projects / unix-history / blame
| Commit | Line | Data |
|---|---|---|
| fc670973 PK |
1 | static char *sccsid = "@(#)rval.c 1.1 (Berkeley) %G%"; |
| 2 | /* Copyright (c) 1979 Regents of the University of California */ | |
| 3 | # | |
| 4 | /* | |
| 5 | * pxp - Pascal execution profiler | |
| 6 | * | |
| 7 | * Bill Joy UCB | |
| 8 | * Version 1.2 January 1979 | |
| 9 | */ | |
| 10 | ||
| 11 | #include "0.h" | |
| 12 | #include "tree.h" | |
| 13 | ||
| 14 | extern char *opnames[]; | |
| 15 | ||
| 16 | #define alph(c) ((c >= 'a' && c <= 'z') || (c >= 'A' && c <= 'Z')) | |
| 17 | /* | |
| 18 | * Rvalue reformats an expression. | |
| 19 | * Par is a flag indicating that the expression | |
| 20 | * should be parenthesized if it is non-atomic. | |
| 21 | */ | |
| 22 | rvalue(r, par) | |
| 23 | register int *r; | |
| 24 | int par; | |
| 25 | { | |
| 26 | register int *al; | |
| 27 | register char *opname; | |
| 28 | ||
| 29 | if (r == NIL) { | |
| 30 | ppid("{expr}"); | |
| 31 | return; | |
| 32 | } | |
| 33 | if (r[0] <= T_IN) | |
| 34 | opname = opnames[r[0]]; | |
| 35 | switch (r[0]) { | |
| 36 | case T_BINT: | |
| 37 | case T_INT: | |
| 38 | case T_FINT: | |
| 39 | ppnumb(r[2]); | |
| 40 | if (r[0] == T_BINT) | |
| 41 | ppsep("b"); | |
| 42 | return; | |
| 43 | case T_NIL: | |
| 44 | ppkw("nil"); | |
| 45 | return; | |
| 46 | case T_FCALL: | |
| 47 | funccod(r); | |
| 48 | return; | |
| 49 | case T_VAR: | |
| 50 | lvalue(r); | |
| 51 | return; | |
| 52 | case T_CSET: | |
| 53 | cset(r); | |
| 54 | return; | |
| 55 | case T_STRNG: | |
| 56 | ppstr(r[2]); | |
| 57 | return; | |
| 58 | } | |
| 59 | if (par) | |
| 60 | ppbra("("); | |
| 61 | switch (r[0]) { | |
| 62 | default: | |
| 63 | panic("rval"); | |
| 64 | case T_PLUS: | |
| 65 | case T_MINUS: | |
| 66 | ppop(r[0] == T_PLUS ? "+" : "-"); | |
| 67 | al = r[2]; | |
| 68 | rvalue(r[2], prec(al) > prec(r) || full); | |
| 69 | break; | |
| 70 | case T_NOT: | |
| 71 | ppkw(opname); | |
| 72 | ppspac(); | |
| 73 | rvalue(r[2], 1); | |
| 74 | break; | |
| 75 | case T_EQ: | |
| 76 | case T_NE: | |
| 77 | case T_GE: | |
| 78 | case T_LE: | |
| 79 | case T_GT: | |
| 80 | case T_LT: | |
| 81 | al = r[2]; | |
| 82 | rvalue(al, prec(al) <= prec(r) || full); | |
| 83 | goto rest; | |
| 84 | case T_AND: | |
| 85 | case T_OR: | |
| 86 | case T_MULT: | |
| 87 | case T_ADD: | |
| 88 | case T_SUB: | |
| 89 | case T_DIVD: | |
| 90 | case T_MOD: | |
| 91 | case T_DIV: | |
| 92 | case T_IN: | |
| 93 | al = r[2]; | |
| 94 | rvalue(al, prec(al) < prec(r) || full); | |
| 95 | rest: | |
| 96 | ppspac(); | |
| 97 | if (alph(opname[0])) | |
| 98 | ppkw(opname); | |
| 99 | else | |
| 100 | ppop(opname); | |
| 101 | ppspac(); | |
| 102 | al = r[3]; | |
| 103 | rvalue(al, prec(al) <= prec(r) || full); | |
| 104 | break; | |
| 105 | } | |
| 106 | if (par) | |
| 107 | ppket(")"); | |
| 108 | } | |
| 109 | ||
| 110 | /* | |
| 111 | * Prec returns the precedence of an operator, | |
| 112 | * with larger numbers indicating stronger binding. | |
| 113 | * This is used to determine when parenthesization | |
| 114 | * is needed on subexpressions. | |
| 115 | */ | |
| 116 | prec(r) | |
| 117 | register int *r; | |
| 118 | { | |
| 119 | ||
| 120 | if (r == NIL) | |
| 121 | return; | |
| 122 | switch (r[0]) { | |
| 123 | case T_NOT: | |
| 124 | return (3); | |
| 125 | case T_MULT: | |
| 126 | case T_DIVD: | |
| 127 | case T_DIV: | |
| 128 | case T_MOD: | |
| 129 | case T_AND: | |
| 130 | return (2); | |
| 131 | case T_ADD: | |
| 132 | case T_SUB: | |
| 133 | case T_OR: | |
| 134 | case T_PLUS: | |
| 135 | case T_MINUS: | |
| 136 | return (1); | |
| 137 | default: | |
| 138 | return (0); | |
| 139 | } | |
| 140 | } |