Don Syme blogs about taking F# forward, which means, it seems, that F# will leave the confines of MS Research and be fully integrated into Visual Studio, as a product. If this is right, it's a great step for F# as a language and for functional programming in general, as we'll have a first-class IDE, by a major vendor, shipping with a functional programming language.
F# is already a great language to use, so I look forward to it getting still greater. The next step for Microsoft is to embrace Visual Haskell and fully integrate Haskell in Visual Studio too :)
Wednesday, October 17, 2007
Monday, September 24, 2007
Review: OCaml for Scientists
When we think about what makes a programming book good, what separates a classic from a run-of-the-mill for-dummies-learn-in-X-days book, it's not hard to get to the conclusion that the examples are an important piece of what we perceive as quality. I would say that this is even more so for books on programming languages: K&R had great examples; Practical Common Lisp has great examples that are now being copied by many authors; the list could go on.
So it was not that surprising to discover that one of the reasons of all the praise received by Dr. Jon Harrop's book OCaml for Scientists is its set of examples. There are even two entire chapters devoted to examples, the first for simple and the second for more significative ones. They are really good: well-chosen, interesting and well-written. Most of them have a scientific flavor, in keeping with the book's title, but to me this is a plus. Also, I don't recall seeing wavelet transforms as examples in a programming language book before; originality also counts.
The book's title is accurate: it is a book about OCaml primarily targeted for scientific applications. But most of the topics covered are really useful to anyone wanting to learn the OCaml language. Of all the ten chapters, I would say only one -- Chapter 4, Numerical Analysis -- is mostly directed to scientists. Well, probably game programmers too. And programmers of computer graphics applications, and anyone using floating-point arithmetic. Anyway, the other chapters that have somewhat of a scientific bent are: Chapter 6, Visualization, which is really about how to use OpenGL and GLUT in OCaml, which is quite cool in itself; and Chapter 10, Complete Examples, but each example is well explained and can be (mostly) understood without previous knowledge.
To give some idea about the book's contents, here is a quick tour: Chapter 1 is a quick introduction, covering most important concepts of the core language. Chapter 2 is about how to structure bigger programs, including function nesting, modules, objects, and how to manage dependencies and compilation. Chapter 3 is a very interesting chapter on data structures in OCaml, beginning with a section on algorithmic complexity; it covers the more important containers provided in the library, and also how to implement and work with trees. Chapter 4 is the one about numerical analysis, covering the basics about doing calculations with limited-precision numbers, and how to use more precise forms of arithmetic. Chapter 5 tackles input and output in OCaml, going beyond the call of duty to present the lexer generator (ocamllex) and parser generator (ocamlyacc) in the OCaml toolset. Chapter 6 is about visualization with OpenGL and GLUT, Chapter 7 is a very good one about optimization, and Chapter 8 a very useful one about libraries. The final two chapters have examples, and don't be fooled by the title of Chapter 9, Simple Examples. There is good stuff there. There are also two appendices, about more advanced features and troubleshooting advice respectivelly.
To be fair, the book has some small weaknesses that, in the end, are not that important, if you consider its target audience and what's common OCaml style. One is the treatment of objects: it is very cursory, and one of the examples (about real and complex numbers) could easily be considered a bad case of OO design. Considering most OCaml programmers rarely use objects, this is not so troubling. The other weakness I'd like to cite is more of a wish from my part: I wish there were more about advanced topics, especially functors (only very lightly touched in Appendix A).
But it's really a very good book about OCaml, both for beginners and for people with some previous exposure to it. It has advice on good programming style throughout, great examples (shown in color, properly syntax-highlighted), and distilled practical experience on some important topics (optimization, using libraries) that is hard to get elsewhere. It is remarkable not only in the very restricted universe of OCaml books, but as a programming book, in general: it stands between the best I've seen.
So it was not that surprising to discover that one of the reasons of all the praise received by Dr. Jon Harrop's book OCaml for Scientists is its set of examples. There are even two entire chapters devoted to examples, the first for simple and the second for more significative ones. They are really good: well-chosen, interesting and well-written. Most of them have a scientific flavor, in keeping with the book's title, but to me this is a plus. Also, I don't recall seeing wavelet transforms as examples in a programming language book before; originality also counts.
The book's title is accurate: it is a book about OCaml primarily targeted for scientific applications. But most of the topics covered are really useful to anyone wanting to learn the OCaml language. Of all the ten chapters, I would say only one -- Chapter 4, Numerical Analysis -- is mostly directed to scientists. Well, probably game programmers too. And programmers of computer graphics applications, and anyone using floating-point arithmetic. Anyway, the other chapters that have somewhat of a scientific bent are: Chapter 6, Visualization, which is really about how to use OpenGL and GLUT in OCaml, which is quite cool in itself; and Chapter 10, Complete Examples, but each example is well explained and can be (mostly) understood without previous knowledge.
