Comments for Inadvertent incorrectness

Comment on Recursive Descent Parsers in C# by Ken

Ken — Sun, 08 Nov 2009 14:52:59 +0000

Great idea.

I’ll put the code on github in the near future.

Comment on Recursive Descent Parsers in C# by Shannon Braun

Shannon Braun — Fri, 06 Nov 2009 19:10:22 +0000

Thought your notes were great. Did you ever publish the code as a project that could be downloaded. I have looked and can’t find it. Thanks.

Comment on I Am Going to JAOO 2008 As A F# Expert by Ken

Ken — Fri, 19 Sep 2008 10:46:24 +0000

Hi Robert.

Yes, I saw in your blog that you’re coming to JAOO. Unfortunately, I’ll miss your talk, because I can only participate on Monday and Tuesday.

Looking forward to see you.

Cheers,

–Ken

Comment on I Am Going to JAOO 2008 As A F# Expert by Robert Pickering

Robert Pickering — Fri, 12 Sep 2008 10:59:57 +0000

Hey I too will be attending JAOO.dk to talk about F#. Look forward to seeing you there.

Cheers,
Rob

Comment on Review: The Inmates are Running the Asylum by Martin

Martin — Sun, 13 Jan 2008 14:57:02 +0000

@Andre Bar’yudin

By reading your comment I conclude that you especially need to read that book. You obviously didn’t get the point…

Comment on Recursive Descent Parsers in C# by Thomas

Thomas — Thu, 10 Jan 2008 16:49:10 +0000

Thank you for your comprehensible yet succinct note.
I am certain it will prove helpful in my upcoming RDP project!

Comment on Recursive Descent Parsers in C# by Clifton

Clifton — Sat, 01 Dec 2007 02:11:40 +0000

I much appreciated your note. I have been looking for something like this because I’m working on a scripting language for a client’s application, implemented in C#; however, it’s built on a very messy ad-hoc parser and while I’ve fixed some bugs, I expect there are likely more. I had been defining an EBNF grammar for it, and was planning on converting it to an RDP by hand, but I’ll certainly take a good close look at your work because it would eliminate a big chunk of tedious hand-coding.

Comment on Decoding Morse Code With F# Comprehensions by Don Syme

Don Syme — Fri, 16 Nov 2007 19:50:43 +0000

Hi Ken,

Nice code! I’m glad you spotted the sequence expression optimization: that’s very nice.

With regard to performance: we’ve tracked this as bug 1253 in our internal database. The issue has been resolved and the optimizations will be available in the next release. You should see substantial improvements across the board here.

After the optimziations are made the sample code as written becomes dominated by string allocations, and hence the performance is not really a language issue: it becomes more to do with string representations and allocation rates. For example your use of Unicode strings here will mean you pay extra, and perhaps byte strings should be used instead. But as you know the algorithm has room for improvement because of over-allocation.

With regard to sequence expressions, the ideal implementation is to generate C#-style iterator classes. That is something we expect to do at some point: it means certain very elegant sequence expressions will execute extremely efficiently. However, the current performance profile of sequence expressions is good for most applications.

Kind regards
Don

Comment on Decoding Morse Code With F# Comprehensions by Ken

Ken — Mon, 12 Nov 2007 21:45:53 +0000

Hi Robert,

I have added links to the python version and the two F# versions I have used.

Note that, I do know that the algorithm that all versions of the program uses is not optimal. It would, for instance, be better to generate the solutions backwards. So that suffixes for strings that starts with A or ET, for instance, is only generated once.

Let me know your findings.

Cheers,

–Ken

Comment on Decoding Morse Code With F# Comprehensions by Robert Pickering

Robert Pickering — Sat, 10 Nov 2007 16:23:17 +0000

Hi Ken,

I’d be interested in having the test data you used, it would be difficult to tune the F# program with out this.

Thanks,
Rob