ref: 380adf8b485ce93aa42ad0d414718c3ad4918176
parent: 8ae77554dda425997faa8c7562613cc06586a209
author: Ori Bernstein <ori@eigenstate.org>
date: Sat Apr 18 11:38:38 EDT 2020
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.
--- a/sys/man/8/getflags
+++ b/sys/man/8/getflags
@@ -7,62 +7,98 @@
.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
+The message is constructed using
+.BR $0 ,
.BR $flagfmt ,
-as described above,
-.BR $args ,
-which should contain the string to be printed explaining
-non-option arguments,
and
+.BR $args .
+The program name is taken from
.BR $0 ,
-the program name
-(see
-.IR rc (1)).
+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
--- a/sys/src/cmd/aux/getflags.c
+++ b/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 @@
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 @@
void
main(int argc, char *argv[])
{- char *flags, *p, buf[512];
+ char *flags, *p, *s, *e, buf[512];
int i, n;
Fmt fmt;
@@ -55,19 +71,38 @@
}
fmtfdinit(&fmt, 1, buf, sizeof buf);
- for(p=flags; p!=(char*)1; p=strchr(p, ',')+1)
- fmtprint(&fmt, "flag%.1s=()\n", p);
+ 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){- fmtprint(&fmt, "flag%C=1\n", ARGC());
+ if(s != e)
+ fmtprint(&fmt, "%.*s=1\n", (int)(e - s), s);
+ else
+ fmtprint(&fmt, "flag%C=1\n", ARGC());
break;
}
n = countargs(p);
- fmtprint(&fmt, "flag%C=(", ARGC());+ 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()));
fmtprint(&fmt, ")\n");
--- a/sys/src/cmd/aux/usage.c
+++ b/sys/src/cmd/aux/usage.c
@@ -31,6 +31,9 @@
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, " [-");