Plan 9's rc.

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

src/cmd/rc/rc.h

@@ -0,0 +1,136 @@
+/*
+ * Plan9 is defined for plan 9
+ * V9 is defined for 9th edition
+ * Sun is defined for sun-os
+ * Please don't litter the code with ifdefs.  The three below (and one in
+ * getflags) should be enough.
+ */
+#define	Plan9
+#ifdef	Plan9
+#include <u.h>
+#include <libc.h>
+#define	NSIG	32
+#define	SIGINT	2
+#define	SIGQUIT	3
+#endif
+#ifdef	V9
+#include <signal.h>
+#include <libc.h>
+#endif
+#ifdef Sun
+#include <signal.h>
+#endif
+#define	YYMAXDEPTH	500
+#ifndef PAREN
+#ifndef YYMAJOR
+#include "x.tab.h"
+#endif
+#endif
+typedef struct tree tree;
+typedef struct word word;
+typedef struct io io;
+typedef union code code;
+typedef struct var var;
+typedef struct list list;
+typedef struct redir redir;
+typedef struct thread thread;
+typedef struct builtin builtin;
+
+struct tree{
+	int type;
+	int rtype, fd0, fd1;		/* details of REDIR PIPE DUP tokens */
+	char *str;
+	int quoted;
+	int iskw;
+	tree *child[3];
+	tree *next;
+};
+tree *newtree(void);
+tree *token(char*, int), *klook(char*), *tree1(int, tree*);
+tree *tree2(int, tree*, tree*), *tree3(int, tree*, tree*, tree*);
+tree *mung1(tree*, tree*), *mung2(tree*, tree*, tree*);
+tree *mung3(tree*, tree*, tree*, tree*), *epimung(tree*, tree*);
+tree *simplemung(tree*), *heredoc(tree*);
+void freetree(tree*);
+tree *cmdtree;
+/*
+ * The first word of any code vector is a reference count.
+ * Always create a new reference to a code vector by calling codecopy(.).
+ * Always call codefree(.) when deleting a reference.
+ */
+union code{
+	void (*f)(void);
+	int i;
+	char *s;
+};
+char *promptstr;
+int doprompt;
+#define	NTOK	8192
+char tok[NTOK];
+#define	APPEND	1
+#define	WRITE	2
+#define	READ	3
+#define	HERE	4
+#define	DUPFD	5
+#define	CLOSE	6
+struct var{
+	char *name;		/* ascii name */
+	word *val;	/* value */
+	int changed;
+	code *fn;		/* pointer to function's code vector */
+	int fnchanged;
+	int pc;			/* pc of start of function */
+	var *next;	/* next on hash or local list */
+};
+var *vlook(char*), *gvlook(char*), *newvar(char*, var*);
+#define	NVAR	521
+var *gvar[NVAR];				/* hash for globals */
+#define	new(type)	((type *)emalloc(sizeof(type)))
+char *emalloc(long);
+void *Malloc(ulong);
+void efree(char*);
+#define	NOFILE	128		/* should come from <param.h> */
+struct here{
+	tree *tag;
+	char *name;
+	struct here *next;
+};
+int mypid;
+/*
+ * Glob character escape in strings:
+ *	In a string, GLOB must be followed by *?[ or GLOB.
+ *	GLOB* matches any string
+ *	GLOB? matches any single character
+ *	GLOB[...] matches anything in the brackets
+ *	GLOBGLOB matches GLOB
+ */
+#define	GLOB	((char)0x01)
+/*
+ * onebyte(c), twobyte(c), threebyte(c)
+ * Is c the first character of a one- two- or three-byte utf sequence?
+ */
+#define	onebyte(c)	((c&0x80)==0x00)
+#define	twobyte(c)	((c&0xe0)==0xc0)
+#define	threebyte(c)	((c&0xf0)==0xe0)
+char **argp;
+char **args;
+int nerror;		/* number of errors encountered during compilation */
+int doprompt;		/* is it time for a prompt? */
+/*
+ * Which fds are the reading/writing end of a pipe?
+ * Unfortunately, this can vary from system to system.
+ * 9th edition Unix doesn't care, the following defines
+ * work on plan 9.
+ */
+#define	PRD	0
+#define	PWR	1
+extern char *Rcmain(), Fdprefix[];
+#define	register
+/*
+ * How many dot commands have we executed?
+ * Used to ensure that -v flag doesn't print rcmain.
+ */
+int ndot;
+char *getstatus(void);
+int lastc;
+int lastword;