external/bsd/byacc/dist/test/calc3.y

   1 /*      $NetBSD: calc3.y,v 1.1.1.4 2013/04/06 14:45:28 christos Exp $   */
   2
   3 %pure-parser
   4
   5 %parse-param { int regs[26] }
   6 %parse-param { int *base }
   7
   8 %lex-param { int *base }
   9
  10 %{
  11 # include <stdio.h>
  12 # include <ctype.h>
  13
  14 #ifdef YYBISON
  15 #define YYSTYPE int
  16 #define YYLEX_PARAM base
  17 #define YYLEX_DECL() yylex(YYSTYPE *yylval, int *YYLEX_PARAM)
  18 #define YYERROR_DECL() yyerror(int regs[26], int *base, const char *s)
  19 int YYLEX_DECL();
  20 static void YYERROR_DECL();
  21 #endif
  22
  23 %}
  24
  25 %start list
  26
  27 %token DIGIT LETTER
  28
  29 %left '|'
  30 %left '&'
  31 %left '+' '-'
  32 %left '*' '/' '%'
  33 %left UMINUS   /* supplies precedence for unary minus */
  34
  35 %% /* beginning of rules section */
  36
  37 list  :  /* empty */
  38       |  list stat '\n'
  39       |  list error '\n'
  40             {  yyerrok ; }
  41       ;
  42
  43 stat  :  expr
  44             {  printf("%d\n",$1);}
  45       |  LETTER '=' expr
  46             {  regs[$1] = $3; }
  47       ;
  48
  49 expr  :  '(' expr ')'
  50             {  $$ = $2; }
  51       |  expr '+' expr
  52             {  $$ = $1 + $3; }
  53       |  expr '-' expr
  54             {  $$ = $1 - $3; }
  55       |  expr '*' expr
  56             {  $$ = $1 * $3; }
  57       |  expr '/' expr
  58             {  $$ = $1 / $3; }
  59       |  expr '%' expr
  60             {  $$ = $1 % $3; }
  61       |  expr '&' expr
  62             {  $$ = $1 & $3; }
  63       |  expr '|' expr
  64             {  $$ = $1 | $3; }
  65       |  '-' expr %prec UMINUS
  66             {  $$ = - $2; }
  67       |  LETTER
  68             {  $$ = regs[$1]; }
  69       |  number
  70       ;
  71
  72 number:  DIGIT
  73          {  $$ = $1; (*base) = ($1==0) ? 8 : 10; }
  74       |  number DIGIT
  75          {  $$ = (*base) * $1 + $2; }
  76       ;
  77
  78 %% /* start of programs */
  79
  80 #ifdef YYBYACC
  81 extern int YYLEX_DECL();
  82 #endif
  83
  84 int
  85 main (void)
  86 {
  87     int regs[26];
  88     int base = 10;
  89
  90     while(!feof(stdin)) {
  91         yyparse(regs, &base);
  92     }
  93     return 0;
  94 }
  95
  96 static void
  97 YYERROR_DECL()
  98 {
  99     fprintf(stderr, "%s\n", s);
 100 }
 101
 102 int
 103 YYLEX_DECL()
 104 {
 105         /* lexical analysis routine */
 106         /* returns LETTER for a lower case letter, yylval = 0 through 25 */
 107         /* return DIGIT for a digit, yylval = 0 through 9 */
 108         /* all other characters are returned immediately */
 109
 110     int c;
 111
 112     while( (c=getchar()) == ' ' )   { /* skip blanks */ }
 113
 114     /* c is now nonblank */
 115
 116     if( islower( c )) {
 117         *yylval = (c - 'a');
 118         return ( LETTER );
 119     }
 120     if( isdigit( c )) {
 121         *yylval = (c - '0') % (*base);
 122         return ( DIGIT );
 123     }
 124     return( c );
 125 }