1/* $NetBSD: calc_code_all.y,v 1.1.1.1 2021/02/20 20:30:07 christos Exp $ */ 2 3%code { /* CODE-DEFAULT2 */ } 4%code { /* CODE-DEFAULT */ } 5%code requires { /* CODE-REQUIRES */ } 6%code provides { /* CODE-PROVIDES */ } 7%code top { /* CODE-TOP */ } 8%code provides { /* CODE-PROVIDES2 */ } 9 10%{ 11# include <stdio.h> 12# include <ctype.h> 13 14int regs[26]; 15int base; 16 17extern int yylex(void); 18static void yyerror(const char *s); 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 77int 78main (void) 79{ 80 while(!feof(stdin)) { 81 yyparse(); 82 } 83 return 0; 84} 85 86static void 87yyerror(const char *s) 88{ 89 fprintf(stderr, "%s\n", s); 90} 91 92int 93yylex(void) 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'; 112 return ( DIGIT ); 113 } 114 return( c ); 115} 116