Data.Strict.Sequence

Fully-strict version of Data.Sequence

Unlike Data.Sequence Seq the instances of our {- haddock #1251 -} Seq are all strict as well.

You should be able to switch from the former simply by changing your module imports, and your package dependency from containers to strict-containers. If this doesn't work, please file a bug.

The documentation in the auto-generated modules have not been updated in a particularly sophisticated way, so may sound weird or contradictory. In those cases, please re-interpret such weird wording in the context of the above.

Detailed note on laziness

Seq uses internal laziness for performance; and our data structure preserves this laziness and performance in a way that retains the strictness of values. For technical details, see the source code of our patch. As a user of the data structure, what you need to know is that:

• Strictness is guaranteed when constructing containers - values added to a container are evaluated before the new, larger, container itself is evaluated.
• Laziness and performance applies when splitting or combining existing containers, whose values have already been evaluated as per the previous point.

Bugs

One known bug, is that whole-container transforms (such as fmap) are not entirely strict, since they make use of the lazy behaviour above to avoid doing work that is unnecessary (in the lazy case) to a large part of the data structure. This is possible to fix, by re-implementing all such transforms so that they force the lazy parts as well; we just haven't gotten around to it yet. (This would revert the performance back to O(n), but this is unavoidable since all such transforms on strict data structures must inherently evaluate every single element.)

Documentation

module Data.Strict.Sequence.Autogen