
Re: Mathematica and Lisp
Posted:
Jan 14, 2013 12:01 AM


On 1/12/2013 6:51 PM, David Bailey wrote: ... >> > Mathematica has a vague resemblance to LISP, but there are big > differences. One in particular, is that Mathematica lists are not linked > lists.
David has a point: to some extent Mathematica "does Lisp wrong". Lisp has lists but also arrays and hashtables. Mathematica uses the term List, but the implementation is as an array. Then there is a SparseArray which is also not an array but a hashtable. The advantage of a true list is that you can add new elements to it without copying it. The advantage of an array is that you can access the nth element without scanning through others.
Maybe it would be fairer to say that Mathematica "does data structures wrong" because it conflicts with standard usage throughout computer science.
That's one reason why I think it is questionable that people should learn Mathematica's language as a first programming language. (Another reason has to do with the terribly confusing implementation of scope in Blocks, Modules, Functions, Patterns.) But that's not pertinent to this particular question.
There is another aspect though, suggesting learning Lisp is not a bad idea. which is that some parts of Mathematica's underlying calculation engine are best accessed using a functional programming style. These include Map and friends, Apply, Function (&) and a handful of other constructs adapted and occasionally corrupted from Lisp or other functionalstyle languages.
Learning a simple version of Lisp, namely Scheme, by reading the classic Structure and Interpretation of Computer Programs (SICP) by Abelson/Sussman can be an illuminating, clarifying experience, especially for people who have been exposed to any of the traditional languages or Mathematica.
If you have ever wondered if languages like C++ or Java or PHP ... really need to be so complicated  is it inherent in programming algorithms? then you should take a look at SICP. Free online.
> I'd read the Mathematica tutorial, and forget about LISP!
I'd recommend that you too read SICP. It's deceptively easy to get into, and many people really enjoy it.
RJF

