parsec: Monadic parser combinators
Parsec is designed from scratch as an industrial-strength parser library. It is simple, safe, well documented (on the package homepage), has extensive libraries, good error messages, and is fast. It is defined as a monad transformer that can be stacked on arbitrary monads, and it is also parametric in the input stream type.
The main entry point is the Text.Parsec module which provides
defaults for parsing Character data.
The Text.ParserCombinators.Parsec module hierarchy contains
the legacy parsec-2 API and may be removed at some point in
the future.
[Skip to Readme]
Modules
[Index] [Quick Jump]
- Text
- Text.Parsec
- ParserCombinators
- Text.ParserCombinators.Parsec
- Text.ParserCombinators.Parsec.Char
- Text.ParserCombinators.Parsec.Combinator
- Text.ParserCombinators.Parsec.Error
- Text.ParserCombinators.Parsec.Expr
- Text.ParserCombinators.Parsec.Language
- Text.ParserCombinators.Parsec.Perm
- Text.ParserCombinators.Parsec.Pos
- Text.ParserCombinators.Parsec.Prim
- Text.ParserCombinators.Parsec.Token
- Text.ParserCombinators.Parsec
Downloads
- parsec-3.1.18.0.tar.gz [browse] (Cabal source package)
- Package description (as included in the package)
Maintainer's Corner
For package maintainers and hackage trustees
Candidates
- No Candidates
| Versions [RSS] | 2.0, 2.0.0.1, 2.1.0.0, 2.1.0.1, 3.0.0, 3.0.1, 3.1.0, 3.1.1, 3.1.2, 3.1.3, 3.1.4, 3.1.5, 3.1.6, 3.1.7, 3.1.8, 3.1.9, 3.1.10, 3.1.11, 3.1.12.0, 3.1.13.0, 3.1.14.0, 3.1.15.0, 3.1.15.1, 3.1.16.0, 3.1.16.1, 3.1.17.0, 3.1.18.0 |
|---|---|
| Change log | ChangeLog.md |
| Dependencies | base (>=4.12.0.0 && <4.22), bytestring (>=0.10.8.2 && <0.13), mtl (>=2.2.2 && <2.4), text (>=1.2.3.0 && <1.3 || >=2.0 && <2.2) [details] |
| Tested with | ghc ==8.6.5 || ==8.8.4 || ==8.10.7 || ==9.0.2 || ==9.2.8 || ==9.4.8 || ==9.6.4 || ==9.8.2 || ==9.10.1 || ==9.12.1 |
| License | BSD-2-Clause |
| Author | Daan Leijen <[email protected]>, Paolo Martini <[email protected]>, Antoine Latter <[email protected]> |
| Maintainer | Oleg Grenrus <[email protected]>, Herbert Valerio Riedel <[email protected]> |
| Uploaded | by phadej at 2025-01-05T00:08:05Z |
| Category | Parsing |
| Home page | https://github.com/haskell/parsec |
| Bug tracker | https://github.com/haskell/parsec/issues |
| Source repo | head: git clone https://github.com/haskell/parsec |
| Distributions | Arch:3.1.16.1, Fedora:3.1.17.0, FreeBSD:3.1.9 |
| Reverse Dependencies | 952 direct, 14732 indirect [details] |
| Downloads | 405881 total (114 in the last 30 days) |
| Rating | 2.75 (votes: 18) [estimated by Bayesian average] |
| Your Rating | |
| Status | Docs available [build log] Last success reported on 2025-01-05 [all 1 reports] |
Readme for parsec-3.1.18.0
[back to package description]Parsec 
Please refer to the package description on Hackage for more information.
A monadic parser combinator library, written by Daan Leijen. Parsec is designed from scratch as an industrial-strength parser library. It is simple, safe, well documented, has extensive libraries, good error messages, and is fast.
Some links:
- Parsec on Hackage, contains the generated documentation.
- The 2001 paper written by Daan Leijen, some what outdated (PDF, HTML, thanks to archive.org; and PDF, thanks to Microsoft Research).
- Using Parsec, chapter 16 of Real World Haskell.
- An introduction to the Parsec library on Kunigami's blog.
- An introduction to parsing text in Haskell with Parsec on Wilson's blog.
- Differences between Parsec and Attoparsec (Haskell's other prominent parser library) as explained in an answer on StackExchange.
- Differences between Parsec and Happy (Haskell's parser generator) as explained in two answers on separate StackExchange questions (1, 2).
- Differences between Parsec and Megaparsec (an advanced fork of Parsec) as explained in Megaparsec's README.
By analyzing Parsec's reverse dependencies on Hackage we can find open source project that make use of Parsec. For example bibtex, ConfigFile, csv and hjson.
Getting started
This requires a working version of cabal and ghci, which are part of
any modern installation of Haskell, such as
Haskell Platform.
First install Parsec.
cabal install parsec
Below we show how a very simple parser that tests matching parentheses
was made from GHCI (the interactive GHC environment), which we started
with the ghci command).
Prelude> :m +Text.Parsec
Prelude Text.Parsec> let parenSet = char '(' >> many parenSet >> char ')' :: Parsec String () Char
Loading package transformers-0.3.0.0 ... linking ... done.
Loading package array-0.5.0.0 ... linking ... done.
Loading package deepseq-1.3.0.2 ... linking ... done.
Loading package bytestring-0.10.4.0 ... linking ... done.
Loading package mtl-2.1.3.1 ... linking ... done.
Loading package text-1.1.1.3 ... linking ... done.
Loading package parsec-3.1.5 ... linking ... done.
Prelude Text.Parsec> let parens = (many parenSet >> eof) <|> eof
Prelude Text.Parsec> parse parens "" "()"
Right ()
Prelude Text.Parsec> parse parens "" "()(())"
Right ()
Prelude Text.Parsec> parse parens "" "("
Left (line 1, column 2):
unexpected end of input
expecting "(" or ")"
The Right () results indicate successes: the parentheses matched.
The Left [...] result indicates a parse failure, and is detailed
with an error message.
For a more thorough introduction to Parsec we recommend the links at the top of this README file.
Contributing
Issues (bugs, feature requests or otherwise feedback) may be reported in the Github issue tracker for this project.
Pull-requests are also welcome.
License
See the LICENSE file in the repository.