Re: [9front] Patch to fix test(1) expression parsing

[Alex Musolino <alex@musolino.id.au>]

> Yeah, I did this in an updated patch I sent in a subsequent email.

It turns out that the second patch is rubbish too.  This one should be
better.  I've further amended the man page to also drop the
description of an unimplemented feature.  I'm using a test suite [1]
derived from something joe9 posted in #cat-v which, in turn, was based
on something from OpenBSD.

[1] http://musolino.id.au/up/2020/08/03/test.testsuite.rc

diff -r aa3d84fc81f6 sys/man/1/test
--- a/sys/man/1/test	Sun Aug 02 18:30:01 2020 +0930
+++ b/sys/man/1/test	Mon Aug 03 23:11:04 2020 +0930
@@ -100,11 +100,6 @@
 .BR -le
 may be used in place of
 .BR -eq .
-The (nonstandard) construct
-.BI -l " string\f1,
-meaning the length of
-.IR string ,
-may be used in place of an integer.
 .TP
 .IB a " -nt " b
 True if file
@@ -209,10 +204,3 @@
 .B /sys/src/cmd/test.c
 .SH "SEE ALSO"
 .IR rc (1) 
-.SH BUGS
-Won't complain about extraneous arguments
-since there may be arguments left unprocessed by
-short-circuit evaluation of
-.B -a
-or
-.BR -o .
diff -r aa3d84fc81f6 sys/src/cmd/test.c
--- a/sys/src/cmd/test.c	Sun Aug 02 18:30:01 2020 +0930
+++ b/sys/src/cmd/test.c	Mon Aug 03 23:11:04 2020 +0930
@@ -30,7 +30,7 @@
 int	isnewerthan(char *, char *);
 int	hasmode(char *, ulong);
 int	tio(char *, int);
-int	e(void), e1(void), e2(void), e3(void);
+int	e(int), e1(int), e2(int), e3(int);
 char	*nxtarg(int);
 
 void
@@ -47,12 +47,8 @@
 	argv[ac] = 0;
 	if (ac<=1)
 		exits("usage");
-	r = e();
-	/*
-	 * nice idea but short-circuit -o and -a operators may have
-	 * not consumed their right-hand sides.
-	 */
-	if(0 && (c = nxtarg(1)) != nil)
+	r = e(1);
+	if((c = nxtarg(1)) != nil)
 		synbad("unexpected operator/operand: ", c);
 	exits(r?0:"false");
 }
@@ -81,78 +77,128 @@
 }
 
 int
-e(void)
+e(int eval)
 {
+	char *op;
 	int p1;
 
-	p1 = e1();
-	if (EQ(nxtarg(1), "-o"))
-		return(p1 || e());
-	ap--;
-	return(p1);
+	p1 = e1(eval);
+	for(;;){
+		op = nxtarg(1);
+		if(op == nil)
+			break;
+		if(!EQ(op, "-o")){
+			ap--;
+			return p1;
+		}
+		if(!p1 && eval)
+			p1 |= e1(1);
+		else
+			e1(0);
+	}
+	return p1;
 }
 
 int
-e1(void)
+e1(int eval)
 {
+	char *op;
 	int p1;
 
-	p1 = e2();
-	if (EQ(nxtarg(1), "-a"))
-		return (p1 && e1());
-	ap--;
-	return(p1);
+	p1 = e2(eval);
+	for(;;){
+		op = nxtarg(1);
+		if(op == nil)
+			break;
+		if(!EQ(op, "-a")){
+			ap--;
+			return p1;
+		}
+		if(p1 && eval)
+			p1 &= e2(1);
+		else
+			e2(0);
+	}
+	return p1;
 }
 
 int
-e2(void)
+e2(int eval)
 {
-	if (EQ(nxtarg(0), "!"))
-		return(!e2());
+	char *op;
+	int p1;
+
+	p1 = 0;
+	for(;;){
+		op = nxtarg(1);
+		if(op == nil)
+			return p1 ^ 1;
+		if(!EQ(op, "!"))
+			break;
+		p1 ^= 1;
+	}
 	ap--;
-	return(e3());
+	return(p1^e3(eval));
 }
 
 int
-e3(void)
+e3(int eval)
 {
 	int p1, int1, int2;
-	char *a, *p2;
+	char *a, *b, *p2;
 
 	a = nxtarg(0);
 	if(EQ(a, "(")) {
-		p1 = e();
+		p1 = e(eval);
 		if(!EQ(nxtarg(0), ")"))
 			synbad(") expected","");
 		return(p1);
 	}
 
-	if(EQ(a, "-A"))
-		return(hasmode(nxtarg(0), DMAPPEND));
+	if(EQ(a, "-A")){
+		b = nxtarg(0);
+		return(eval && hasmode(b, DMAPPEND));
+	}
 
