1/* $NetBSD: calc2.y,v 1.1.1.3 2011/09/10 21:22:06 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%} 13 14%start list 15 16%token DIGIT LETTER 17 18%left '|' 19%left '&' 20%left '+' '-' 21%left '*' '/' '%' 22%left UMINUS /* supplies precedence for unary minus */ 23 24%% /* beginning of rules section */ 25 26list : /* empty */ 27 | list stat '\n' 28 | list error '\n' 29 { yyerrok ; } 30 ; 31 32stat : expr 33 { printf("%d\n",$1);} 34 | LETTER '=' expr 35 { regs[$1] = $3; } 36 ; 37 38expr : '(' expr ')' 39 { $$ = $2; } 40 | expr '+' expr 41 { $$ = $1 + $3; } 42 | expr '-' expr 43 { $$ = $1 - $3; } 44 | expr '*' expr 45 { $$ = $1 * $3; } 46 | expr '/' expr 47 { $$ = $1 / $3; } 48 | expr '%' expr 49 { $$ = $1 % $3; } 50 | expr '&' expr 51 { $$ = $1 & $3; } 52 | expr '|' expr 53 { $$ = $1 | $3; } 54 | '-' expr %prec UMINUS 55 { $$ = - $2; } 56 | LETTER 57 { $$ = regs[$1]; } 58 | number 59 ; 60 61number: DIGIT 62 { $$ = $1; (*base) = ($1==0) ? 8 : 10; } 63 | number DIGIT 64 { $$ = (*base) * $1 + $2; } 65 ; 66 67%% /* start of programs */ 68 69#ifdef YYBYACC 70extern int YYLEX_DECL(); 71static void YYERROR_DECL(); 72#endif 73 74int 75main (void) 76{ 77 int regs[26]; 78 int base = 10; 79 80 while(!feof(stdin)) { 81 yyparse(regs, &base); 82 } 83 return 0; 84} 85 86static void 87YYERROR_DECL() 88{ 89 fprintf(stderr, "%s\n", s); 90} 91 92int 93yylex(int *base) 94{ 95 /* lexical analysis routine */ 96 /* returns LETTER for a lower case letter, yylval = 0 through 25 */ 97 /* return DIGIT for a digit, yylval = 0 through 9 */ 98 /* all other characters are returned immediately */ 99 100 int c; 101 102 while( (c=getchar()) == ' ' ) { /* skip blanks */ } 103 104 /* c is now nonblank */ 105 106 if( islower( c )) { 107 yylval = c - 'a'; 108 return ( LETTER ); 109 } 110 if( isdigit( c )) { 111 yylval = (c - '0') % (*base); 112 return ( DIGIT ); 113 } 114 return( c ); 115} 116