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- // Push expression factors onto the stack. For example...
- //
- // Input
- //
- // 2
- // 3x + 2x + 1
- //
- // Output on stack
- //
- // [ 3 ]
- // [ x^2 ]
- // [ 2 ]
- // [ x ]
- // [ 1 ]
- //
- // but not necessarily in that order. Returns the number of factors.
- #include "stdafx.h"
- #include "defs.h"
- // Local U *p is OK here because no functional path to garbage collector.
- int
- factors(U *p)
- {
- int h = tos;
- if (car(p) == symbol(ADD)) {
- p = cdr(p);
- while (iscons(p)) {
- push_term_factors(car(p));
- p = cdr(p);
- }
- } else
- push_term_factors(p);
- return tos - h;
- }
- // Local U *p is OK here because no functional path to garbage collector.
- void
- push_term_factors(U *p)
- {
- if (car(p) == symbol(MULTIPLY)) {
- p = cdr(p);
- while (iscons(p)) {
- push(car(p));
- p = cdr(p);
- }
- } else
- push(p);
- }
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