[GHC] #10837: Constant-time indexing of closed type family axioms
#10837: Constant-time indexing of closed type family axioms -------------------------------------+------------------------------------- Reporter: jstolarek | Owner: Type: task | Status: new Priority: low | Milestone: Component: Compiler | Version: 7.11 Keywords: | Operating System: Unknown/Multiple Architecture: | Type of failure: Compile-time Unknown/Multiple | performance bug Test Case: | Blocked By: Blocking: | Related Tickets: Differential Revisions: | -------------------------------------+------------------------------------- Right now `CoAxiom` stores a list of `CoAxBranch`es in a `BranchList`. But it would be useful to actually have a constant-time indexing into axioms. One code fragment when I really wanted to have this feature is in `TcValidity.checkValidCoAxiom`: {{{#!hs -- Replace n-th element in the list. Assumes 0-based indexing. replace_br :: [CoAxBranch] -> Int -> CoAxBranch -> [CoAxBranch] replace_br brs n br = take n brs ++ [br] ++ drop (n+1) brs }}} I believe this code could be rewritten in a much more efficient way using constant-time indexing. The new data structure should most likely have a type that indicates whether the axiom is branched or not. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/10837 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler
#10837: Constant-time indexing of closed type family axioms -------------------------------------+------------------------------------- Reporter: jstolarek | Owner: Type: task | Status: patch Priority: low | Milestone: Component: Compiler | Version: 7.11 Resolution: | Keywords: Operating System: Unknown/Multiple | Architecture: Type of failure: Compile-time | Unknown/Multiple performance bug | Test Case: Blocked By: | Blocking: Related Tickets: | Differential Revisions: Phab:D1261 -------------------------------------+------------------------------------- Changes (by goldfire): * status: new => patch * differential: => Phab:D1261 -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/10837#comment:1 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler
#10837: Constant-time indexing of closed type family axioms
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Reporter: jstolarek | Owner:
Type: task | Status: patch
Priority: low | Milestone:
Component: Compiler | Version: 7.11
Resolution: | Keywords:
Operating System: Unknown/Multiple | Architecture:
Type of failure: Compile-time | Unknown/Multiple
performance bug | Test Case:
Blocked By: | Blocking:
Related Tickets: | Differential Revisions: Phab:D1261
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Comment (by Richard Eisenberg
#10837: Constant-time indexing of closed type family axioms -------------------------------------+------------------------------------- Reporter: jstolarek | Owner: Type: task | Status: closed Priority: low | Milestone: Component: Compiler | Version: 7.11 Resolution: fixed | Keywords: Operating System: Unknown/Multiple | Architecture: Type of failure: Compile-time | Unknown/Multiple performance bug | Test Case: Blocked By: | Blocking: Related Tickets: | Differential Revisions: Phab:D1261 -------------------------------------+------------------------------------- Changes (by goldfire): * status: patch => closed * resolution: => fixed Comment: No need for a test case. Do //not// merge. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/10837#comment:3 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler
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