SybWidget-0.4.0: Library which aids constructing generic (SYB3-based) widgetsSource codeContentsIndex
Graphics.UI.SybWidget.InstanceCreator
Description
Contains functions to automatically create instances from data type definitions.
Synopsis
gGenUpTo :: forall a ctx. Data ctx a => Proxy ctx -> Int -> [a]
createInstance :: forall a ctx. Data ctx a => Proxy ctx -> Maybe a
createInstance' :: forall a ctx. Data ctx a => Proxy ctx -> a -> Maybe a
instanceFromConstr :: forall a ctx. Data ctx a => Proxy ctx -> Constr -> Maybe a
Documentation
gGenUpToSource
:: forall a ctx . Data ctx a
=> Proxy ctx
-> IntMax number of recursions
-> [a]

Generates all possible instances of a, while using no more than n levels of recursion. Each subtype requires another level of recursion. For example:

Branch (Branch Leaf 17) (Leaf 3)

would require 4 levels of recursion. One for the first branch, one for second branch, one for the left Leaf, and one for the Int (the seventeen). The right part of the first branch (Left 3) would be done in two recursions.

createInstance :: forall a ctx. Data ctx a => Proxy ctx -> Maybe aSource
Creates an instance of a Haskell type. For this to work the compiler must be able to deduce the type from the callee's context.
createInstance' :: forall a ctx. Data ctx a => Proxy ctx -> a -> Maybe aSource
Like createInstance excepts it uses a phantom type to elicit the correct type to return.
instanceFromConstrSource
:: forall a ctx . Data ctx a
=> Proxy ctx
-> Constr
-> Maybe aReturns Nothing if it was not possible to create the value.
Creates an instance with a specific constructor.
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