external/bsd/byacc/dist/test/calc2.y

   1 /*      $NetBSD: calc2.y,v 1.1.1.5 2015/01/03 22:58:23 christos Exp $   */
   2
   3 %parse-param { int regs[26] }
   4 %parse-param { int *base }
   5
   6 %lex-param { int *base }
   7
   8 %{
   9 # include <stdio.h>
  10 # include <ctype.h>
  11
  12 #ifdef YYBISON
  13 #define YYLEX_PARAM base
  14 #define YYLEX_DECL() yylex(int *YYLEX_PARAM)
  15 #define YYERROR_DECL() yyerror(int regs[26], int *base, const char *s)
  16 int YYLEX_DECL();
  17 static void YYERROR_DECL();
  18 #endif
  19
  20 %}
  21
  22 %start list
  23
  24 %token DIGIT LETTER
  25
  26 %left '|'
  27 %left '&'
  28 %left '+' '-'
  29 %left '*' '/' '%'
  30 %left UMINUS   /* supplies precedence for unary minus */
  31
  32 %% /* beginning of rules section */
  33
  34 list  :  /* empty */
  35       |  list stat '\n'
  36       |  list error '\n'
  37             {  yyerrok ; }
  38       ;
  39
  40 stat  :  expr
  41             {  printf("%d\n",$1);}
  42       |  LETTER '=' expr
  43             {  regs[$1] = $3; }
  44       ;
  45
  46 expr  :  '(' expr ')'
  47             {  $$ = $2; }
  48       |  expr '+' expr
  49             {  $$ = $1 + $3; }
  50       |  expr '-' expr
  51             {  $$ = $1 - $3; }
  52       |  expr '*' expr
  53             {  $$ = $1 * $3; }
  54       |  expr '/' expr
  55             {  $$ = $1 / $3; }
  56       |  expr '%' expr
  57             {  $$ = $1 % $3; }
  58       |  expr '&' expr
  59             {  $$ = $1 & $3; }
  60       |  expr '|' expr
  61             {  $$ = $1 | $3; }
  62       |  '-' expr %prec UMINUS
  63             {  $$ = - $2; }
  64       |  LETTER
  65             {  $$ = regs[$1]; }
  66       |  number
  67       ;
  68
  69 number:  DIGIT
  70          {  $$ = $1; (*base) = ($1==0) ? 8 : 10; }
  71       |  number DIGIT
  72          {  $$ = (*base) * $1 + $2; }
  73       ;
  74
  75 %% /* start of programs */
  76
  77 #ifdef YYBYACC
  78 extern int YYLEX_DECL();
  79 #endif
  80
  81 int
  82 main (void)
  83 {
  84     int regs[26];
  85     int base = 10;
  86
  87     while(!feof(stdin)) {
  88         yyparse(regs, &base);
  89     }
  90     return 0;
  91 }
  92
  93 #define UNUSED(x) ((void)(x))
  94
  95 static void
  96 YYERROR_DECL()
  97 {
  98     UNUSED(regs); /* %parse-param regs is not actually used here */
  99     UNUSED(base); /* %parse-param base is not actually used here */
 100     fprintf(stderr, "%s\n", s);
 101 }
 102
 103 int
 104 YYLEX_DECL()
 105 {
 106         /* lexical analysis routine */
 107         /* returns LETTER for a lower case letter, yylval = 0 through 25 */
 108         /* return DIGIT for a digit, yylval = 0 through 9 */
 109         /* all other characters are returned immediately */
 110
 111     int c;
 112
 113     while( (c=getchar()) == ' ' )   { /* skip blanks */ }
 114
 115     /* c is now nonblank */
 116
 117     if( islower( c )) {
 118         yylval = c - 'a';
 119         return ( LETTER );
 120     }
 121     if( isdigit( c )) {
 122         yylval = (c - '0') % (*base);
 123         return ( DIGIT );
 124     }
 125     return( c );
 126 }