# Like "deriving Read" but faster?

**URL:** <https://discourse.haskell.org/t/like-deriving-read-but-faster/14585>\
**Category:** Learn\
**Created:** [August 19, 2026, 2:59pm UTC](https://discourse.haskell.org/t/like-deriving-read-but-faster/14585 "2026-08-19T14:59:21Z")\
**Posts on this page:** 1\
**Showing post:** 2

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**Author:** ![jaror](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.haskell.org/jaror/32/3271_2.png) [@jaror](https://discourse.haskell.org/u/jaror)\
**Post date:** [August 19, 2026, 3:17pm UTC](https://discourse.haskell.org/t/like-deriving-read-but-faster/14585/2 "2026-08-19T15:17:12Z")

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Constant space parsing is hard with any Haskell library. See previous discussion: [Memory usage for Backtracking in Infinite Stream Parsing](https://discourse.haskell.org/t/memory-usage-for-backtracking-in-infinite-stream-parsing/1384)

(That’s not to say that I’m very happy with the solution I posted there. uu-parsinglib is a quite exotic library and also not very performant.)

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