1 /* $NetBSD: calc3.y,v 1.1.1.1 2010/12/23 23:36:30 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 %} 15 16 %start list 17 18 %token DIGIT LETTER 19 20 %left '|' 21 %left '&' 22 %left '+' '-' 23 %left '*' '/' '%' 24 %left UMINUS /* supplies precedence for unary minus */ 25 26 %% /* beginning of rules section */ 27 28 list : /* empty */ 29 | list stat '\n' 30 | list error '\n' 31 { yyerrok ; } 32 ; 33 34 stat : expr 35 { printf("%d\n",$1);} 36 | LETTER '=' expr 37 { regs[$1] = $3; } 38 ; 39 40 expr : '(' expr ')' 41 { $$ = $2; } 42 | expr '+' expr 43 { $$ = $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 { $$ = $1 & $3; } 54 | expr '|' expr 55 { $$ = $1 | $3; } 56 | '-' expr %prec UMINUS 57 { $$ = - $2; } 58 | LETTER 59 { $$ = regs[$1]; } 60 | number 61 ; 62 63 number: DIGIT 64 { $$ = $1; (*base) = ($1==0) ? 8 : 10; } 65 | number DIGIT 66 { $$ = (*base) * $1 + $2; } 67 ; 68 69 %% /* start of programs */ 70 71 int 72 main (void) 73 { 74 int regs[26]; 75 int base = 10; 76 77 while(!feof(stdin)) { 78 yyparse(regs, &base); 79 } 80 return 0; 81 } 82 83 static void 84 YYERROR_DECL() 85 { 86 fprintf(stderr, "%s\n", s); 87 } 88 89 int 90 YYLEX_DECL() 91 { 92 /* lexical analysis routine */ 93 /* returns LETTER for a lower case letter, yylval = 0 through 25 */ 94 /* return DIGIT for a digit, yylval = 0 through 9 */ 95 /* all other characters are returned immediately */ 96 97 int c; 98 99 while( (c=getchar()) == ' ' ) { /* skip blanks */ } 100 101 /* c is now nonblank */ 102 103 if( islower( c )) { 104 *yylval = (c - 'a'); 105 return ( LETTER ); 106 } 107 if( isdigit( c )) { 108 *yylval = (c - '0') % (*base); 109 return ( DIGIT ); 110 } 111 return( c ); 112 } 113