[MIT-Scheme-users] queries related to list operations

[Amey Karkare]

Hi,
 I am trying to understand memory management of mit-scheme. I have
 understood a bit about how car/cdr/cons work (through Prim_car /
 Prim_cdr / Prim_cons counterparts in C). However I am having some
 difficulties in the following:

(1) When I say, at interpreter prompt:
 
   (define lst (cons 1 (cons 2 '()))

 I can see the Prim_cons function getting called, and memory being
 allocated for list '(1 2). But I cannot find out what happens when I say - 

   (define lst '(1 2))

 How and where is the memory for list '(1 2) is allocated?

(2) When I call 

    (car '(1 2 3 4))

    I see a call to Prim_car. However, I am unable to understand why
    the call to  function "list?->length" in "runtime/list.scm" which
    invokes car/cdr does NOT result in  Prim_car / Prim_cdr being
    called? Also, if I load "runtime/list.scm" in scheme interpreter
    and then call "length" - now the calls to Prim_car/Prim_cdr are
    there. 

 Please explain or give me some suggestions where to look for the
 answers to above questions.

Thanks and regards,
Amey karkare


-- 
Amey Karkare,
CSE Research Scholar,
IIT Bombay.