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 main(void)82main (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 YYERROR_DECL()96YYERROR_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 YYLEX_DECL()104YYLEX_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 } 127