fromJSObject |
972 |
(JSON.readJSON $(varE arg1)) |] |
973 |
fbinds <- mapM load_fn fields |
974 |
let (fnames, fstmts) = unzip fbinds |
975 |
let cval = foldl (\accu fn -> AppE accu (VarE fn)) (ConE name) fnames |
976 |
retstmt = [NoBindS (AppE (VarE 'return) cval)] |
977 |
-- FIXME: should we require an empty dict for an empty type? |
978 |
-- this allows any JSValue right now |
979 |
fstmts' = if null fields |
980 |
then retstmt |
981 |
else st1:fstmts ++ retstmt |
982 |
sigt <- [t| JSON.JSValue -> JSON.Result $(conT name) |] |
983 |
return $ (SigD funname sigt, |
984 |
FunD funname [Clause [VarP arg1] (NormalB (DoE fstmts')) []]) |
985 |
|
986 |
-- | Generates code for loading an object's field. |
987 |
loadObjectField :: Field -> Q (Name, Stmt) |
988 |
loadObjectField field = do |
989 |
let name = fieldVariable field |
990 |
fvar <- newName name |
991 |
-- these are used in all patterns below |
992 |
let objvar = varNameE "o" |
993 |
objfield = stringE (fieldName field) |
994 |
loadexp = |
995 |
if fieldIsOptional field /= NotOptional |
996 |
-- we treat both optional types the same, since |
997 |
-- 'maybeFromObj' can deal with both missing and null values |
998 |
-- appropriately (the same) |
999 |
then [| $(varE 'maybeFromObj) $objvar $objfield |] |
1000 |
else case fieldDefault field of |
1001 |
Just defv -> |
1002 |
[| $(varE 'fromObjWithDefault) $objvar |
1003 |
$objfield $defv |] |
1004 |
Nothing -> [| $fromObjE $objvar $objfield |] |
1005 |
bexp <- loadFn field loadexp objvar |
1006 |
|
1007 |
return (fvar, BindS (VarP fvar) bexp) |
1008 |
|
1009 |
-- | Builds the readJSON instance for a given object name. |
1010 |
objectReadJSON :: String -> Q Dec |
1011 |
objectReadJSON name = do |
1012 |
let s = mkName "s" |
1013 |
body <- [| case JSON.readJSON $(varE s) of |
1014 |
JSON.Ok s' -> $(varE .mkName $ "load" ++ name) s' |
1015 |
JSON.Error e -> |
1016 |
JSON.Error $ "Can't parse value for type " ++ |
1017 |
$(stringE name) ++ ": " ++ e |
1018 |
|] |
1019 |
return $ FunD 'JSON.readJSON [Clause [VarP s] (NormalB body) []] |
1020 |
|
1021 |
-- * Inheritable parameter tables implementation |
1022 |
|
1023 |
-- | Compute parameter type names. |
1024 |
paramTypeNames :: String -> (String, String) |
1025 |
paramTypeNames root = ("Filled" ++ root ++ "Params", |
1026 |
"Partial" ++ root ++ "Params") |
1027 |
|
1028 |
-- | Compute information about the type of a parameter field. |
1029 |
paramFieldTypeInfo :: String -> Field -> Q (Name, Strict, Type) |
1030 |
paramFieldTypeInfo field_pfx fd = do |
1031 |
t <- actualFieldType fd |
1032 |
let n = mkName . (++ "P") . (field_pfx ++) . |
1033 |
fieldRecordName $ fd |
1034 |
return (n, NotStrict, AppT (ConT ''Maybe) t) |
1035 |
|
1036 |
-- | Build a parameter declaration. |
1037 |
-- |
1038 |
-- This function builds two different data structures: a /filled/ one, |
1039 |
-- in which all fields are required, and a /partial/ one, in which all |
1040 |
-- fields are optional. Due to the current record syntax issues, the |
1041 |
-- fields need to be named differrently for the two structures, so the |
1042 |
-- partial ones get a /P/ suffix. |
1043 |
buildParam :: String -> String -> [Field] -> Q [Dec] |
