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Today's Topics:
1. Partial results with megaparsec (Dmitriy Matrosov)
2. Re: Partial results with megaparsec (David McBride)
----------------------------------------------------------------------
Message: 1
Date: Mon, 28 Jun 2021 18:37:07 +0300
From: Dmitriy Matrosov <sgf....@gmail.com>
To: beginners@haskell.org
Subject: [Haskell-beginners] Partial results with megaparsec
Message-ID: <1570a77d-1f0f-86cf-25a6-cda296488...@gmail.com>
Content-Type: text/plain; charset=utf-8; format=flowed
Hi.
I've used attoparsec before and it can return 'Partial' result containing
continuation, which is able to continue parsing if provided with more input.
E.g.
> let A.Partial c1 = A.parse (A.string "mac address") "mac "; in c1
"address"
Done "" "mac address"
Does the same thing possible with megaparsec?
After looking through library API, i haven't find a way to do this.
'runParser' (which seems the only way to run megaparsec parser) fails on
incomplete (text) input.
And if that's not possible, how should i deal with chunked input?
E.g. i read from a socket with 'recv' and i don't want to read all
data at once. How can i suspend parsing for a time, read next chunk and
continue?
Thanks.
------------------------------
Message: 2
Date: Mon, 28 Jun 2021 12:46:16 -0400
From: David McBride <toa...@gmail.com>
To: The Haskell-Beginners Mailing List - Discussion of primarily
beginner-level topics related to Haskell <beginners@haskell.org>
Subject: Re: [Haskell-beginners] Partial results with megaparsec
Message-ID:
<CAN+Tr43S22AT15cWOEHfKoN1RCH3+3O=1benswhjnq5giwp...@mail.gmail.com>
Content-Type: text/plain; charset="utf-8"
Attoparsec was created specifically for streaming, thus its parsing
functions take into account that some portion of the pattern may yet to
have arrived and its combinators avoid taking input greedily
unintentionally.
It is not clear to me that megaparsec is capable of that. There is a
package attoparsec-parsec package, which reimplements parsec's combinators
in a way attoparsec can use, but I do not see a version of that for
megaparsec. You would have to write every megaparsec combinator into an
equivalent attoparsec to create such a package.
On Mon, Jun 28, 2021 at 11:37 AM Dmitriy Matrosov <sgf....@gmail.com> wrote:
> Hi.
>
> I've used attoparsec before and it can return 'Partial' result containing
> continuation, which is able to continue parsing if provided with more
> input.
> E.g.
>
> > let A.Partial c1 = A.parse (A.string "mac address") "mac "; in c1
> "address"
> Done "" "mac address"
>
> Does the same thing possible with megaparsec?
>
> After looking through library API, i haven't find a way to do this.
> 'runParser' (which seems the only way to run megaparsec parser) fails on
> incomplete (text) input.
>
> And if that's not possible, how should i deal with chunked input?
> E.g. i read from a socket with 'recv' and i don't want to read all
> data at once. How can i suspend parsing for a time, read next chunk and
> continue?
>
> Thanks.
>
> _______________________________________________
> Beginners mailing list
> Beginners@haskell.org
> http://mail.haskell.org/cgi-bin/mailman/listinfo/beginners
>
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