[gambit-list] Passing heterogenous lists

Alex Ryu ryu.alex at gmail.com
Fri Jan 30 00:52:55 EST 2009

Hello all
I have written a C program calling scheme to evaluate logical and
arithmetical expressions.  It seems to work okay for integers, but
floats have me at a loss.  Short description of problem: I have a char
buffer of known length.  I know that the first four bytes represent a
float, the second an int, the third an int, and so on.  What I would
like to do is somehow get this data into the scheme part of my
program, preferably in a list form.  One way is to use sprintf() to do
a crummy sort of conversion, put the results in a null-terminated
string, and use with-input-from-string (thanks to Marc for showing
me), but that is pretty unpleasant.  Are there any better methods?  I
was thinking about using vectors, but I can't see how that would work.
Thanks for your help
I suppose I could just pass all 120 arguments to eval_string and
list-replace?  That seems pretty tedious.  Here is more-or-less the
relevant part of what I have now

(c-define (eval-string str) (char-string) char-string "eval_string" "extern"
    (lambda () (write-to-string (eval (list-replace from to
(read-from-string str)))))))

from is a list of tokens, to is a list of values.

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