To give some idea about the book's contents, here is a quick tour: Chapter 1 is a quick introduction, covering most important concepts of the core language. Chapter 2 is about how to structure bigger programs, including function nesting, modules, objects, and how to manage dependencies and compilation. Chapter 3 is a very interesting chapter on data structures in OCaml, beginning with a section on algorithmic complexity; it covers the more important containers provided in the library, and also how to implement and work with trees. Chapter 4 is the one about numerical analysis, covering the basics about doing calculations with limited-precision numbers, and how to use more precise forms of arithmetic. Chapter 5 tackles input and output in OCaml, going beyond the call of duty to present the lexer generator (ocamllex) and parser generator (ocamlyacc) in the OCaml toolset. Chapter 6 is about visualization with OpenGL and GLUT, Chapter 7 is a very good one about optimization, and Chapter 8 a very useful one about libraries. The final two chapters have examples, and don't be fooled by the title of Chapter 9, Simple Examples. There is good stuff there. There are also two appendices, about more advanced features and troubleshooting advice respectivelly.
To be fair, the book has some small weaknesses that, in the end, are not that important, if you consider its target audience and what's common OCaml style. One is the treatment of objects: it is very cursory, and one of the examples (about real and complex numbers) could easily be considered a bad case of OO design. Considering most OCaml programmers rarely use objects, this is not so troubling. The other weakness I'd like to cite is more of a wish from my part: I wish there were more about advanced topics, especially functors (only very lightly touched in Appendix A).
But it's really a very good book about OCaml, both for beginners and for people with some previous exposure to it. It has advice on good programming style throughout, great examples (shown in color, properly syntax-highlighted), and distilled practical experience on some important topics (optimization, using libraries) that is hard to get elsewhere. It is remarkable not only in the very restricted universe of OCaml books, but as a programming book, in general: it stands between the best I've seen.
Tuesday, August 21, 2007
Monads in OCaml
So, there. Someone who has never programmed in Haskell probably never encountered the idea of monads -- unless it is someone who works in semantics and has read Moggi's works; but I digress. An interesting way to tackle the idea of monads is to look at them outside of Haskell, and see how it works in other languages. Often, other languages don't have what it takes to express the concept of a monad in its full generality, but specific monads can always be implemented. In this regard, there's this page by oleg, and there's this other one about monads in Ruby. I remember seeing somewhere a page that compiled monad implementations in various languages, but I can't seem to find it now.
Anyhow, Brian Hurt has written a very nice tutorial about monads in OCaml. It uses the module system and functors (see comments) to define a reasonably general monad concept in OCaml. It's a good read.
Anyhow, Brian Hurt has written a very nice tutorial about monads in OCaml. It uses the module system and functors (see comments) to define a reasonably general monad concept in OCaml. It's a good read.
Tuesday, August 7, 2007
Towards Global Domination
If you haven't yet seen them or heard about them somewhere else, it seems that the videos of Simon Peyton-Jones' talks at OSCON are quite a hit.
And people still look at me funny when I say that functional programming is going to take over the world.
And people still look at me funny when I say that functional programming is going to take over the world.
Friday, July 13, 2007
Battle of the OCaml plugins for Eclipse
A new OCaml plugin for Eclipse, called OcaIDE, has just been announced. Apparently, it has been under development for a long time. It seems to be quite complete in features, although I didn't try it yet. The question is that this is the third OCaml plugin being developed currently; there's ODT, about which I talked in a earlier post, and another one being developed as one of the OCaml projects in the Google Summer of Code. The competition is good in some ways, but on the other hand the resulting fragmentation can be a problem to a small community like that of OCaml. It would be best if the teams managed to combine their efforts in some way. Let's see how this plays out.
Speaking of collaboration, there's mention on OcaIDE's site about a free-software license, but the source code doesn't seem to be available.
UPDATE: As someone pointed in the comments, the source is available together with the plugin. See here.
Speaking of collaboration, there's mention on OcaIDE's site about a free-software license, but the source code doesn't seem to be available.
UPDATE: As someone pointed in the comments, the source is available together with the plugin. See here.
Thursday, July 5, 2007
Review: Practical OCaml
Executive summary: this is not Practical Common Lisp for OCaml. It's ambitious but disappointing. However, it's not so bad as it seems at first sight.
OCaml is a sexy language that combines the expressiveness and terseness of scripting languages with the static type checking and performance of languages like C++ and Java. A book may be a good investment to learn a new language, and this is one of the few books available on the language. How does it fare?
This book has received very harsh criticism overall, and it mostly deserves it; it is somewhat of a mess. But it is not uniformly bad: some chapters are very bad, others are acceptable or interesting, depending on your background. The problem seems to be that the worst chapters come first; although it shows signs of bad editing throughout, the first few chapters are especially bad. And I mean really bad: bad text, bad editing, bad examples, lots of senseless repetition, conceptual errors, using language features not yet introduced (and that go unexplained), the list goes on. Later chapters are considerably less irritating.
