Darcs.Patch.Permutations

Documentation

removeFL :: (MyEq p, Commute p) => p wX wY -> FL p wX wZ -> Maybe (FL p wY wZ)

removeFL x xs removes x from xs if x can be commuted to its head. Otherwise it returns Nothing

removeRL :: (MyEq p, Commute p) => p wY wZ -> RL p wX wZ -> Maybe (RL p wX wY)

removeRL is like removeFL except with RL

removeCommon :: (MyEq p, Commute p) => (FL p :\/: FL p) wX wY -> (FL p :\/: FL p) wX wY

commuteWhatWeCanFL :: Commute p => (p :> FL p) wX wY -> (FL p :> (p :> FL p)) wX wY

commuteWhatWeCanRL :: Commute p => (RL p :> p) wX wY -> (RL p :> (p :> RL p)) wX wY

genCommuteWhatWeCanRL :: Commute p => (forall wA wB. (p :> q) wA wB -> Maybe ((q :> p) wA wB)) -> (RL p :> q) wX wY -> (RL p :> (q :> RL p)) wX wY

genCommuteWhatWeCanFL :: Commute q => (forall wA wB. (p :> q) wA wB -> Maybe ((q :> p) wA wB)) -> (p :> FL q) wX wY -> (FL q :> (p :> FL q)) wX wY

partitionFL

Arguments

:: Commute p

=> (forall wU wV. p wU wV -> Bool)

predicate; if true we would like the patch in the "left" list

-> FL p wX wY

input FL

-> (FL p :> (FL p :> FL p)) wX wY

"left", "middle" and "right"

split an FL into "left" and "right" lists according to a predicate p, using commutation as necessary. If a patch does satisfy the predicate but cannot be commuted past one that does not satisfy the predicate, it goes in the "middle" list; to sum up, we have: all p left and all (not.p) right, while midddle is mixed. Note that p should be invariant under commutation (i.e. if x1 can commute to x2 then 'p x1 = p x2').

partitionRL

Arguments

:: Commute p

=> (forall wU wV. p wU wV -> Bool)

predicate; if true we would like the patch in the "right" list

-> RL p wX wY

input RL

-> (RL p :> RL p) wX wY

"left" and "right" results

split an RL into "left" and "right" lists according to a predicate, using commutation as necessary. If a patch does satisfy the predicate but cannot be commuted past one that does not satisfy the predicate, it goes in the "left" list.

simpleHeadPermutationsFL :: Commute p => FL p wX wY -> [FL p wX wY]

This is a minor variant of headPermutationsFL with each permutation is simply returned as a FL

headPermutationsRL :: Commute p => RL p wX wY -> [RL p wX wY]

headPermutationsRL is like headPermutationsFL, except that we operate on an RL (in other words, we are pushing things to the end of a patch sequence instead of to the beginning).

headPermutationsFL :: Commute p => FL p wX wY -> [(p :> FL p) wX wY]

headPermutationsFL p:>:ps returns all the permutations of the list in which one element of ps is commuted past p

Suppose we have a sequence of patches

 X h a y s-t-c k

Suppose furthermore that the patch c depends on t, which in turn depends on s. This function will return

X :> h a y s t c k
h :> X a y s t c k
a :> X h y s t c k
y :> X h a s t c k
s :> X h a y t c k
k :> X h a y s t c

removeSubsequenceFL :: (MyEq p, Commute p) => FL p wA wB -> FL p wA wC -> Maybe (FL p wB wC)

removeSubsequenceFL ab abc returns Just c' where all the patches in ab have been commuted out of it, if possible. If this is not possible for any reason (the set of patches ab is not actually a subset of abc, or they can't be commuted out) we return Nothing.

removeSubsequenceRL :: (MyEq p, Commute p) => RL p wAb wAbc -> RL p wA wAbc -> Maybe (RL p wA wAb)

removeSubsequenceRL is like removeSubsequenceFL except that it works on RL

partitionConflictingFL :: (Commute p1, Invert p1) => CommuteFn p1 p2 -> FL p1 wX wY -> p2 wX wZ -> (FL p1 :> FL p1) wX wY

Partition a list into the patches that merge with the given patch and those that don't (including dependencies)

inverseCommuter :: (Invert p, Invert q) => CommuteFn p q -> CommuteFn q p