This package depends on the streaming library
copy 200M file divide it on lines,
adding '!' to each
lazy 0m0.813s 0m8.597s
streaming 0m0.783s 0m9.664s
pipes 0m0.771s 0m49.176s
conduit 0m1.068s 2m25.437s
This library is modeled as far as possible on the internal structure of
Data.ByteString.Lazy. There are two changes: a chunk may be delayed
by a monadic step, and the sucession of steps has a 'return' value:
data ByteString m r =
Empty r
| Chunk {-#UNPACK #-} !S.ByteString (ByteString m r)
| Go (m (ByteString m r ))
unlike
data ByteString =
Empty
| Chunk {-#UNPACK #-} !S.ByteString ByteString
That's it.
Another module is planned that would correspond more closely to
Pipes.Bytestring than to Data.ByteString.Lazy.
Producer ByteString m r as it is treated in pipes-bytestring as
the ByteString m r type is here. The result is much faster, at least
with preliminary tests. The modules integrating attoparsec and aeson
are simple replicas of k0001's pipes-attoparsec and pipes-aeson.
Also included is a replica of pipes-http.
It is possible that streaming-bytestring is conceptually clearer than
pipes-bytestring as well - and clearer than the approach taken by
conduit and io-streams. All of these are forced to integrate the
conception of an amorphous succession of bytes that may be chunked anywhere -
the direct result of, say, fromHandle, sourceFile and
the like - and a succession of 'semantically' distinct bytestrings
of interest under a single concept.
Strange as it may seem, it is arguable that the general Producer,
Source, and InputStream concepts from these libraries ought not
to hold ByteStrings except as conceptually separate units, e.g.
the lines of a document taken as strict bytestrings, where that is
legitimate. An InputStream ByteString is like an InputStream Int;
a Conduit.Source m ByteString has the same type as a Source m Int;
a Pipes.Producer ByteString m r has the same type as a Producer Int m r.
These types are suited to the general stream transformations these
libraries make possible.
We can see the strangeness in the io-streams lines
lines :: InputStream ByteString -> IO (InputStream ByteString)
and the conduit linesUnboundedAscii
linesUnboundedAscii :: (Monad m) => Conduit ByteString m ByteString
(specializing slightly). In either case, what enters on the left will
be a succession of anyhow-chunked bytes; what exits on the right will
be a succession of significant individual things of type ByteString.
What we find in IOStreams.lines and
linesUnlimitedAscii are comparable to what we would have if bytestring
defined
lines :: L.ByteString -> [S.ByteString]
or more absurdly
lines :: L.ByteString -> L.ByteString
and exposed methods for inspecting the hitherto secret chunks contained in lazy bytestrings.
The model employed by the present package is a little different. First,
the primitive lines concept is just
lines :: ByteString m r -> Stream (ByteString m) m r
as in pipes-bytestring; this corresponds precisely to
lines :: ByteString -> [ByteString]
as it appears in Data.ByteString.Lazy -- the elements of the list (stream) are
themselves lazy bytestrings.
But pipes-bytestring attempts to mean by Producer ByteString m r
what we express by ByteString m r - the undifferentiated byte stream.
But (we are provisionally suggesting) that isn't what Producer ByteString m r
means, and this is part of the reason why pipes-bytestring is difficult
for people to grasp. The user frequently proposes to inspect and work
with individual lines with Pipes themselves and thus needs
produceLines :: Producer ByteString m r -> Producer ByteString m r
produceLines = folds B.concat B.empty id . view Pipes.ByteString.lines
Here we would instead write a
produceLines :: ByteString m r -> Stream (Of ByteString) m r
which is transparently related to the type of lines itself
lines :: ByteString m r -> Stream (ByteString m) m r
The distinctive type of produceLines clearly express the transition
from the world of amorphously chunked bytestreams to the world of
significant individual values, in this case individual strict bytestrings.