Sequence 0.1.0 Released

Sequence version 0.1.0 has been released!

http://rubyforge.org/projects/sequence
http://sequence.rubyforge.org/

Sequence is a wrapper api for accessing data in Strings, Arrays,
Files, IOs, and Enumerations. Each sequence encapsulates some
data and a current position within it. There are methods for
moving the position, reading and writing data(with or without
moving the position) forward or backward from the current
position (or anywhere at all), scanning for patterns (like
StringScanner, but it works in Files too, among others), and
saving a position that will remain valid even after data is
deleted or inserted elsewhere within the sequence.

There are also some utility classes for making sequences reversed
or circular, turning one-way sequences into two-way, buffering,
and making sequences that are subsets or aggregations of existing
sequences.

Sequence is based on Eric M.'s Cursor library. I’d like to
thank Eric for Cursor, without which Sequence would not have
existed; my design is very much a derivative of his.

known problems:
Some unit tests fail
Buffered does not work at all
Shifting’s modify methods don’t work reliably
Some write operations failing for List
No unit tests at all for array-like sequences
(tho Reg’s unit test does test OfArray at least somewhat…)

Caleb C. wrote:

position (or anywhere at all), scanning for patterns (like
StringScanner, but it works in Files too, among others), and
saving a position that will remain valid even after data is
deleted or inserted elsewhere within the sequence.

[snip]

Sounds interesting… is it better than Eric M’s Cursor
class? Different in some significant way?

Hal

On 10/6/06, Hal F. [email protected] wrote:

Sounds interesting… is it better than Eric M’s Cursor
class? Different in some significant way?

Well, Sequence is faster than Cursor for most things. I haven’t
benchmarked, but (eg) #read should be at least 10-100x faster. (Except
when reading from a file, which Cursor optimizes fairly well, if I
remember.)

I think that the support for #scan and friends (from StringScanner) is
better in Sequence. Eric will disagree with me on this.

Cursor doesn’t have an equivalent to my Sequence::Subseq.
Cursor::Linked more or less corresponds to my Sequence::List (except
that I never properly understood Cursor::Linked – how to use it, how
it works).

Those are the biggest differences. The sequence api has otherwise
about the same capabilities as its ancestor. I’ve moved everything
around to suit my way of thinking, tho, so it isn’t compatible (except
for doing very simple things).

On 10/7/06, Caleb C. [email protected] wrote:

I think that the support for #scan and friends (from StringScanner) is
for doing very simple things).

Sorry I haven’t been working on Cursor lately. I will readily admit
that
performance isn’t too great on Cursor. I was focusing on functionality
first. Unfortunately when I go back and improve performance, I’ll be
changing the API slightly. My focus for the year has been on Grammar
which
now has kick-ass performance (even faster than regexp’s when used in
conjunction with Dominick Baton’s ruby2cext). It also has some
interesting
new features (like handling left recursion in an LL(1) parser). I’ll
try to
get some of this into CVS soon at least.

Because Grammar’s are on par (can be faster) with regexp’s I’ll be
removing
regexp support from Cursor in the next release. It is just too ugly to
support in a clean way - they are too tied to String. Grammar on the
other
hand can work on anything that looks remotely like a Cursor - usually
just
#read1next will do. So, maybe it is best that Caleb made an derivative
of
Cursor since he really wanted regexp support. When I get back to
Cursor,
I’ll be improving performance quite a bit. I’ve been using C++ lately
(which I hate) and will probably be taking some of the STL ideas (i.e.
iterators, sequences, algorithms) I’ve learned over to Cursor. I think
I’ll
make it so that you can #extend some of ruby’s standard objects to look
like
a Cursor (or just #include in that class to make all of them look like
Cursor’s). That should give very good performance.

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