1044 |
buildParam sname field_pfx fields = do |
1045 |
let (sname_f, sname_p) = paramTypeNames sname |
1046 |
name_f = mkName sname_f |
1047 |
name_p = mkName sname_p |
1048 |
fields_f <- mapM (fieldTypeInfo field_pfx) fields |
1049 |
fields_p <- mapM (paramFieldTypeInfo field_pfx) fields |
1050 |
let decl_f = RecC name_f fields_f |
1051 |
decl_p = RecC name_p fields_p |
1052 |
let declF = DataD [] name_f [] [decl_f] [''Show, ''Eq] |
1053 |
declP = DataD [] name_p [] [decl_p] [''Show, ''Eq] |
1054 |
ser_decls_f <- buildObjectSerialisation sname_f fields |
1055 |
ser_decls_p <- buildPParamSerialisation sname_p fields |
1056 |
fill_decls <- fillParam sname field_pfx fields |
1057 |
return $ [declF, declP] ++ ser_decls_f ++ ser_decls_p ++ fill_decls ++ |
1058 |
buildParamAllFields sname fields ++ |
1059 |
buildDictObjectInst name_f sname_f |
1060 |
|
1061 |
-- | Builds a list of all fields of a parameter. |
1062 |
buildParamAllFields :: String -> [Field] -> [Dec] |
1063 |
buildParamAllFields sname fields = |
1064 |
let vname = mkName ("all" ++ sname ++ "ParamFields") |
1065 |
sig = SigD vname (AppT ListT (ConT ''String)) |
1066 |
val = ListE $ map (LitE . StringL . fieldName) fields |
1067 |
in [sig, ValD (VarP vname) (NormalB val) []] |
1068 |
|
1069 |
-- | Builds the 'DictObject' instance for a filled parameter. |
1070 |
buildDictObjectInst :: Name -> String -> [Dec] |
1071 |
buildDictObjectInst name sname = |
1072 |
[InstanceD [] (AppT (ConT ''DictObject) (ConT name)) |
1073 |
[ValD (VarP 'toDict) (NormalB (VarE (toDictName sname))) []]] |
1074 |
|
1075 |
-- | Generates the serialisation for a partial parameter. |
1076 |
buildPParamSerialisation :: String -> [Field] -> Q [Dec] |
1077 |
buildPParamSerialisation sname fields = do |
1078 |
let name = mkName sname |
1079 |
savedecls <- genSaveObject savePParamField sname fields |
1080 |
(loadsig, loadfn) <- genLoadObject loadPParamField sname fields |
1081 |
shjson <- objectShowJSON sname |
1082 |
rdjson <- objectReadJSON sname |
1083 |
let instdecl = InstanceD [] (AppT (ConT ''JSON.JSON) (ConT name)) |
1084 |
[rdjson, shjson] |
1085 |
return $ savedecls ++ [loadsig, loadfn, instdecl] |
1086 |
|
1087 |
-- | Generates code to save an optional parameter field. |
1088 |
savePParamField :: Name -> Field -> Q Exp |
1089 |
savePParamField fvar field = do |
1090 |
checkNonOptDef field |
1091 |
let actualVal = mkName "v" |
1092 |
normalexpr <- saveObjectField actualVal field |
1093 |
-- we have to construct the block here manually, because we can't |
1094 |
-- splice-in-splice |
1095 |
return $ CaseE (VarE fvar) [ Match (ConP 'Nothing []) |
1096 |
(NormalB (ConE '[])) [] |
1097 |
, Match (ConP 'Just [VarP actualVal]) |
1098 |
(NormalB normalexpr) [] |
1099 |
] |
1100 |
|
1101 |
-- | Generates code to load an optional parameter field. |
1102 |
loadPParamField :: Field -> Q (Name, Stmt) |
1103 |
loadPParamField field = do |
1104 |
checkNonOptDef field |
1105 |
let name = fieldName field |
1106 |
fvar <- newName name |
1107 |
-- these are used in all patterns below |
1108 |
let objvar = varNameE "o" |
1109 |
objfield = stringE name |
1110 |
