/*  Forms of data list elements  */#define	SIMPLE	1#define NESTED	2/*  data expression block types  */#define	DVALUE	1#define	DVAR	2#define	DNAME	3#define DEXPR	4#define	DERROR	5/*  status codes for integer values  */#define	NORMAL	 1#define MAXPLUS1 2#define MINLESS1 3#define	ERRVAL	 4/*  data types for data statements  */typedef  struct Dvalue    {      char	tag;      char	status;      ftnint	value;    }  dvalue;typedef  struct Dvar    {      char	tag;      struct Dvalue	*valp;    }  dvar;typedef  struct Dname    {      char	tag;      int	len;      char	*repr;    }  dname;typedef  struct Dexpr    {      char	tag;      char	opcode;      union Vexpr	*left;      union Vexpr	*right;    }  dexpr;typedef  struct Derror    {      char	tag;    }  derror;typedef  union Vexpr    {      char	tag;      struct Dvalue	dvalue;      struct Dvar	dvar;      struct Dname	dname;      struct Dexpr	dexpr;      struct Derror	derror;    }  vexpr;typedef  struct Elist    {      struct Elist	*next;      union Delt	*elt;    }  elist;typedef  struct Aelt    {      char	tag;      Namep	var;      struct Vlist	*subs;      struct Rpair	*range;    }  aelt;typedef  struct DoList    {      char	tag;      struct Elist	*elts;      union Vexpr	*dovar;      union Vexpr	*init;      union Vexpr	*limit;      union Vexpr	*step;    }  dolist;typedef  union Delt    {      char	tag;      struct Aelt	simple;      struct DoList	nested;    }  delt;typedef  struct Rpair    {      union Vexpr	*low;      union Vexpr	*high;    }  rpair;typedef  struct ValList    {      struct ValList	*next;      char	status;      int	repl;      Constp	value;    }  vallist;typedef  struct Vlist    {      struct Vlist	*next;      union Vexpr	*val;    }  vlist;typedef  struct DoVars    {      struct DoVars *next;      int len;      char *repr;      dvalue *valp;    }  dovars;/*  Global variables  */extern int badvalue;extern flag overlapflag;/*  Global procedures  */extern frvexpr();extern frvlist();extern elist *revelist();extern vlist *revvlist();extern vlist *prepvexpr();extern elist *preplval();extern delt *mkdlval();extern delt *mkdatado();extern rpair *mkdrange();extern vallist *mkdrval();extern vexpr *evicon();extern vexpr *mkdname();extern expptr ivaltoicon();extern expptr evparam();extern vexpr *evaldname();extern vexpr *mkdexpr();extern vexpr *addivals();extern vexpr *subivals();extern vexpr *mulivals();extern vexpr *divivals();extern vexpr *powivals();extern vexpr *negival();extern expptr convconst();extern savedata();