bake.cpp

   1 // pretty print
   2
   3 #include "stdafx.h"
   4 #include "defs.h"
   5
   6 void
   7 bake(void)
   8 {
   9         int h, s, t, x, y, z;
  10
  11         expanding++;
  12
  13         save();
  14
  15         p1 = pop();
  16
  17         s = ispoly(p1, symbol(SYMBOL_S));
  18         t = ispoly(p1, symbol(SYMBOL_T));
  19         x = ispoly(p1, symbol(SYMBOL_X));
  20         y = ispoly(p1, symbol(SYMBOL_Y));
  21         z = ispoly(p1, symbol(SYMBOL_Z));
  22
  23         if (s == 1 && t == 0 && x == 0 && y == 0 && z == 0) {
  24                 p2 = symbol(SYMBOL_S);
  25                 bake_poly();
  26         } else if (s == 0 && t == 1 && x == 0 && y == 0 && z == 0) {
  27                 p2 = symbol(SYMBOL_T);
  28                 bake_poly();
  29         } else if (s == 0 && t == 0 && x == 1 && y == 0 && z == 0) {
  30                 p2 = symbol(SYMBOL_X);
  31                 bake_poly();
  32         } else if (s == 0 && t == 0 && x == 0 && y == 1 && z == 0) {
  33                 p2 = symbol(SYMBOL_Y);
  34                 bake_poly();
  35         } else if (s == 0 && t == 0 && x == 0 && y == 0 && z == 1) {
  36                 p2 = symbol(SYMBOL_Z);
  37                 bake_poly();
  38         } else if (iscons(p1)) {
  39                 h = tos;
  40                 push(car(p1));
  41                 p1 = cdr(p1);
  42                 while (iscons(p1)) {
  43                         push(car(p1));
  44                         bake();
  45                         p1 = cdr(p1);
  46                 }
  47                 list(tos - h);
  48         } else
  49                 push(p1);
  50
  51         restore();
  52
  53         expanding--;
  54 }
  55
  56 void
  57 polyform(void)
  58 {
  59         int h;
  60
  61         save();
  62
  63         p2 = pop();
  64         p1 = pop();
  65
  66         if (ispoly(p1, p2))
  67                 bake_poly();
  68         else if (iscons(p1)) {
  69                 h = tos;
  70                 push(car(p1));
  71                 p1 = cdr(p1);
  72                 while (iscons(p1)) {
  73                         push(car(p1));
  74                         push(p2);
  75                         polyform();
  76                         p1 = cdr(p1);
  77                 }
  78                 list(tos - h);
  79         } else
  80                 push(p1);
  81
  82         restore();
  83 }
  84
  85 void
  86 bake_poly()
  87 {
  88         int h, i, k, n;
  89         U **a;
  90         a = stack + tos;
  91         push(p1);               // p(x)
  92         push(p2);               // x
  93         k = coeff();
  94         h = tos;
  95         for (i = k - 1; i >= 0; i--) {
  96                 p1 = a[i];
  97                 bake_poly_term(i);
  98         }
  99         n = tos - h;
 100         if (n > 1) {
 101                 list(n);
 102                 push(symbol(ADD));
 103                 swap();
 104                 cons();
 105         }
 106         p1 = pop();
 107         tos -= k;
 108         push(p1);
 109 }
 110
 111 // p1 points to coefficient of p2 ^ k
 112
 113 void
 114 bake_poly_term(int k)
 115 {
 116         int h, n;
 117
 118         if (iszero(p1))
 119                 return;
 120
 121         // constant term?
 122
 123         if (k == 0) {
 124                 if (car(p1) == symbol(ADD)) {
 125                         p1 = cdr(p1);
 126                         while (iscons(p1)) {
 127                                 push(car(p1));
 128                                 p1 = cdr(p1);
 129                         }
 130                 } else
 131                         push(p1);
 132                 return;
 133         }
 134
 135         h = tos;
 136
 137         // coefficient
 138
 139         if (car(p1) == symbol(MULTIPLY)) {
 140                 p1 = cdr(p1);
 141                 while (iscons(p1)) {
 142                         push(car(p1));
 143                         p1 = cdr(p1);
 144                 }
 145         } else if (!equaln(p1, 1))
 146                 push(p1);
 147
 148         // x ^ k
 149
 150         if (k == 1)
 151                 push(p2);
 152         else {
 153                 push(symbol(POWER));
 154                 push(p2);
 155                 push_integer(k);
 156                 list(3);
 157         }
 158
 159         n = tos - h;
 160
 161         if (n > 1) {
 162                 list(n);
 163                 push(symbol(MULTIPLY));
 164                 swap();
 165                 cons();
 166         }
 167 }