[Haskell] ANNOUNCE: ParseP library 0.1

Koen Claessen koen at chalmers.se
Thu Apr 12 03:31:15 EDT 2007

Hi Twan,

You might be interested in a different implementation of the ReadP
stuff, namely my Parsek combinator library, which I made some years
ago. It tries to mimic Daan Leijen's Parsec library closely, but
instead uses the ideas behind the ReadP library.


Kind regards,

On 4/11/07, Twan van Laarhoven <twanvl at gmail.com> wrote:
> Hi,
> Mostly for fun, and to see how well it would work, I made a
> generalized/improved variant of the ReadP parser library.
> Unlike ReadP ParseP can handle any type of token, and actually generates
> error messages in case something goes wrong. It is also possible to use
> things other then a list as an input stream, for example ByteStrings.
> In addition to the unbiased choice provided by ReadP, and a 'greedy'
> choice operator similar to the behavior of Parsec (when using try),
> there is also what I call a 'soft biased' choice. This operator prefers
> the left alternative, but not if it leads to parse errors later on. For
> example
>   > runParser ((lit 'a' <<|> return ()) >> lit 'a') "a"
> will not lead to errors, while it would be an error with other biased
> choice operators.
> An obvious advantage of ParseP over Parsec is that you don't have to
> mess with 'try'. Also, all alternatives are parsed in parallel, so no
> backtracking is needed. But I have no idea how the performance would
> compare in practice.
> Also, I am not to happy about the name, does anyone has any other
> suggestions?
> Homepage: http://twan.home.fmf.nl/parsep/
> Source:   darcs get http://twan.home.fmf.nl/repos/parsep
> Haddock:  http://twan.home.fmf.nl/parsep/doc/html/
> Twan
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