Re: Determing type for command name

[Peter Stephenson <pws@xxxxxx>]

Nik Gervae wrote:
> I find myself needing to selectively undefine aliases or functions
> in different situations. The whence -v command, which gives a verbose,
> English description, will suffice, but doesn't seem robust enough
> to me. More specifically, there's no guarantee that the descriptions
> won't change without warning between releases. Can we have a new
> flag on whence that will cause it to print a single, well-defined,
> and documented word for each of the possibilities?

I think that's an excellent idea.  whence -w (or type -w, since one
would intuitively expect that to work) now does just that.  On the
other hand, you can probably solve the problem I presume you have by
testing the return statuses of `alias foo >&/dev/null' and `functions foo
>&/dev/null'.

*** Doc/Zsh/builtins.yo.word	Thu Jun 12 14:36:06 1997
--- Doc/Zsh/builtins.yo	Wed Sep 16 11:46:56 1998
***************
*** 848,854 ****
  terminal is frozen or not.
  )
  findex(type)
! item(tt(type) [ tt(-fpams) ] var(name) ...)(
  Equivalent to tt(whence -v).
  )
  findex(typeset)
--- 848,854 ----
  terminal is frozen or not.
  )
  findex(type)
! item(tt(type) [ tt(-wfpams) ] var(name) ...)(
  Equivalent to tt(whence -v).
  )
  findex(typeset)
***************
*** 1026,1032 ****
  The exit status from this command is that of the job waited for.
  )
  findex(whence)
! item(tt(whence) [ tt(-vcfpams) ] var(name) ...)(
  For each name, indicate how it would be interpreted if used as a
  command name.
  
--- 1026,1032 ----
  The exit status from this command is that of the job waited for.
  )
  findex(whence)
! item(tt(whence) [ tt(-vcwfpams) ] var(name) ...)(
  For each name, indicate how it would be interpreted if used as a
  command name.
  
***************
*** 1037,1042 ****
--- 1037,1051 ----
  item(tt(-c))(
  Print the results in a bf(csh)-like format.
  This takes precedence over tt(-v).
+ )
+ item(tt(-w))(
+ For each var(name), print `var(name)tt(:) var(word)' where var(word)
+ is one of tt(alias), tt(builtin), tt(command), tt(function),
+ tt(hashed), tt(reserved) or tt(none), according as var(name)
+ corresponds to an alias, a built-in command, an external command, a
+ shell function, a command defined with the tt(hash) builtin, a
+ reserved word, or is not recognised.  This takes precedence over
+ tt(-v) and tt(-c).
  )
  item(tt(-f))(
  Causes the contents of a shell function to be
*** Src/builtin.c.word	Wed Aug 19 15:37:27 1998
--- Src/builtin.c	Wed Sep 16 11:33:20 1998
***************
*** 106,112 ****
      BUILTIN("times", BINF_PSPECIAL, bin_times, 0, 0, 0, NULL, NULL),
      BUILTIN("trap", BINF_PSPECIAL, bin_trap, 0, -1, 0, NULL, NULL),
      BUILTIN("true", 0, bin_true, 0, -1, 0, NULL, NULL),
!     BUILTIN("type", 0, bin_whence, 0, -1, 0, "ampfs", "v"),
      BUILTIN("typeset", BINF_TYPEOPTS | BINF_MAGICEQUALS | BINF_PSPECIAL, bin_typeset, 0, -1, 0, "LRUZfilrtuxm", NULL),
      BUILTIN("umask", 0, bin_umask, 0, 1, 0, "S", NULL),
      BUILTIN("unalias", 0, bin_unhash, 1, -1, 0, "m", "a"),
--- 106,112 ----
      BUILTIN("times", BINF_PSPECIAL, bin_times, 0, 0, 0, NULL, NULL),
      BUILTIN("trap", BINF_PSPECIAL, bin_trap, 0, -1, 0, NULL, NULL),
      BUILTIN("true", 0, bin_true, 0, -1, 0, NULL, NULL),
!     BUILTIN("type", 0, bin_whence, 0, -1, 0, "ampfsw", "v"),
      BUILTIN("typeset", BINF_TYPEOPTS | BINF_MAGICEQUALS | BINF_PSPECIAL, bin_typeset, 0, -1, 0, "LRUZfilrtuxm", NULL),
      BUILTIN("umask", 0, bin_umask, 0, 1, 0, "S", NULL),
      BUILTIN("unalias", 0, bin_unhash, 1, -1, 0, "m", "a"),
***************
*** 115,121 ****
      BUILTIN("unset", BINF_PSPECIAL, bin_unset, 1, -1, 0, "fm", NULL),
      BUILTIN("unsetopt", 0, bin_setopt, 0, -1, BIN_UNSETOPT, NULL, NULL),
      BUILTIN("wait", 0, bin_fg, 0, -1, BIN_WAIT, NULL, NULL),
!     BUILTIN("whence", 0, bin_whence, 0, -1, 0, "acmpvfs", NULL),
      BUILTIN("where", 0, bin_whence, 0, -1, 0, "pms", "ca"),
      BUILTIN("which", 0, bin_whence, 0, -1, 0, "amps", "c"),
  
