/* Parsing Logic */ #define WRD 1#define EOL 2 yyerror(char *msg) { fprintf(stderr,msg);return 0; } yyparse(){     register int c;    for(;;) { /* for each line */	switch( (c=yylex()) ) {	    case WRD : DefAction(yytext); /* define node */	       for(;;) { /* for each reference in line */		   switch( (c=yylex()) ) {		       case WRD: RefAction(yytext); /* reference node */		          continue;		       case EOL: break;		       default : yyerror("syntax error 2");continue;		   } break;	       } break;	    case 0: return 0;	    case EOL: continue;	    default: yyerror("syntax error 1");	}    }} #include "ctype.h" yylex(){    register int c;    while ( (c=getc(stdin)) != EOF ) {	if (c == '\n') return EOL;	else if (isspace(c)) {	    do { c = getc(stdin); } while (isspace(c));	    ungetc(c,stdin);continue;	} else {	    register char *p = yytext;	    do { *p++ = c; c = getc(stdin); } while (!isspace(c));	    ungetc(c,stdin); *p = 0;return WRD;	}    }    return 0;}