foldl-transduce: Transducers for foldl folds.

[ bsd3, control, library ] [ Propose Tags ]

Stateful transducers and streaming-preserving grouping operations for the folds in the foldl package.

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Versions [RSS] 0.0.1,,,,,,,,,,,,,,,,,,,,,,,
Change log CHANGELOG
Dependencies base (>=4 && <5), bifunctors (>=5 && <6), bytestring (>= && <0.11), comonad (>=4 && <5), containers (<0.6), foldl (>=1.1 && <2), semigroupoids (>=5.0), text (>= && <1.3), transformers (>= && <0.5) [details]
License BSD-3-Clause
Copyright 2015 Daniel Diaz
Author Daniel Diaz
Category Control
Bug tracker
Source repo head: git clone
Uploaded by DanielDiazCarrete at 2015-08-26T22:26:39Z
Distributions NixOS:
Downloads 15063 total (67 in the last 30 days)
Rating 2.0 (votes: 1) [estimated by Bayesian average]
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Status Docs available [build log]
Last success reported on 2015-10-08 [all 2 reports]

Readme for foldl-transduce-

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What's in this library?

Stateful transducers and streaming-preserving group operations for the folds in Gabriel Gonzalez's foldl package.

When to use this library?

  • When you want to wrap a stateful decoder over a Fold. An example is decoding UTF-8: the decoder must be stateful because a multi-byte character may have been split across two blocks of bytes.

  • When you want to tweak the stream of data that arrives into a Fold, but only at certain positions. Stripping whitespace at the beginning of a text stream, for example.

  • When you want to perform group operations without breaking "streaminess", similar to what pipes-group does.

Why use this library for grouping instead of pipes-group?

Grouping fold-side instead of producer-side has the advantage that, since the results are still Folds, you can combine them using Applicative.

Also, Folds can work with sources other than Producers from pipes.

Grouping fold-side has limitations as well:

  • You can't perform bracketing operations like "withFile" that span the folding of an entire group. You can do that in pipes-group.

  • You have more flexibility in pipes-group to decide how to fold a group based on previous results.