--- 115,121 ----
      BUILTIN("unset", BINF_PSPECIAL, bin_unset, 1, -1, 0, "fm", NULL),
      BUILTIN("unsetopt", 0, bin_setopt, 0, -1, BIN_UNSETOPT, NULL, NULL),
      BUILTIN("wait", 0, bin_fg, 0, -1, BIN_WAIT, NULL, NULL),
!     BUILTIN("whence", 0, bin_whence, 0, -1, 0, "acmpvfsw", NULL),
      BUILTIN("where", 0, bin_whence, 0, -1, 0, "pms", "ca"),
      BUILTIN("which", 0, bin_whence, 0, -1, 0, "amps", "c"),
  
***************
*** 162,167 ****
--- 162,172 ----
  {
      Builtin bn = (Builtin) hn;
  
+     if (printflags & PRINT_WHENCE_WORD) {
+ 	printf("%s: builtin\n", bn->nam);
+ 	return;
+     }
+ 
      if (printflags & PRINT_WHENCE_CSH) {
  	printf("%s: shell built-in command\n", bn->nam);
  	return;
***************
*** 1807,1813 ****
      Comp com;
      int returnval = 0;
      int printflags = 0;
!     int csh, all, v;
      int informed;
      char *cnam;
  
--- 1812,1818 ----
      Comp com;
      int returnval = 0;
      int printflags = 0;
!     int csh, all, v, wd;
      int informed;
      char *cnam;
  
***************
*** 1815,1822 ****
      csh = ops['c'];
      v   = ops['v'];
      all = ops['a'];
  
!     if (ops['c'])
  	printflags |= PRINT_WHENCE_CSH;
      else if (ops['v'])
  	printflags |= PRINT_WHENCE_VERBOSE;
--- 1820,1830 ----
      csh = ops['c'];
      v   = ops['v'];
      all = ops['a'];
+     wd  = ops['w'];
  
!     if (ops['w'])
! 	printflags |= PRINT_WHENCE_WORD;
!     else if (ops['c'])
  	printflags |= PRINT_WHENCE_CSH;
      else if (ops['v'])
  	printflags |= PRINT_WHENCE_VERBOSE;
***************
*** 1919,1951 ****
  		    continue;
  		strcpy(z, *argv);
  		if (iscom(buf)) {
! 		    if (v && !csh)
! 			zputs(*argv, stdout), fputs(" is ", stdout);
! 		    zputs(buf, stdout);
! 		    if (ops['s'])
! 			print_if_link(buf);
! 		    fputc('\n', stdout);
  		    informed = 1;
  		}
  	    }
! 	    if (!informed && (v || csh)) {
  		zputs(*argv, stdout);
! 		puts(" not found");
  		returnval = 1;
  	    }
  	} else if ((cnam = findcmd(*argv))) {
  	    /* Found external command. */
! 	    if (v && !csh)
! 		zputs(*argv, stdout), fputs(" is ", stdout);
! 	    zputs(cnam, stdout);
! 	    if (ops['s'])
! 		print_if_link(cnam);
! 	    fputc('\n', stdout);
  	    zsfree(cnam);
  	} else {
  	    /* Not found at all. */
! 	    if (v || csh)
! 		zputs(*argv, stdout), puts(" not found");
  	    returnval = 1;
  	}
      }
--- 1927,1967 ----
  		    continue;
  		strcpy(z, *argv);
  		if (iscom(buf)) {
! 		    if (wd) {
! 			printf("%s: command\n", *argv);
! 		    } else {
! 			if (v && !csh)
! 			    zputs(*argv, stdout), fputs(" is ", stdout);
! 			zputs(buf, stdout);
! 			if (ops['s'])
! 			    print_if_link(buf);
! 			fputc('\n', stdout);
! 		    }
  		    informed = 1;
  		}
  	    }
! 	    if (!informed && (wd || v || csh)) {
  		zputs(*argv, stdout);
! 		puts(wd ? ": none" : " not found");
  		returnval = 1;
  	    }
  	} else if ((cnam = findcmd(*argv))) {
  	    /* Found external command. */
! 	    if (wd) {
! 		printf("%s: command\n", *argv);
! 	    } else {
! 		if (v && !csh)
! 		    zputs(*argv, stdout), fputs(" is ", stdout);
! 		zputs(cnam, stdout);
! 		if (ops['s'])
! 		    print_if_link(cnam);
! 		fputc('\n', stdout);
! 	    }
  	    zsfree(cnam);
  	} else {
  	    /* Not found at all. */
! 	    if (v || csh || wd)
! 		zputs(*argv, stdout), puts(wd ? ": none" : " not found");
  	    returnval = 1;
  	}
      }
*** Src/hashtable.c.word	Wed Apr 29 23:42:48 1998
--- Src/hashtable.c	Wed Sep 16 11:21:00 1998
***************
*** 655,660 ****
--- 655,666 ----
  {
      Cmdnam cn = (Cmdnam) hn;
  
