1/* $NetBSD: calc2.y,v 1.1.1.7 2016/01/09 21:59:45 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) 16int YYLEX_DECL(); 17static 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 34list : /* empty */ 35 | list stat '\n' 36 | list error '\n' 37 { yyerrok ; } 38 ; 39 40stat : expr 41 { printf("%d\n",$1);} 42 | LETTER '=' expr 43 { regs[$1] = $3; } 44 ; 45 46expr : '(' 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 69number: 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 78extern int YYLEX_DECL(); 79#endif 80 81int 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 95static void 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 103int 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