graphql-engine/server/src-lib/Hasura/Backends/DataConnector/IR/Name.hs

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{-# LANGUAGE StandaloneKindSignatures #-}
module Hasura.Backends.DataConnector.IR.Name
( Name (..),
NameType (..),
)
where
--------------------------------------------------------------------------------
import Data.Aeson (FromJSON, FromJSONKey, ToJSON, ToJSONKey)
import Data.Kind (Type)
import Data.Text.Extended (ToTxt)
import Hasura.Backends.DataConnector.API qualified as API
An `ErrorMessage` type, to encapsulate. This introduces an `ErrorMessage` newtype which wraps `Text` in a manner which is designed to be easy to construct, and difficult to deconstruct. It provides functionality similar to `Data.Text.Extended`, but designed _only_ for error messages. Error messages are constructed through `fromString`, concatenation, or the `toErrorValue` function, which is designed to be overridden for all meaningful domain types that might show up in an error message. Notably, there are not and should never be instances of `ToErrorValue` for `String`, `Text`, `Int`, etc. This is so that we correctly represent the value in a way that is specific to its type. For example, all `Name` values (from the _graphql-parser-hs_ library) are single-quoted now; no exceptions. I have mostly had to add `instance ToErrorValue` for various backend types (and also add newtypes where necessary). Some of these are not strictly necessary for this changeset, as I had bigger aspirations when I started. These aspirations have been tempered by trying and failing twice. As such, in this changeset, I have started by introducing this type to the `parseError` and `parseErrorWith` functions. In the future, I would like to extend this to the `QErr` record and the various `throwError` functions, but this is a much larger task and should probably be done in stages. For now, `toErrorMessage` and `fromErrorMessage` are provided for conversion to and from `Text`, but the intent is to stop exporting these once all error messages are converted to the new type. PR-URL: https://github.com/hasura/graphql-engine-mono/pull/5018 GitOrigin-RevId: 84b37e238992e4312255a87ca44f41af65e2d89a
2022-07-18 23:26:01 +03:00
import Hasura.Base.ErrorValue qualified as ErrorValue
import Hasura.Base.ToErrorValue
import Hasura.Incremental (Cacheable)
import Hasura.Prelude
import Witch qualified
--------------------------------------------------------------------------------
-- | A tagged, opaque wrapper around 'Text' that provides a number of derived
-- derived instances (primarily as required by the @Backend@ typeclass).
--
-- This wrapper is indexed by 'NameType' so that different "names" can be
-- represented as semantically distinct types without the boilerplate of
-- actually defining these wrappers separately.
type Name :: NameType -> Type
newtype Name ty = Name {unName :: Text}
deriving stock (Data, Eq, Generic, Ord, Show)
deriving newtype
( Cacheable,
FromJSON,
FromJSONKey,
Hashable,
NFData,
ToJSON,
ToJSONKey,
ToTxt
)
An `ErrorMessage` type, to encapsulate. This introduces an `ErrorMessage` newtype which wraps `Text` in a manner which is designed to be easy to construct, and difficult to deconstruct. It provides functionality similar to `Data.Text.Extended`, but designed _only_ for error messages. Error messages are constructed through `fromString`, concatenation, or the `toErrorValue` function, which is designed to be overridden for all meaningful domain types that might show up in an error message. Notably, there are not and should never be instances of `ToErrorValue` for `String`, `Text`, `Int`, etc. This is so that we correctly represent the value in a way that is specific to its type. For example, all `Name` values (from the _graphql-parser-hs_ library) are single-quoted now; no exceptions. I have mostly had to add `instance ToErrorValue` for various backend types (and also add newtypes where necessary). Some of these are not strictly necessary for this changeset, as I had bigger aspirations when I started. These aspirations have been tempered by trying and failing twice. As such, in this changeset, I have started by introducing this type to the `parseError` and `parseErrorWith` functions. In the future, I would like to extend this to the `QErr` record and the various `throwError` functions, but this is a much larger task and should probably be done in stages. For now, `toErrorMessage` and `fromErrorMessage` are provided for conversion to and from `Text`, but the intent is to stop exporting these once all error messages are converted to the new type. PR-URL: https://github.com/hasura/graphql-engine-mono/pull/5018 GitOrigin-RevId: 84b37e238992e4312255a87ca44f41af65e2d89a
2022-07-18 23:26:01 +03:00
instance ToErrorValue (Name ty) where
toErrorValue = ErrorValue.squote . unName
instance Witch.From API.ColumnName (Name 'Column) where
from (API.ColumnName n) = Name n
instance Witch.From (Name 'Column) API.ColumnName where
from (Name n) = API.ColumnName n
instance Witch.From API.RelationshipName (Name 'Relationship) where
from (API.RelationshipName n) = Name n
instance Witch.From (Name 'Relationship) API.RelationshipName where
from (Name n) = API.RelationshipName n
instance Witch.From Text (Name 'Column) where
from = coerce
instance Witch.From Text (Name 'Relationship) where
from = coerce
-- | The "type" of "name" that the 'Name' type is meant to provide a textual
-- representation for.
--
-- In other words: an enumeration of all the types for which 'Name' acts as a
-- shared abstraction.
data NameType
= Column
| Relationship