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- %{
- #define YYSTYPE double
- #include <stdio.h>
- // yylex() is generated by flex
- int yylex(void);
- // we have to define yyerror()
- int yyerror (char const *);
- %}
- %token NUMBER
- %left '+' '-'
- %left '*' '/'
- %right '('
- %%
- stmtlist: statement '\n' stmtlist {
- printf("done with statement equal to [%g]\n", $1);
- } | // EMPTY RULE i.e. stmtlist -> nil
- { printf("DONE\n") ;};
- statement: expression { printf("VALUE=%g\n",$1); };
- expression: expression '+' expression { $$ = $1 + $3; } |
- expression '-' expression { $$ = $1 - $3; } |
- expression '*' expression { $$ = $1 * $3; } |
- expression '/' expression {
- if($3 !=0) { $$ = $1 / $3; } else
- { printf("div by zero\n"); $$=0;} } |
- '(' expression ')' { $$ = $2; } |
- NUMBER { $$ = $1; } ;
- %%
|