Clearly inspired by Peter Seibel's terrific book Practical Common Lisp, the chapters on this one are divided in two types: the ones that explain the language, and the "Practical" ones, containing extended examples. This is a great idea, and even badly executed as it may be in Practical OCaml, it still results in interesting chapters. Actually, the Practical chapters are overall better than the language ones; from them, a reader can get a real sense of using OCaml in simple but realistic projects, integrating many different libraries and tools, some of them not contained in the standard OCaml distribution. Still, the code in these chapters can be criticized for their style. For one thing, I think the author uses classes and other OO features much more often than they appear on real OCaml programs. Nonetheless, an experienced programmer could get a lot of interesting pointers from these chapters, by knowing what to salvage and what not to replicate from the code.
But the rest of the book, the OCaml chapters, are in really bad shape. They don't explain things very well, and fails miserably at the more difficult aspects of the language. The chapter on modules and functors is so bad as to be almost useless; don't try to learn about functors from this book. Camlp4, the nifty tool for metaprogramming and extension, is other subject with a bad treatment. The chapter on Threads could be improved a lot, but it still gives a general idea of how multithreaded programming in OCaml is. Again, for experienced developers, it should provide pointers for further study.
If experienced developers can get something from this book, novice ones should stay away from it. Not only is the text confusing, but there are a lot of glaring conceptual errors. Maybe some errors are to be expected from a trade book, from an author that is not an academic, but there
are things that are completely confusing. For example, this is the definition of type (page 24): "A type is a thing (or a collection of things) or value." And there is a lot more like this, unfortunately.
Overall, it has interesting parts, but surely not enough to make worth the full cover price. For experienced programmers and people already familiar with other typed functional programming languages (Haskell, F#, SML, etc), the book could serve as an initial guide for OCaml programming, but there are better alternatives around.
OCaml is a sexy language that combines the expressiveness and terseness of scripting languages with the static type checking and performance of languages like C++ and Java. A book may be a good investment to learn a new language, and this is one of the few books available on the language. How does it fare?
This book has received very harsh criticism overall, and it mostly deserves it; it is somewhat of a mess. But it is not uniformly bad: some chapters are very bad, others are acceptable or interesting, depending on your background. The problem seems to be that the worst chapters come first; although it shows signs of bad editing throughout, the first few chapters are especially bad. And I mean really bad: bad text, bad editing, bad examples, lots of senseless repetition, conceptual errors, using language features not yet introduced (and that go unexplained), the list goes on. Later chapters are considerably less irritating.
Clearly inspired by Peter Seibel's terrific book Practical Common Lisp, the chapters on this one are divided in two types: the ones that explain the language, and the "Practical" ones, containing extended examples. This is a great idea, and even badly executed as it may be in Practical OCaml, it still results in interesting chapters. Actually, the Practical chapters are overall better than the language ones; from them, a reader can get a real sense of using OCaml in simple but realistic projects, integrating many different libraries and tools, some of them not contained in the standard OCaml distribution. Still, the code in these chapters can be criticized for their style. For one thing, I think the author uses classes and other OO features much more often than they appear on real OCaml programs. Nonetheless, an experienced programmer could get a lot of interesting pointers from these chapters, by knowing what to salvage and what not to replicate from the code.
But the rest of the book, the OCaml chapters, are in really bad shape. They don't explain things very well, and fails miserably at the more difficult aspects of the language. The chapter on modules and functors is so bad as to be almost useless; don't try to learn about functors from this book. Camlp4, the nifty tool for metaprogramming and extension, is other subject with a bad treatment. The chapter on Threads could be improved a lot, but it still gives a general idea of how multithreaded programming in OCaml is. Again, for experienced developers, it should provide pointers for further study.
If experienced developers can get something from this book, novice ones should stay away from it. Not only is the text confusing, but there are a lot of glaring conceptual errors. Maybe some errors are to be expected from a trade book, from an author that is not an academic, but there
are things that are completely confusing. For example, this is the definition of type (page 24): "A type is a thing (or a collection of things) or value." And there is a lot more like this, unfortunately.
Overall, it has interesting parts, but surely not enough to make worth the full cover price. For experienced programmers and people already familiar with other typed functional programming languages (Haskell, F#, SML, etc), the book could serve as an initial guide for OCaml programming, but there are better alternatives around.
Sunday, June 17, 2007
F# Performance
There's a comparison of F# versus IronPython in Robert Pickering's blog. The results show that F# has roughly the same level of conciseness and terseness of Python, while being close in performance to C#. This is a .NET-based comparison, but it would be interesting to compare F# with CPython to see where it stands. If we are to believe this discussion on the python-dev mailing list, it seems that IronPython's performance must be comparable to CPython's, so there we have it: .NET or not, F# strikes an interesting balance in the expressiveness versus performance trade-offs.
This is also my personal experience with OCaml: performance roughly comparable to C/C++, but expressive and concise like scripting languages. It is this interesting position in the expressiveness x performance curve that makes both F# and OCaml very worthwhile languages to learn and use today.
This is also my personal experience with OCaml: performance roughly comparable to C/C++, but expressive and concise like scripting languages. It is this interesting position in the expressiveness x performance curve that makes both F# and OCaml very worthwhile languages to learn and use today.
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