Development.Shake.Rule

This module is used for defining new types of rules for Shake build systems. Most users will find the built-in set of rules sufficient.

Documentation

type ShakeValue a = (Show a, Typeable a, Eq a, Hashable a, Binary a, NFData a)

Define an alias for the six type classes required for things involved in Shake Rules. This alias is only available in GHC 7.4 and above, and requires the ConstraintKinds extension.

To define your own values meeting the necessary constraints it is convenient to use the extensions GeneralizedNewtypeDeriving and DeriveDataTypeable to write:

 newtype MyType = MyType (String, Bool) deriving (Show,Typeable,Eq,Hashable,Binary,NFData)

class (ShakeValue key, ShakeValue value) => Rule key value where

Define a pair of types that can be used by Shake rules. To import all the type classes required see Development.Shake.Classes.

Methods

storedValue :: ShakeOptions -> key -> IO (Maybe value)

Retrieve the value associated with a key, if available.

As an example for filenames/timestamps, if the file exists you should return Just the timestamp, but otherwise return Nothing. For rules whose values are not stored externally, storedValue should return Nothing.

defaultRule :: Rule key value => (key -> Maybe (Action value)) -> Rules ()

Like rule, but lower priority, if no rule exists then defaultRule is checked. All default rules must be disjoint.

rule :: Rule key value => (key -> Maybe (Action value)) -> Rules ()

Add a rule to build a key, returning an appropriate Action. All rules must be disjoint. To define lower priority rules use defaultRule.

apply :: Rule key value => [key] -> Action [value]

Execute a rule, returning the associated values. If possible, the rules will be run in parallel. This function requires that appropriate rules have been added with rule or defaultRule. All key values passed to apply become dependencies of the Action.

apply1 :: Rule key value => key -> Action value

Apply a single rule, equivalent to calling apply with a singleton list. Where possible, use apply to allow parallelism.

trackUse :: ShakeValue key => key -> Action ()

Track that a key has been used by the action preceeding it.

trackChange :: ShakeValue key => key -> Action ()

Track that a key has been changed by the action preceeding it.

trackAllow :: ShakeValue key => (key -> Bool) -> Action ()

Allow any matching key to violate the tracking rules.