file completion

[Scott Schwartz <schwartz@groucho.cs.psu.edu>]

In honor of daylight savings time, here's a quick kludge to do csh style
file completion in rc.  Feeback solicited.

*** 1.1	1992/04/05 08:49:55
--- comp.c	1992/04/05 08:47:41
***************
*** 0 ****
--- 1,52 ----
+ #include "comp.h"
+ #include <sys/termios.h>
+ 
+ static int fdunread (int fd, char* buf, SIZE_T len);
+ 
+ /* read_with_completion -- if a line doesn't end with newline,
+      try and expand the last item to match things in the filesystem.
+      this function does it incorrectly, by looking for a whitespace
+      to delimit the final 'item'.  we really should parse the expression
+      and do completion on the last item computed in that way, and taking
+      error recovery into account.  Sanjeev is writing his dissertation on
+      an incremental parser --- ask him how to do it. */
+ 
+ extern int read_with_completion (int fd, char* buf, SIZE_T len) {
+   int r, n, i;
+   List* list;
+   char* meta;
+   char* p;
+ 
+   while (1) {
+     r = rc_read (fd, buf, len);
+     if (r <= 0 || buf[r-1] == '\n')
+       return r;
+     else {
+       buf[r] = '*';  /* XXX - caller has to make sure buf is big enough */
+       buf[r+1] = 0;
+       p = strrchr(buf, ' ');
+       if (p == 0) p = buf; else ++p;
+       n = r - (p-buf);
+       meta = ealloc(n+2);
+         clear(meta, n+2);
+         meta[n] = 1;
+         list = glob(word(p, meta));  /* XXX - what to return on failure? */
+         fprint (1, " # (%L)\n", list, " ");
+       efree(meta);
+       fdunread (fd, buf, r);
+     } 
+   }
+   /* NOTREACHED */
+ }
+ 
+ static int fdunread (int fd, char* buf, SIZE_T len) {
+   int r;
+   while (len--) {
+     r = ioctl (fd, TIOCSTI, buf++);
+     if (r < 0) {
+       uerror("ioctl/TIOCSTI");
+       return r;
+     } 
+   }
+   return 0;
+ }
*** 1.1	1992/04/04 20:14:03
--- input.c	1992/04/04 20:16:51
***************
*** 111,117 ****
--- 111,121 ----
  			} else
  #endif
  				{
+ #ifdef COMPLETION
+ 				long /*ssize_t*/ r = read_with_completion(istack->fd, inbuf + 2, BUFSIZE);
+ #else
  				long /*ssize_t*/ r = rc_read(istack->fd, inbuf + 2, BUFSIZE);
+ #endif
  				if (r < 0) {
  					if (errno == EINTR)
  						continue; /* Suppose it was interrupted by a signal */