/* output each sequence of non-whitespace characters on
   a separate line preceded by a tab.  Think of this as
   a finite state machine with two states:
   inword and !inword 

   Mark A. Sheldon, Spring 2005
*/

#include <stdio.h>
#include <ctype.h>
#include <errno.h>

#define TRUE  1
#define FALSE 0
#define isdelimiter(c) !isalnum((c))

void parse_stream(FILE *in) {
  int c, inword = FALSE;
  
  while ((c = getc(in)) != EOF) {
    if (inword) {
      if (isdelimiter(c)) {
	inword = FALSE;
	putchar('\n');
      } else
	putchar(c);
    } else {
      if (!isdelimiter(c)) {
	inword = TRUE;
	printf("\t%c", c);
      }
    }
  }
}

int main(int argc, char *argv[]) {
  char *prog = argv[0];
  FILE *in;

  if (argc < 2) {
    fprintf(stderr, "Usage: %s -f\n       %s file1,...\n", argv[0], argv[0]);
    return 1;
  }

  if (strncmp(argv[1], "-f", 2) == 0) {
    if ( (strlen(argv[1]) != 2) || (argc != 2) ) {
      fprintf(stderr, "Usage: %s -f\n%s file1,...\n", argv[0]);
      return 1;
    }
    /* FILTER MODE */
    parse_stream(stdin);
    return 0;
  }

  /* FILE MODE */
  /* skip to first file name */
  argv++;   
  for (; argv != NULL; argv++) {

    in = fopen(*argv, "r");
    if (in == NULL) {
      perror(prog);
      return errno;
    }

    printf("%s\n", *argv);
    parse_stream(in);
  }
}