numerator.cpp

   1 #include "stdafx.h"
   2 #include "defs.h"
   3
   4 void
   5 eval_numerator(void)
   6 {
   7         push(cadr(p1));
   8         eval();
   9         numerator();
  10 }
  11
  12 void
  13 numerator(void)
  14 {
  15         int h;
  16
  17         save();
  18
  19         p1 = pop();
  20
  21         if (car(p1) == symbol(ADD)) {
  22                 push(p1);
  23                 rationalize();
  24                 p1 = pop();
  25         }
  26
  27         if (car(p1) == symbol(MULTIPLY)) {
  28                 h = tos;
  29                 p1 = cdr(p1);
  30                 while (iscons(p1)) {
  31                         push(car(p1));
  32                         numerator();
  33                         p1 = cdr(p1);
  34                 }
  35                 multiply_all(tos - h);
  36         } else if (isrational(p1)) {
  37                 push(p1);
  38                 mp_numerator();
  39         } else if (car(p1) == symbol(POWER) && isnegativeterm(caddr(p1)))
  40                 push(one);
  41         else
  42                 push(p1);
  43
  44         restore();
  45 }
  46
  47 #if SELFTEST
  48
  49 static char *s[] = {
  50
  51         "numerator(2/3)",
  52         "2",
  53
  54         "numerator(x)",
  55         "x",
  56
  57         "numerator(1/x)",
  58         "1",
  59
  60         "numerator(a+b)",
  61         "a+b",
  62
  63         "numerator(1/a+1/b)",
  64         "a+b",
  65 };
  66
  67 void
  68 test_numerator(void)
  69 {
  70         test(__FILE__, s, sizeof s / sizeof (char *));
  71 }
  72
  73 #endif