Plan 9's rc.

not a clear win over byron's,
but at least it has the right syntax.

src/cmd/rc/pfnc.c

@@ -0,0 +1,67 @@
+#include "rc.h"
+#include "exec.h"
+#include "io.h"
+#include "fns.h"
+struct{
+	void (*f)(void);
+	char *name;
+}fname[]={
+	Xappend, "Xappend",
+	Xasync, "Xasync",
+	Xbang, "Xbang",
+	Xclose, "Xclose",
+	Xdup, "Xdup",
+	Xeflag, "Xeflag",
+	Xexit, "Xexit",
+	Xfalse, "Xfalse",
+	Xifnot, "Xifnot",
+	Xjump, "Xjump",
+	Xmark, "Xmark",
+	Xpopm, "Xpopm",
+	Xread, "Xread",
+	Xreturn, "Xreturn",
+	Xtrue, "Xtrue",
+	Xif, "Xif",
+	Xwastrue, "Xwastrue",
+	Xword, "Xword",
+	Xwrite, "Xwrite",
+	Xmatch, "Xmatch",
+	Xcase, "Xcase",
+	Xconc, "Xconc",
+	Xassign, "Xassign",
+	Xdol, "Xdol",
+	Xcount, "Xcount",
+	Xlocal, "Xlocal",
+	Xunlocal, "Xunlocal",
+	Xfn, "Xfn",
+	Xdelfn, "Xdelfn",
+	Xpipe, "Xpipe",
+	Xpipewait, "Xpipewait",
+	Xrdcmds, "Xrdcmds",
+	(void (*)(void))Xerror, "Xerror",
+	Xbackq, "Xbackq",
+	Xpipefd, "Xpipefd",
+	Xsubshell, "Xsubshell",
+	Xdelhere, "Xdelhere",
+	Xfor, "Xfor",
+	Xglob, "Xglob",
+	Xrdfn, "Xrdfn",
+	Xsimple, "Xsimple",
+	Xrdfn, "Xrdfn",
+	Xqdol, "Xqdol",
+0};
+void pfnc(io *fd, thread *t)
+{
+	int i;
+	void (*fn)(void)=t->code[t->pc].f;
+	list *a;
+	pfmt(fd, "pid %d cycle %p %d ", getpid(), t->code, t->pc);
+	for(i=0;fname[i].f;i++) if(fname[i].f==fn){
+		pstr(fd, fname[i].name);
+		break;
+	}
+	if(!fname[i].f) pfmt(fd, "%p", fn);
+	for(a=t->argv;a;a=a->next) pfmt(fd, " (%v)", a->words);
+	pchr(fd, '\n');
+	flush(fd);
+}