Safe Haskell	None
Language	Haskell2010

Lorentz.UStore.Migration.Diff

Synopsis

type FieldInfo = (Symbol, Type)
data DiffKind
- = ToAdd
- | ToDel
type DiffItem = (DiffKind, FieldInfo)
type BuildDiff oldTemplate newTemplate = LiftToDiff 'ToAdd (LinearizeUStore newTemplate // LinearizeUStore oldTemplate) ++ LiftToDiff 'ToDel (LinearizeUStore oldTemplate // LinearizeUStore newTemplate)
type ShowDiff diff = 'Text "Migration is incomplete, remaining diff:" :$$: ShowDiffItems diff
type family RequireEmptyDiff (diff :: [DiffItem]) :: Constraint where ...
type LinearizeUStore a = GLinearizeUStore (Rep a)
data LinearizeUStoreF (template :: Type) :: Exp [FieldInfo]
type family AllUStoreFieldsF (template :: Type) :: Exp [Symbol] where ...
data DiffCoverage
- = DcAdd
- | DcRemove
type family CoverDiff (cover :: DiffCoverage) (field :: Symbol) (diff :: [DiffItem]) :: (Type, [DiffItem]) where ...
type family CoverDiffMany (diff :: [DiffItem]) (covers :: [DiffCoverageItem]) :: [DiffItem] where ...

Documentation

type FieldInfo = (Symbol, Type) Source #

Information about single field of UStore.

data DiffKind Source #

What should happen with a particular UStoreItem.

Constructors

ToAdd
ToDel

Instances

Instances details

(RequireEmptyDiff d1, t1 ~ t2) => MigrationFinishCheckPosition (MigrationBlocks o n d1 t1 ('[] :: [DiffItem]) t2) Source #	This version can be used in `mkUStoreMultiMigration` as the last migration block.
Instance details Defined in Lorentz.UStore.Migration.Blocks Methods migrationFinish :: MigrationBlocks o n d1 t1 '[] t2 Source #

type DiffItem = (DiffKind, FieldInfo) Source #

Single piece of a diff.

type BuildDiff oldTemplate newTemplate = LiftToDiff 'ToAdd (LinearizeUStore newTemplate // LinearizeUStore oldTemplate) ++ LiftToDiff 'ToDel (LinearizeUStore oldTemplate // LinearizeUStore newTemplate) Source #

Make up a migration diff between given old and new UStore templates.

type ShowDiff diff = 'Text "Migration is incomplete, remaining diff:" :$$: ShowDiffItems diff Source #

Renders human-readable message describing given diff.

type family RequireEmptyDiff (diff :: [DiffItem]) :: Constraint where ... Source #

Helper type family which dumps error message about remaining diff if such is present.

Equations

RequireEmptyDiff '[] = ()
RequireEmptyDiff diff = TypeError (ShowDiff diff)

type LinearizeUStore a = GLinearizeUStore (Rep a) Source #

Get information about all fields of UStore template in a list.

In particular, this recursivelly traverses template and retrives names and types of fields. Semantic wrappers like UStoreField and |~> in field types are returned as-is.

data LinearizeUStoreF (template :: Type) :: Exp [FieldInfo] Source #

Instances

Instances details

type Eval (LinearizeUStoreF template :: [FieldInfo] -> Type) Source #
Instance details Defined in Lorentz.UStore.Migration.Diff type Eval (LinearizeUStoreF template :: [FieldInfo] -> Type) = LinearizeUStore template

type family AllUStoreFieldsF (template :: Type) :: Exp [Symbol] where ... Source #

Get only field names of UStore template.

Equations

AllUStoreFieldsF template = Map Fst =<< LinearizeUStoreF template

data DiffCoverage Source #

Cover the respective part of diff. Maybe fail if such action is not required.

This type is very similar to DiffKind, but we still use another type as 1. Their kinds will differ - no chance to mix up anything. 2. One day there might appear more complex actions.

Constructors

DcAdd
DcRemove

type family CoverDiff (cover :: DiffCoverage) (field :: Symbol) (diff :: [DiffItem]) :: (Type, [DiffItem]) where ... Source #

Apply given diff coverage, returning type of affected field and modified diff.

Equations

CoverDiff cover field diff = Eval (CoverDiffF '(cover, field) diff)

type family CoverDiffMany (diff :: [DiffItem]) (covers :: [DiffCoverageItem]) :: [DiffItem] where ... Source #

Apply multiple coverage steps.

Equations

CoverDiffMany diff '[] = diff
CoverDiffMany diff ('(dc, '(field, ty)) ': cs) = CoverDiffMany (HandleCoverRes field ty (CoverDiff dc field diff)) cs