"Pascal J. Bourguignon" <p...@informatimago.com> wrote in message
news:877hi1iq2o....@kuiper.lan.informatimago.com...
"BartC" <b...@freeuk.com> writes:
(defun fib (n)
(if (< n 2)
n
(+ n (fib (- n 1)) (fib (- n 2)) )
))
But it gave the wrong results and it took ages to figure out why. Even
I thought you were saying that Lisp (and dynamic typing in general)
was better for pointing out errors? The above error in C would have
been picked up more easily I think (due to less parentheses clutter,
and more obvious separators between terms).
There are more parentheses in C (you must take into account {} and []
too, and <> in C++), and the additionnal separators in C are clutter.
I mentioned 'C' because it's one of the cross-posted languages; I normally
use my own language. Nevertheless, both of these (as well as Python and
probably many others) require no more than 4 parentheses in the line in
question; the Lisp line above uses 12 (including the 2 I moved to the next
line for clarity).
And needing an extra "+" when you want to add 3 things instead of 2, sort of
makes it obvious that you do have 3 things instead of 2... In fact the error
would never have got so far. Sometimes redundancy in syntax is useful.
As for speed, executing fib(38) took about 60 seconds on my machine
(gnu clisp with no switches set).
Yes, you choosed the ONLY CL implementation having an interpreter by
default, and which when compiling, compiles to a virtual machine. This
happens also to be my favorite CL implementation, which tells you how
much I care about those silly time benchmarks.
Well, 60 seconds is pretty slow even for an interpreter; even plain CPython
took only 30 seconds.
If you want to try a CL implementation generating faster code, try SBCL.
OK.
--
Bartc
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