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Advanced programming languages

matt.might.net

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Re: Advanced programming languages

#3

Post by terra_t »

Some thoughts.

The people I know who do work in machine learning (Jon Kleinberg, Thorsten Joachims, and their students) work in straight-up C, not Haskell, as the author suggests. Most of the dominant methods used today, such as the SVM, boosting, and the dynamic programming methods used in genomics are (i) numerical more than symbolic and (ii) involve moving a LOT of data around, so you want control of your data structures. (Sometimes these guys compress in-memory pointers!)

I looked long and hard at Scala and decided that I didn't like what I saw. One problem is that, based on the JVM, type erasure is a big "broken window" that seriously damages the Scala type system. You can use generics for ~years~ in Java and never notice the problems that type erasure causes, but I find that 2/3 of the designs that I specifically want an advanced type system for do not work in Scala because of type erasure.

Another issue with Scala is that the interface with Java, particularly using collections, is awkward; people who want to work in the JVM but want concision might be happier with Groovy. Scala's Lispy-Lists are convenient for the pattern matching capabilities in Scala, but are much less efficient than the vector-based Lists that come with Java when your data gets big.

As for oCaml, the real excitement is in F#. You get the wonderful oCaml language and all of its features, plus you get an interface to the C#/.NET world that's much nicer than Scala's interface to the JVM. You've got access to the whole .NET framework base class library, plus all sorts of stuff that's been written for .NET.

I'd also put C# on the border between a "mainstream" and "advanced" language. C#'s generics implementation just added support for covariant and contravariant inheritance, which is one of the features that had me interested in Scala. C# has good lambdas, really neat stuff in LINQ, and "expression trees" which offer metaprogramming capabilities above and beyond any static language I've seen.

Note that there is a good open source implementation of the .NET framework, Mono, so you can develop in C# and F# and target Linux, MacOS and other platforms.

Re: Advanced programming languages

#4

Post by DrSprout »

>[Scheme is] untyped, which makes it ideal for web-based programming and rapid prototyping.

Erm... While Scheme can be useful for web and prototyping, it is typed. That's why R5RS requires functions like number->string and so on.

Re: Advanced programming languages

#5

Post by KirinDave »

And a strong sell for Scala and no mention of Clojure. It confuses the hell out of me; clojure is fast, mature, and has a OO syntax and model to rival CLOS. It's got built in laziness and te best concurrency primitives I've seen to date (and I was a professional Erlang programmer).

What does it take to break into the general public's consciousness? Clearly it's not the parens.

Re: Advanced programming languages

#6

Post by ekiru »

DrSprout wrote: post #4

>[Scheme is] untyped, which makes it ideal for web-based programming and rapid prototyping. Erm... While Scheme can be useful for web and prototyping, it is typed. That's why R5RS requires functions like number->string and so on.

Some people use "type" exclusively to refer to compile-time entities. By this definition, languages that are commonly referred to as "dynamically-typed" are actually "untyped", because they have only one compile-time type, which is essentially the same as having no types.

Re: Advanced programming languages

#7

Post by francoisdevlin »

KirinDave wrote: post #5

And a strong sell for Scala and no mention of Clojure. It confuses the hell out of me; clojure is fast, mature, and has a OO syntax and model to rival CLOS. It's got built in laziness and te best concurrency primitives I've seen to date (and I was a professional Erlang programmer). What does it take to break into the general public's consciousness? Clearly it's not the parens.

I seriously think Clojure is too much to take in at the first introduction. It's really hard to get your brain around everything done right, when compared to traditional programming. You need to use it for a while to really get why it's approach to state (not concurrency) is awesome.

Re: Advanced programming languages

#8

Post by Artemidoros »

terra_t wrote: post #3

Some thoughts. The people I know who do work in machine learning (Jon Kleinberg, Thorsten Joachims, and their students) work in straight-up C, not Haskell, as the author suggests. Most of the dominant methods used today, such as the SVM, boosting, and the dynamic programming methods used in genomics are (i) numerical more than symbolic and (ii) involve moving a LOT of data around, so you want control of your data str…

Note that there is a good open source implementation of the .NET framework, Mono, so you can develop in C# and F# and target Linux, MacOS and other platforms.

Is Mono actually usable with F#? The last time I checked (2 months ago) the F# plugin for MonoDevelop didn't work and the questions on how to getting it to work (by various people) went unanswered by the developer.

The runtime performance of F# code was shaky at best, the REPL had (on OS X at least) startup times to make it practically useless and without TCO the usefulness of F# really took a hit.

Not wanting to bash on Mono or F# (which is my favorite language), but writing production software with this combination is currently not something I would recommend.

Re: Advanced programming languages

#9

Post by silentbicycle »

ekiru wrote: post #6
DrSprout wrote: post #4

>[Scheme is] untyped, which makes it ideal for web-based programming and rapid prototyping. Erm... While Scheme can be useful for web and prototyping, it is typed. That's why R5RS requires functions like number->string and so on.

Some people use "type" exclusively to refer to compile-time entities. By this definition, languages that are commonly referred to as "dynamically-typed" are actually "untyped", because they have only one compile-time type, which is essentially the same as having no types.

That's confusing weak/strong with static/dynamic typing, though. (A common error.)

"What To Know Before Debating Type Systems" (http://www.pphsg.org/cdsmith/types.html) is a pretty good introduction to types.

Also, while I'm only partway through Benjamin Pierce's _Types and Programming Languages_, it's been quite good so far.

Re: Advanced programming languages

#10

Post by raganwald » 

  It has been my experience that it is difficult to get a bug passed the
  Hindley-Milner type system.
Amusingly, this typo (passed instead of past) is an example of the challenge facing language and tool developers. We can make a checking system isomorphic to a spell-checking system, but then we need a grammar-checking system to ensure that even if a word is correctly spelled, it forms a legal sentence. Once we have that, we need some sort of logic-checking system to make sure that a word with the correct spelling and the correct grammar is meaningful in the program. And so forth.

It's type-checking all the way up.

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