aux/getflags: support named flags

When using aux/getflags, it produces unnecessarily obscure
names for the flags. This allows the caller of aux/getflags
to support arbitrary names.

sys/man/8/getflags

@@ -7,62 +7,98 @@ getflags, usage \- command-line parsing for shell scripts
 .B aux/usage
 .SH DESCRIPTION
 .I Getflags
-parses the options in its command-line arguments
+parses the flags in its command-line arguments
 according to the environment variable
 .BR $flagfmt .
-This variable should be a list of comma-separated options.
-Each option can be a single letter, indicating that it does
-not take arguments, or a letter followed by the space-separated
-names of its arguments.
+This variable should be a comma-separated list of flag specifiers.
+Each flag is a single letter, optionally followed by a
+colon and a name. It may be followed by a space-separated
+list of argument names.
+
+.PP
 .I Getflags 
 prints an 
 .IR rc (1)
-script on standard output which initializes the
-environment variable
-.BI $flag x
-for every option mentioned in 
-.BR $flagfmt .
-If the option is not present on the command-line, the script
-sets that option's flag variable to an empty list.
-Otherwise, the script sets that option's flag variable with
-a list containing the option's arguments or, 
-if the option takes no arguments,
-with the string
-.BR 1 .
-The script also sets the variable
+script to be evaluated by the calling program.
+For every flag specified in
+.BR $flagfmt ,
+the generated script sets a corresponding environment variable.
+If the flag specifier contains
+.BR :name ,
+the corresponding variable  is named
+.BR $name .
+Otherwise, it is named
+.BI $flag x.
+
+.PP
+After evaluating the script, the environment variables will
+be set as follows:
+If a flag is not present in the argument list, the environment
+variable will default to the empty list.
+If the flag is present and takes no arguments, the environment
+variable will be initialized with the string
+.BR '1' .
+If the flag takes arguments, the flag's variable will be initialized
+with a list of those argument values.
+The script then sets the variable
 .B $*
-to the list of arguments following the options.
-The final line in the script sets the
+to the list of remaining non-flag arguments.
+.PP
+The
 .B $status
-variable, to the empty string on success
-and to the string
-.B usage
+is variable to the empty string on success, or
+.B 'usage'
 when there is an error parsing the command line.
 .PP
 .I Usage
 prints a usage message to standard error.
-It creates the message using
-.BR $flagfmt ,
-as described above,
-.BR $args ,
-which should contain the string to be printed explaining
-non-option arguments,
-and
+The message is constructed using
 .BR $0 ,
-the program name
-(see
-.IR rc (1)).
+.BR $flagfmt ,
+and
+.BR $args .
+The program name is taken from
+.BR $0 ,
+as set by
+.IR rc (1)
+The list of flags is extracted from
+.BR $flagfmt .
+The description of positional argument list is taken from
+.BR  $args .
+
 .SH EXAMPLE
+.PP
+An example of the script generated:
+.IP
+.EX
+% flagfmt='e:example,x,a:arg with args'
+% aux/getflags -exa arg list positional stuff
+example=()
+flagx=()
+arg=()
+example=1
+flagx=1
+arg=(arg list)
+*=(positional stuff)
+status=''
+.EE
+.PP
 Parse the arguments for
 .IR leak (1):
 .IP
 .EX
-flagfmt='b,s,f binary,r res,x width'
+flagfmt='b:showbmp,s:acidfmt,f binary,r res,x width'
 args='name | pid list'
 if(! ifs=() eval `{aux/getflags $*} || ~ $#* 0){
 	aux/usage
 	exit usage
 }
+if(~ $#showbmp 0)
+	echo '-b flag not set'
+echo $showbmp	# named
+echo $acidfmt	# also named
+echo $flagf	# default name
+echo $flagr	# default name
 .EE
 .SH SOURCE
 .B /sys/src/cmd/aux/getflags.c

sys/src/cmd/aux/getflags.c

@@ -1,5 +1,6 @@
 #include <u.h>
 #include <libc.h>
+#include <ctype.h>
 
 void
 usage(void)
@@ -22,6 +23,21 @@ findarg(char *flags, Rune r)
 	return nil;	
 }
 
+char*
+argname(char *p)
+{
+	Rune r;
+	int n;
+
+	while(1){
+		n = chartorune(&r, p);
+		if(!isalpharune(r) && !isdigitrune(r))
+			break;
+		p += n;
+	}
+	return p;
+}
+
 int
 countargs(char *p)
 {
@@ -39,7 +55,7 @@ countargs(char *p)
 void
 main(int argc, char *argv[])
 {
-	char *flags, *p, buf[512];
+	char *flags, *p, *s, *e, buf[512];
 	int i, n;
 	Fmt fmt;
 	
@@ -55,18 +71,37 @@ main(int argc, char *argv[])
 	}
 
 	fmtfdinit(&fmt, 1, buf, sizeof buf);
-	for(p=flags; p!=(char*)1; p=strchr(p, ',')+1)
+	for(p=flags; p!=(char*)1 && *p != 0; p=strchr(p, ',')+1){
+		s = e = nil;
+		if(p[1] == ':'){
+			s = p + 2;
+			e = argname(s);
+		}
+		if(s != e)
+			fmtprint(&fmt, "%.*s=()\n", (int)(e - s), s);
+		else
 			fmtprint(&fmt, "flag%.1s=()\n", p);
+	}
 	ARGBEGIN{
 	default:
 		if((p = findarg(flags, ARGC())) == nil)
 			usage();
 		p += runelen(ARGC());
+		s = p + 1;
+		e = p + 1;
+		if(*p == ':' && (e = argname(s)) != s)
+			p = e;
 		if(*p == ',' || *p == 0){
+			if(s != e)
+				fmtprint(&fmt, "%.*s=1\n", (int)(e - s), s);
+			else
 				fmtprint(&fmt, "flag%C=1\n", ARGC());
 			break;
 		}
 		n = countargs(p);
+		if(s != e)
+			fmtprint(&fmt, "%.*s=(", (int)(e - s), s);
+		else
 			fmtprint(&fmt, "flag%C=(", ARGC());
 		for(i=0; i<n; i++)
 			fmtprint(&fmt, "%s%q", i ? " " : "", EARGF(usage()));

sys/src/cmd/aux/usage.c

@@ -31,6 +31,9 @@ main(void)
 		single = 0;
 		for(p=flags; *p; ){
 			p += chartorune(&r, p);
+			if(*p == ':')
+				while(*p != '\0' && *p != ',' && *p != ' ')
+					p++;
 			if(*p == ',' || *p == 0){
 				if(!single){
 					fmtprint(&fmt, " [-");