-	if(EQ(a, "-L"))
-		return(hasmode(nxtarg(0), DMEXCL));
+	if(EQ(a, "-L")){
+		b = nxtarg(0);
+		return(eval && hasmode(b, DMEXCL));
+	}
 
-	if(EQ(a, "-T"))
-		return(hasmode(nxtarg(0), DMTMP));
+	if(EQ(a, "-T")){
+		b = nxtarg(0);
+		return(eval && hasmode(b, DMTMP));
+	}
 
-	if(EQ(a, "-f"))
-		return(isreg(nxtarg(0)));
+	if(EQ(a, "-f")){
+		b = nxtarg(0);
+		return(eval && isreg(b));
+	}
 
-	if(EQ(a, "-d"))
-		return(isdir(nxtarg(0)));
+	if(EQ(a, "-d")){
+		b = nxtarg(0);
+		return(eval && isdir(b));
+	}
 
-	if(EQ(a, "-r"))
-		return(tio(nxtarg(0), AREAD));
+	if(EQ(a, "-r")){
+		b = nxtarg(0);
+		return(eval && tio(b, AREAD));
+	}
 
-	if(EQ(a, "-w"))
-		return(tio(nxtarg(0), AWRITE));
+	if(EQ(a, "-w")){
+		b = nxtarg(0);
+		return(eval && tio(b, AWRITE));
+	}
 
-	if(EQ(a, "-x"))
-		return(tio(nxtarg(0), AEXEC));
+	if(EQ(a, "-x")){
+		b = nxtarg(0);
+		return(eval && tio(b, AEXEC));
+	}
 
-	if(EQ(a, "-e"))
-		return(tio(nxtarg(0), AEXIST));
+	if(EQ(a, "-e")){
+		b = nxtarg(0);
+		return(eval && tio(b, AEXIST));
+	}
 
 	if(EQ(a, "-c"))
 		return(0);
@@ -166,14 +212,16 @@
 	if(EQ(a, "-g"))
 		return(0);
 
-	if(EQ(a, "-s"))
-		return(fsizep(nxtarg(0)));
+	if(EQ(a, "-s")){
+		b = nxtarg(0);
+		return(eval && fsizep(b));
+	}
 
 	if(EQ(a, "-t"))
 		if(ap>=ac)
-			return(isatty(1));
+			return(eval && isatty(1));
 		else if(nxtintarg(&int1))
-			return(isatty(int1));
+			return(eval && isatty(int1));
 		else
 			synbad("not a valid file descriptor number ", "");
 
@@ -191,35 +239,40 @@
 	if(EQ(p2, "!="))
 		return(!EQ(nxtarg(0), a));
 
-	if(EQ(p2, "-older"))
-		return(isolder(nxtarg(0), a));
-
-	if(EQ(p2, "-ot"))
-		return(isolderthan(nxtarg(0), a));
-
-	if(EQ(p2, "-nt"))
-		return(isnewerthan(nxtarg(0), a));
-
-	if(!isint(a, &int1))
-		synbad("unexpected operator/operand: ", p2);
-
-	if(nxtintarg(&int2)){
-		if(EQ(p2, "-eq"))
-			return(int1==int2);
-		if(EQ(p2, "-ne"))
-			return(int1!=int2);
-		if(EQ(p2, "-gt"))
-			return(int1>int2);
-		if(EQ(p2, "-lt"))
-			return(int1<int2);
-		if(EQ(p2, "-ge"))
-			return(int1>=int2);
-		if(EQ(p2, "-le"))
-			return(int1<=int2);
+	if(EQ(p2, "-older")){
+		b = nxtarg(0);
+		return(eval && isolder(b, a));
 	}
 
-	synbad("unknown operator ",p2);
-	return 0;		/* to shut ken up */
+	if(EQ(p2, "-ot")){
+		b = nxtarg(0);
+		return(eval && isolderthan(b, a));
+	}
+
+	if(EQ(p2, "-nt")){
+		b = nxtarg(0);
+		return(eval && isnewerthan(b, a));
+	}
+
+	if(isint(a, &int1)){
+		if(nxtintarg(&int2)){
+			if(EQ(p2, "-eq"))
+				return(int1==int2);
+			if(EQ(p2, "-ne"))
+				return(int1!=int2);
+			if(EQ(p2, "-gt"))
+				return(int1>int2);
+			if(EQ(p2, "-lt"))
+				return(int1<int2);
+			if(EQ(p2, "-ge"))
+				return(int1>=int2);
+			if(EQ(p2, "-le"))
+				return(int1<=int2);
+			ap--;
+		}
+	}
+	ap--;
+	return !EQ(a, "");
 }
 
 int