date and time created 83/04/26 01:18:13 by mckusick

[unix-history] / usr / src / usr.bin / learn / learn / getlesson.c

#ifndef lint
static char sccsid[] = "@(#)getlesson.c 4.1     (Berkeley)      %G%";
#endif not lint

#include "stdio.h"
#include "lrnref.h"

char *
getlesson()
{
       register char *p;
       char ans[80], line[200];
       int isnum, found, fd[2];
       FILE *fp;

       sprintf(ans, "%s/%s/L%s", direct, sname, level);
       if (access(ans, 04) == 0)               /* there is a file */
               return(level);
       isnum = 1;
       for (p=level; *p; p++)          /* accept:  (digit|dot)*anychar  */
               if (*p != '.' && (*p < '0' || *p > '9') && *(p+1) != '\0')
                       isnum = 0;
       if (isnum) {
               strcpy(line, level);
               p = level;
               while (*p != '.' && *p >= '0' && *p <= '9')
                       p++;
               *p = '\0';
               strcat(level, ".1a");
               sprintf(ans, "%s/%s/L%s", direct, sname, level);
               if (access(ans, 04) == 0) {     /* there is a file */
                       printf("There is no lesson %s; trying lesson %s instead.\n\n", line, level);
                       return(level);
               }
               printf("There is no lesson %s.\n", line);
               return(0);
       }
       /* fgrep through lessons for one containing the string in 'level' */
       pipe(fd);
       if (fork() == 0) {
               close(fd[0]);
               dup2(fd[1], 1);
               sprintf(ans,"cd %s/%s ; fgrep '%s' L?.* L??.* L???.*", direct, sname, level);
               execl("/bin/csh", "csh", "-cf", ans, 0);
               perror("/bin/csh");
               fprintf(stderr, "Getlesson:  can't do %s\n", ans);
       }
       close(fd[1]);
       fp = fdopen(fd[0], "r");
       found = 0;
       while (fgets(line, 200, fp) != NULL) {
               for (p=line; *p != ':'; p++) ;
               p++;
               if (*p == '#')
                       continue;
               else {
                       found = 1;
                       break;
               }
       }
       /*fclose(fp);*/
       if (found) {
               *--p = '\0';
               strcpy(level, &line[1]);
               sprintf(ans, "%s/%s/L%s", direct, sname, level);
               if (access(ans, 04) == 0) {     /* there is a file */
                       printf("Trying lesson %s.\n\n", level);
                       return(level);
               }
       }
       printf("There is no lesson containing \"%s\".\n", level);
       return(0);
}