ixset-typed

Efficient relational queries on Haskell sets.

LTS Haskell 22.44:0.5.1.0@rev:1
Stackage Nightly 2026-08-20:0.6
Latest on Hackage:0.6

See all snapshots ixset-typed appears in

BSD-3-Clause licensed by Andres Löh, Happstack team, HAppS LLC
Maintained by Andres Löh, Adam Gundry
This version can be pinned in stack with:ixset-typed-0.6@sha256:4e99987d84b12daffb5e3316d08e1586af4d533e855245f68209a4a628b15e35,3300

Module documentation for 0.6

This Haskell package provides a data structure of sets that are indexed by potentially multiple indices.

Sets can be created, modified, and queried in various ways.

The package is a variant of the ixset package. The ixset package makes use of run-time type information to find a suitable index on a query, resulting in possible run-time errors when no suitable index exists. In ixset-typed, the types of all indices available or tracked in the type system. Thus, ixset-typed should be safer to use than ixset, but in turn requires more GHC extensions.

At the moment, the two packages are relatively compatible. As a consequence of the more precise types, a few manual tweaks are necessary when switching from one to the other, but the interface is mostly the same. The main other differences are strictness behaviour, and the semantics of getRange and similar interval selection operators (see the Haddocks).

Changes

0.6 (2026-08-19)

  • BREAKING CHANGE to the semantics of interval selection operators (getRange, (@><), (@>=<), (@><=), (@>=<=)): if an index has multiple values, it will now be returned by interval selection only if a single value falls in the range (see #3). Previously, these operators used two ordinal lookups and rebuilt the index in between, meaning that an element would be returned by getRange if one of its index values was greater than or equal to the lower bound and a different index value was below the upper bound. If you still need the old behaviour, replace calls to these functions with the alternatives given in the Haddocks.

  • Add various new API functions:

    • Lookup: lookupIx, lookupIxMany, lookupOne

    • Bulk modification: insertSet, insertMany, deleteSet, deleteMany, deleteIxMany

    • Set operations: filter, difference, (\\\)

    • Project out indices from values of an Indexable type: project

  • Significant performance-related changes, including changes to strictness/laziness and removal of intermediate datastructures, which should generally improve performance, but may have performance downsides or lead to space leaks in some cases:

    • An IxSet is no longer always strict in the head of the IxList. This means queries are more lazy, and avoid rebuilding the first index if it is not needed. Updates continue to be strict, to prevent thunk leaks as the IxSet is updated.

    • fromSet and fromList now compute the indices lazily (but remain spine-strict in the elements).

    • The existing union and intersection set operations, and the new filter and difference, compute the indices lazily (waiting until the index is accessed, then it is computed in full). Previously union and intersection would compute the indices partially (walking the index list strictly, but then using lazy Map operations).

  • Add forceIndices, which can be used to ensure the indices are evaluated after using operations that are now lazy in the index construction.

  • Generalise @+ and @* so they work on any Foldable structure, not just lists.

  • Various documentation and performance improvements.

  • Rename Data.IxSet.Typed.Ix to Data.IxSet.Typed.Internal.Ix, change its API and add other .Internal modules. These modules should not normally be needed and are subject to change.

  • Remove various redundant constraints.

  • Limit supported versions to GHC 9.2 and later.

  • Drop dependency on syb.

0.5.1.1 (2026-07-13)

  • GHC 9.4 through to 9.14 compatibility.

0.5.1.0 (2022-05-10)

  • GHC 9.0 and 9.2 compatibility.

0.5 (2020-03-18)

  • GHC 8.8 (and possibly 8.10) compatibility.

  • safecopy-0.10 compatibility.

0.4.0.1 (2018-10-01)

  • containers-0.6 compatibility.

0.4 (2018-03-18)

  • GHC 8.4 compatibility.

  • Drop compatibility with GHC 7. GHC 8.4 introduces Semigroup as a superclass for monoid, and Semigroup is not in base prior to GHC 8. To avoid a conditional interface or a dependency on the semigroups package, we drop compatibility with GHC 7. There are not other changes in this version, so ixset-typed-0.3.1.1 remains usable with GHC 7.

0.3.1.1 (2017-08-14)

  • GHC 8.2 compatibility.

0.3.1 (2016-06-21)

  • GHC 8.0 compatibility.

0.3 (2014-07-23)

  • IxSet internals are now more strict

  • The empty method of Indexable is now called indices and has a slightly different path; to migrate your code, if you were using Template Haskell, you probably do not have to change anything. Otherwise, wherever you have an instance of Indexable that looks like this

     instance Indexable MyIndexSet MyType where  -- OLD
   empty = mkEmpty ...

    change it to

     instance Indexable MyIndexSet MyType where  -- NEW
   indices = ixList ...

0.2 (2014-04-06)

  • Add testsuite (which is a port of the ixset testsuite).

  • Cleaning up and documentation.

  • Add ‘Foldable’ and ‘NFData’ instances.

0.1.4 (2014-04-03)

  • Documentation.

0.1.3 (2014-04-02)

  • Export IsIndexOf class.

0.1.2 (2014-04-02)

  • Clean up export list.

  • Documentation.

0.1.1 (2014-04-02)

  • Clean up export list.

  • Documentation.

0.1.0.0 (2014-03-31)

  • Initial release.