loadexp = [| $(varE 'maybeFromObj) $objvar $objfield |] |
1111 |
bexp <- loadFn field loadexp objvar |
1112 |
return (fvar, BindS (VarP fvar) bexp) |
1113 |
|
1114 |
-- | Builds a simple declaration of type @n_x = fromMaybe f_x p_x@. |
1115 |
buildFromMaybe :: String -> Q Dec |
1116 |
buildFromMaybe fname = |
1117 |
valD (varP (mkName $ "n_" ++ fname)) |
1118 |
(normalB [| $(varE 'fromMaybe) |
1119 |
$(varNameE $ "f_" ++ fname) |
1120 |
$(varNameE $ "p_" ++ fname) |]) [] |
1121 |
|
1122 |
-- | Builds a function that executes the filling of partial parameter |
1123 |
-- from a full copy (similar to Python's fillDict). |
1124 |
fillParam :: String -> String -> [Field] -> Q [Dec] |
1125 |
fillParam sname field_pfx fields = do |
1126 |
let fnames = map (\fd -> field_pfx ++ fieldRecordName fd) fields |
1127 |
(sname_f, sname_p) = paramTypeNames sname |
1128 |
oname_f = "fobj" |
1129 |
oname_p = "pobj" |
1130 |
name_f = mkName sname_f |
1131 |
name_p = mkName sname_p |
1132 |
fun_name = mkName $ "fill" ++ sname ++ "Params" |
1133 |
le_full = ValD (ConP name_f (map (VarP . mkName . ("f_" ++)) fnames)) |
1134 |
(NormalB . VarE . mkName $ oname_f) [] |
1135 |
le_part = ValD (ConP name_p (map (VarP . mkName . ("p_" ++)) fnames)) |
1136 |
(NormalB . VarE . mkName $ oname_p) [] |
1137 |
obj_new = foldl (\accu vname -> AppE accu (VarE vname)) (ConE name_f) |
1138 |
$ map (mkName . ("n_" ++)) fnames |
1139 |
le_new <- mapM buildFromMaybe fnames |
1140 |
funt <- [t| $(conT name_f) -> $(conT name_p) -> $(conT name_f) |] |
1141 |
let sig = SigD fun_name funt |
1142 |
fclause = Clause [VarP (mkName oname_f), VarP (mkName oname_p)] |
1143 |
(NormalB $ LetE (le_full:le_part:le_new) obj_new) [] |
1144 |
fun = FunD fun_name [fclause] |
1145 |
return [sig, fun] |
1146 |
|
1147 |
-- * Template code for exceptions |
1148 |
|
1149 |
-- | Exception simple error message field. |
1150 |
excErrMsg :: (String, Q Type) |
1151 |
excErrMsg = ("errMsg", [t| String |]) |
1152 |
|
1153 |
-- | Builds an exception type definition. |
1154 |
genException :: String -- ^ Name of new type |
1155 |
-> SimpleObject -- ^ Constructor name and parameters |
1156 |
-> Q [Dec] |
1157 |
genException name cons = do |
1158 |
let tname = mkName name |
1159 |
declD <- buildSimpleCons tname cons |
1160 |
(savesig, savefn) <- genSaveSimpleObj tname ("save" ++ name) cons $ |
1161 |
uncurry saveExcCons |
1162 |
(loadsig, loadfn) <- genLoadExc tname ("load" ++ name) cons |
1163 |
return [declD, loadsig, loadfn, savesig, savefn] |
1164 |
|
1165 |
-- | Generates the \"save\" clause for an entire exception constructor. |
1166 |
-- |
1167 |
-- This matches the exception with variables named the same as the |
1168 |
-- constructor fields (just so that the spliced in code looks nicer), |
1169 |
-- and calls showJSON on it. |
1170 |
saveExcCons :: String -- ^ The constructor name |
1171 |
-> [SimpleField] -- ^ The parameter definitions for this |
1172 |
-- constructor |
1173 |
-> Q Clause -- ^ Resulting clause |
1174 |
saveExcCons sname fields = do |
1175 |
let cname = mkName sname |
1176 |
fnames <- mapM (newName . fst) fields |
1177 |
let pat = conP cname (map varP fnames) |
1178 |
felems = if null fnames |
1179 |
