flatparse 0.1.0.1 → 0.1.0.2
raw patch · 2 files changed
+9/−5 lines, 2 filesPVP ok
version bump matches the API change (PVP)
API changes (from Hackage documentation)
Files
- README.md +7/−3
- flatparse.cabal +2/−2
README.md view
@@ -1,5 +1,6 @@ # flatparse +[](https://hackage.haskell.org/package/flatparse)  `flatparse` is a high-performance parsing library, focusing on __programming languages__ and __human-readable data formats__. The "flat" in the name @@ -14,10 +15,10 @@ * __Support for fast source location handling, indentation parsing and informative error messages__. `flatparse` provides a low-level interface to these. Batteries are _not included_, but it should be possible for users to build custom solutions, which are more sophisticated, but still as fast as possible. In my experience, the included batteries in other libraries often come with major unavoidable overheads, and often we still have to extend existing machinery in order to scale to production features. * The __backtracking model__ of `flatparse` is different to parsec libraries, and is more close to the [nom](https://github.com/Geal/nom) library in Rust. The idea is that _parser failure_ is distinguished from _parsing error_. The former is used for control flow, and we can backtrack from it. The latter is used for unrecoverable errors, and by default it's propagated to the top. `flatparse` does not track whether parsers have consumed inputs. In my experience, what we really care about is the failure/error distinction, and in `parsec` or `megaparsec` the consumed/non-consumed separation is often muddled and discarded in larger parser implementations. By default, basic `flatparse` parsers can fail but can not throw errors, with the exception of the specifically error-throwing operations. Hence, `flatparse` users have to be mindful about grammar, and explicitly insert errors where it is known that the input can't be valid. -`flatparse` comes in two flavors: [`FlatParse.Basic`](src/FlatParse/Basic.hs) and [`FlatParse.Stateful`](src/FlatParse/Stateful.hs). Both support a custom error type and a custom reader environment. +`flatparse` comes in two flavors: [`FlatParse.Basic`][basic] and [`FlatParse.Stateful`][stateful]. Both support a custom error type and a custom reader environment. -* [`FlatParse.Basic`](src/FlatParse/Basic.hs) only supports the above features. If you don't need indentation parsing, this is sufficient. -* [`FlatParse.Stateful`](src/FlatParse/Stateful.hs) additionally supports a built-in `Int` worth of internal state. This can support a wide range of indentation parsing features. There is a slight overhead in performance and code size compared to `Basic`. However, in small parsers and microbenchmarks the difference between `Basic` and `Stateful` is often reduced to near zero by GHC and LLVM optimization. The difference is more marked if we use native code backend instead of LLVM. +* [`FlatParse.Basic`][basic] only supports the above features. If you don't need indentation parsing, this is sufficient. +* [`FlatParse.Stateful`][stateful] additionally supports a built-in `Int` worth of internal state. This can support a wide range of indentation parsing features. There is a slight overhead in performance and code size compared to `Basic`. However, in small parsers and microbenchmarks the difference between `Basic` and `Stateful` is often reduced to near zero by GHC and LLVM optimization. The difference is more marked if we use native code backend instead of LLVM. The reason for baking a reader into the parsers, is that if we need it, it's convenient, and if we don't, then GHC very reliably optimizes unused environments away. In contrast, GHC optimizes much less reliably if we try to wrap the existing `Reader` from `transformers` around our parsers. @@ -56,3 +57,6 @@ | attoparsec | 83288 | | megaparsec | 188696 | | parsec | 75880 | + +[basic]: https://hackage.haskell.org/package/flatparse/docs/FlatParse-Basic.html +[stateful]: https://hackage.haskell.org/package/flatparse/docs/FlatParse-Stateful.html
flatparse.cabal view
@@ -4,10 +4,10 @@ -- -- see: https://github.com/sol/hpack ----- hash: 109008cec585ef59a62c27304da5072f8b80dfb2f06c001b09d9a97a5c40ffc7+-- hash: df83ba622236fe722641b9c67f9617e027392e36c25387858a3beffc734f05be name: flatparse-version: 0.1.0.1+version: 0.1.0.2 synopsis: High-performance parsing from strict bytestrings description: @Flatparse@ is a high-performance parsing library, focusing on programming languages and human-readable data formats. See the README for more information: