/* re2c lesson 001_upn_calculator, calc_002, (c) M. Boerger 2006 - 2007 */ /*!ignore:re2c - making use of YYFILL . Here we modified the scanner to not require strlen() on the call. Instead we compute limit on the fly. That is whenever more input is needed we search for the terminating \0 in the next n chars the scanner needs. . If there is not enough input we quit the scanner. . Note that in lesson_001 YYLIMIT was a character pointer computed only once. Here is of course also of type YYCTYPE but a variable that gets reevaluated by YYFILL(). . To make the code smaller we take advantage of the fact that our loop has no break so far. This allows us to use break here and have the code that is used for YYFILL() not contain the printf in every occurence. That way the generated code gets smaller. */ #include #include #include int fill(char *p, int n, char **l) { while (*++p && n--) ; * l = p; return n <= 0; } int scan(char *s) { char *p = s; char *l = s; char *q = 0; #define YYCTYPE char #define YYCURSOR p #define YYLIMIT l #define YYMARKER q #define YYFILL(n) { if (!fill(p, n, &l)) break; } for(;;) { /*!re2c re2c:indent:top = 2; "0"[0-9]+ { printf("Oct\n"); continue; } [1-9][0-9]* { printf("Num\n"); continue; } "0" { printf("Num\n"); continue; } "+" { printf("+\n"); continue; } "-" { printf("+\n"); continue; } "\000" { printf("EOF\n"); return 0; } [^] { printf("ERR\n"); return 1; } */ } printf("OOD\n"); return 2; } int main(int argc, char **argv) { if (argc > 1) { return scan(argv[1]); } else { fprintf(stderr, "%s \n", argv[0]); return 0; } }