+     if (printflags & PRINT_WHENCE_WORD) {
+ 	printf("%s: %s\n", cn->nam, (cn->flags & HASHED) ? 
+ 	       "hashed" : "command");
+ 	return;
+     }
+ 
      if ((printflags & PRINT_WHENCE_CSH) || (printflags & PRINT_WHENCE_SIMPLE)) {
  	if (cn->flags & HASHED) {
  	    zputs(cn->u.cmd, stdout);
***************
*** 813,822 ****
  	return;
      }
   
!     if ((printflags & PRINT_WHENCE_VERBOSE) &&
  	!(printflags & PRINT_WHENCE_FUNCDEF)) {
  	nicezputs(f->nam, stdout);
! 	printf(" is a shell function\n");
  	return;
      }
   
--- 819,829 ----
  	return;
      }
   
!     if ((printflags & (PRINT_WHENCE_VERBOSE|PRINT_WHENCE_WORD)) &&
  	!(printflags & PRINT_WHENCE_FUNCDEF)) {
  	nicezputs(f->nam, stdout);
! 	printf((printflags & PRINT_WHENCE_WORD) ? ": function\n" :
! 	       " is a shell function\n");
  	return;
      }
   
***************
*** 911,916 ****
--- 918,928 ----
  {
      Reswd rw = (Reswd) hn;
  
+     if (printflags & PRINT_WHENCE_WORD) {
+ 	printf("%s: reserved\n", rw->nam);
+ 	return;
+     }
+ 
      if (printflags & PRINT_WHENCE_CSH) {
  	printf("%s: shell reserved word\n", rw->nam);
  	return;
***************
*** 996,1001 ****
--- 1008,1018 ----
      if (printflags & PRINT_NAMEONLY) {
  	zputs(a->nam, stdout);
  	putchar('\n');
+ 	return;
+     }
+ 
+     if (printflags & PRINT_WHENCE_WORD) {
+ 	printf("%s: alias\n", a->nam);
  	return;
      }
  
*** Src/zsh.h.word	Thu Jul  9 12:04:44 1998
--- Src/zsh.h	Wed Sep 16 11:01:53 1998
***************
*** 892,897 ****
--- 892,898 ----
  #define PRINT_WHENCE_VERBOSE	(1<<4)
  #define PRINT_WHENCE_SIMPLE	(1<<5)
  #define PRINT_WHENCE_FUNCDEF	(1<<6)
+ #define PRINT_WHENCE_WORD	(1<<7)
  
  /***********************************/
  /* Definitions for history control */

-- 
Peter Stephenson <pws@xxxxxx>       Tel: +39 50 844536
WWW:  http://www.ifh.de/~pws/
Gruppo Teorico, Dipartimento di Fisica
Piazza Torricelli 2, 56100 Pisa, Italy