then conE '() -- otherwise, empty list has no type |
1180 |
else listE $ map (\f -> [| JSON.showJSON $(varE f) |]) fnames |
1181 |
let tup = tupE [ litE (stringL sname), felems ] |
1182 |
clause [pat] (normalB [| JSON.showJSON $tup |]) [] |
1183 |
|
1184 |
-- | Generates load code for a single constructor of an exception. |
1185 |
-- |
1186 |
-- Generates the code (if there's only one argument, we will use a |
1187 |
-- list, not a tuple: |
1188 |
-- |
1189 |
-- @ |
1190 |
-- do |
1191 |
-- (x1, x2, ...) <- readJSON args |
1192 |
-- return $ Cons x1 x2 ... |
1193 |
-- @ |
1194 |
loadExcConstructor :: Name -> String -> [SimpleField] -> Q Exp |
1195 |
loadExcConstructor inname sname fields = do |
1196 |
let name = mkName sname |
1197 |
f_names <- mapM (newName . fst) fields |
1198 |
let read_args = AppE (VarE 'JSON.readJSON) (VarE inname) |
1199 |
let binds = case f_names of |
1200 |
[x] -> BindS (ListP [VarP x]) |
1201 |
_ -> BindS (TupP (map VarP f_names)) |
1202 |
cval = foldl (\accu fn -> AppE accu (VarE fn)) (ConE name) f_names |
1203 |
return $ DoE [binds read_args, NoBindS (AppE (VarE 'return) cval)] |
1204 |
|
1205 |
{-| Generates the loadException function. |
1206 |
|
1207 |
This generates a quite complicated function, along the lines of: |
1208 |
|
1209 |
@ |
1210 |
loadFn (JSArray [JSString name, args]) = case name of |
1211 |
"A1" -> do |
1212 |
(x1, x2, ...) <- readJSON args |
1213 |
return $ A1 x1 x2 ... |
1214 |
"a2" -> ... |
1215 |
s -> fail $ "Unknown exception" ++ s |
1216 |
loadFn v = fail $ "Expected array but got " ++ show v |
1217 |
@ |
1218 |
-} |
1219 |
genLoadExc :: Name -> String -> SimpleObject -> Q (Dec, Dec) |
1220 |
genLoadExc tname sname opdefs = do |
1221 |
let fname = mkName sname |
1222 |
exc_name <- newName "name" |
1223 |
exc_args <- newName "args" |
1224 |
exc_else <- newName "s" |
1225 |
arg_else <- newName "v" |
1226 |
fails <- [| fail $ "Unknown exception '" ++ $(varE exc_else) ++ "'" |] |
1227 |
-- default match for unknown exception name |
1228 |
let defmatch = Match (VarP exc_else) (NormalB fails) [] |
1229 |
-- the match results (per-constructor blocks) |
1230 |
str_matches <- |
1231 |
mapM (\(s, params) -> do |
1232 |
body_exp <- loadExcConstructor exc_args s params |
1233 |
return $ Match (LitP (StringL s)) (NormalB body_exp) []) |
1234 |
opdefs |
1235 |
-- the first function clause; we can't use [| |] due to TH |
1236 |
-- limitations, so we have to build the AST by hand |
1237 |
let clause1 = Clause [ConP 'JSON.JSArray |
1238 |
[ListP [ConP 'JSON.JSString [VarP exc_name], |
1239 |
VarP exc_args]]] |
1240 |
(NormalB (CaseE (AppE (VarE 'JSON.fromJSString) |
1241 |
(VarE exc_name)) |
1242 |
(str_matches ++ [defmatch]))) [] |
1243 |
-- the fail expression for the second function clause |
1244 |
fail_type <- [| fail $ "Invalid exception: expected '(string, [args])' " ++ |
1245 |
" but got " ++ show (pp_value $(varE arg_else)) ++ "'" |
1246 |
|] |
1247 |
-- the second function clause |
1248 |
let clause2 = Clause [VarP arg_else] (NormalB fail_type) [] |
1249 |
sigt <- [t| JSON.JSValue -> JSON.Result $(conT tname) |] |
1250 |
return $ (SigD fname sigt, FunD fname [clause1, clause2]) |