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2 points by applepie 5873 days ago | link | parent

Spirit of Lisp?

Lisp is what you want it to be, not pg's fundamentalist view on it.

6 points by absz 5873 days ago | link

That's not quite true. You would not see Lisp code written as though it were assembly, full of gotos and working with a finite number of registers, to take an extreme example. Lisp is a multiparadigm language, but it is heavily functional. As such, writing imperative code is not generally advisable ("not in the spirit of Lisp"), but is possible. Similarly, code with such a heavy use of variables is likely unfunctional, and thus would similarly be outside the "spirit of Lisp". Yes, you can do anything you want in Lisp (cf. the Church-Turing thesis), but it may not be advisable ("in the spirit of Lisp"). Again, for instance, if you want to work in a stack-based manner, it would probably be advisable to either (1) rework your code, or (2) switch to a stack-based language like Factor.

This is not unique to Lisp: if you want to write a tail-recursive, functional, list-based program in C, that's probably not a good idea. You can, but since C is optimized for iteration (with many implementations not even supporting tail call elimination) and for imperative programming (it lacks closures and anonymous functions), and since memory management in C is…clunky…you would be better off (1) reworking your code, or (2) switching to a more functional language with lists and tail call elimination, such as a Lisp.

In short, yes, as a Turing-complete language, Lisp can do anything. And as a multi-paradigm language (with macros), it can do a good job at performing a given task in any way. But it has strengths, inclinations, and intentions, which together do comprise what could be called a "spirit of Lisp".


5 points by almkglor 5873 days ago | link

> Lisp is what you want it to be, not pg's fundamentalist view on it.

The Turing Machine can be anything you want it to be, but it's not always easy - or desirable - to force the machine into doing what you want.

You can use hedge clippers to cut your toenails, but I doubt you'd want to do that.