pgas mentioned ksh93 does [[ $foo ]] (ipv forced [[ -n $foo ]])

and it actually REDUCES code size to allow it as well; mention
in the manpage that it’s merely unportable (and of course exe-
cution time differs); sync clog

check.t

@@ -1,4 +1,4 @@
-# $MirOS: src/bin/mksh/check.t,v 1.278 2009/05/20 10:10:00 tg Exp $
+# $MirOS: src/bin/mksh/check.t,v 1.279 2009/05/21 14:28:32 tg Exp $
 # $OpenBSD: bksl-nl.t,v 1.2 2001/01/28 23:04:56 niklas Exp $
 # $OpenBSD: history.t,v 1.5 2001/01/28 23:04:56 niklas Exp $
 # $OpenBSD: read.t,v 1.3 2003/03/10 03:48:16 david Exp $
@@ -25,7 +25,7 @@
 # http://www.research.att.com/~gsf/public/ifs.sh
 
 expected-stdout:
-	@(#)MIRBSD KSH R38 2009/05/19
+	@(#)MIRBSD KSH R38 2009/05/21
 description:
 	Check version of shell.
 stdin:
@@ -5632,3 +5632,93 @@ stdin:
 expected-stdout:
 	yes
 ---
+name: test-stnze-1
+description:
+	Check that the short form [ $x ] works
+stdin:
+	i=0
+	[ -n $x ]
+	rv=$?; echo $((++i)) $rv
+	[ $x ]
+	rv=$?; echo $((++i)) $rv
+	[ -n "$x" ]
+	rv=$?; echo $((++i)) $rv
+	[ "$x" ]
+	rv=$?; echo $((++i)) $rv
+	x=0
+	[ -n $x ]
+	rv=$?; echo $((++i)) $rv
+	[ $x ]
+	rv=$?; echo $((++i)) $rv
+	[ -n "$x" ]
+	rv=$?; echo $((++i)) $rv
+	[ "$x" ]
+	rv=$?; echo $((++i)) $rv
+	x='1 -a 1 = 2'
+	[ -n $x ]
+	rv=$?; echo $((++i)) $rv
+	[ $x ]
+	rv=$?; echo $((++i)) $rv
+	[ -n "$x" ]
+	rv=$?; echo $((++i)) $rv
+	[ "$x" ]
+	rv=$?; echo $((++i)) $rv
+expected-stdout:
+	1 0
+	2 1
+	3 1
+	4 1
+	5 0
+	6 0
+	7 0
+	8 0
+	9 1
+	10 1
+	11 0
+	12 0
+---
+name: test-stnze-2
+description:
+	Check that the short form [[ $x ]] works (ksh93 extension)
+stdin:
+	i=0
+	[[ -n $x ]]
+	rv=$?; echo $((++i)) $rv
+	[[ $x ]]
+	rv=$?; echo $((++i)) $rv
+	[[ -n "$x" ]]
+	rv=$?; echo $((++i)) $rv
+	[[ "$x" ]]
+	rv=$?; echo $((++i)) $rv
+	x=0
+	[[ -n $x ]]
+	rv=$?; echo $((++i)) $rv
+	[[ $x ]]
+	rv=$?; echo $((++i)) $rv
+	[[ -n "$x" ]]
+	rv=$?; echo $((++i)) $rv
+	[[ "$x" ]]
+	rv=$?; echo $((++i)) $rv
+	x='1 -a 1 = 2'
+	[[ -n $x ]]
+	rv=$?; echo $((++i)) $rv
+	[[ $x ]]
+	rv=$?; echo $((++i)) $rv
+	[[ -n "$x" ]]
+	rv=$?; echo $((++i)) $rv
+	[[ "$x" ]]
+	rv=$?; echo $((++i)) $rv
+expected-stdout:
+	1 1
+	2 1
+	3 1
+	4 1
+	5 0
+	6 0
+	7 0
+	8 0
+	9 0
+	10 0
+	11 0
+	12 0
+---

funcs.c

@@ -25,7 +25,7 @@
 
 #include "sh.h"
 
-__RCSID("$MirOS: src/bin/mksh/funcs.c,v 1.108 2009/05/20 10:10:01 tg Exp $");
+__RCSID("$MirOS: src/bin/mksh/funcs.c,v 1.109 2009/05/21 14:28:33 tg Exp $");
 
 /* A leading = means assignments before command are kept;
  * a leading * means a POSIX special builtin;
@@ -2825,10 +2825,6 @@ test_primary(Test_env *te, bool do_eval)
 
 		return (*te->eval)(te, op, opnd1, opnd2, do_eval);
 	}
-	if (te->flags & TEF_DBRACKET) {
-		(*te->error)(te, -1, "missing expression operator");
-		return 0;
-	}
 	return (*te->eval)(te, TO_STNZE, opnd1, NULL, do_eval);
 }
 

mksh.1

@@ -1,4 +1,4 @@
-.\" $MirOS: src/bin/mksh/mksh.1,v 1.166 2009/05/16 18:40:08 tg Exp $
+.\" $MirOS: src/bin/mksh/mksh.1,v 1.167 2009/05/21 14:28:34 tg Exp $
 .\" $OpenBSD: ksh.1,v 1.128 2009/03/06 12:28:36 jmc Exp $
 .\"-
 .\" Copyright © 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009
@@ -48,7 +48,7 @@
 .el .xD \\$1 \\$2 \\$3 \\$4 \\$5 \\$6 \\$7 \\$8
 ..
 .\"-
-.Dd $Mdocdate: May 16 2009 $
+.Dd $Mdocdate: May 21 2009 $
 .Dt MKSH 1
 .Os MirBSD
 .Sh NAME
@@ -794,8 +794,8 @@ succeeds).
 .It
 The single argument form of
 .Ic test ,
-which tests if the argument has a non-zero length, is not valid; explicit
+which tests if the argument has a non-zero length, is not portable,
-operators must always be used, e.g. instead of
+e.g. instead of
 .No \&[ Ar str No \&]
 use
 .No \&[[ \-n Ar str No \&]] .

sh.h

@@ -122,9 +122,9 @@
 #define __SCCSID(x)	__IDSTRING(sccsid,x)
 
 #ifdef EXTERN
-__RCSID("$MirOS: src/bin/mksh/sh.h,v 1.301 2009/05/20 10:10:02 tg Exp $");
+__RCSID("$MirOS: src/bin/mksh/sh.h,v 1.302 2009/05/21 14:28:35 tg Exp $");
 #endif
-#define MKSH_VERSION "R38 2009/05/19"
+#define MKSH_VERSION "R38 2009/05/21"
 
 #ifndef MKSH_INCLUDES_ONLY