#define LLALT 9999			/* Alternative is following */

#define LLTERMINAL 1			/* Symbol is a terminal */
#define LLNONTERMINAL 2			/* Symbol is a nonterminal */
#define LLEORULE 0			/* No more alternatives */


struct lhs {				/* LHS of a rule */
	int nr;				/* Nr of the nonterminal */
	struct symbol *rhs;		/* Pointer to RHS */
	char first[LLSETSIZE];		/* First set */
	char follow[LLSETSIZE];		/* Follow set */
	char empty;			/* Set if nonterminal produces empty */
};

struct symbol {				/* Symbol in the RHS of a rule */
	int x;				/* LLTERMINAL or LLNONTERMINAL */
	int nr;				/* Nr of the symbol */
	struct symbol *link;		/* Ptr to next rule with this symbol */
	struct symbol *next;		/* Ptr to next symbol in this rule */
	struct lhs *lhs;		/* Ptr to LHS */
};

struct terminal {			/* Array with links to terminals in a */
	struct symbol *link;		/* rule */	
};

struct nonterminal {			/* Array with links to nt's in a rule */
	struct symbol *link;		/* and pointer to LHS's */
	struct lhs *rule;
};

struct stack_elt {			/* Stack element */
	int flags;			/* Some flags */
	int nr;				/* Nr of symbol */
	int ref_count;			/* Nr of predecessors */
	int hyp_ref_count;		/* Temporary nr of predecessors */
	int matched;			/* Nr of LHS trying to match */
	int nr_nexts;			/* Nr of successors */	
	struct edge *edges;		/* Array of edges to other stack elt's*/
};

/* Possible flags in a stack element */
#define LLHEAD		1		/* Stack element is a head */
#define LLDUMMY		2		/* Stack element is substituted */
#define LLGEN_SEARCH	8		/* Set by 'generate_heads()' */

 
struct edge {				/* Edges of a stack element */
	char flags;			/* Some flags */
	struct stack_elt *ptr;		/* Array with pointers to stack elt's */
};

/* Possible flags in an edge */
#define LLLOOP		 1		/* Belongs to a loop */
#define LLLOOP_SEARCH	 2		/* Used by 'loop()' */
#define LLHYP_SEARCH 	 4		/* Used by 'hyp_run()' */
#define PRINT_SEARCH	 8		/* DEBUG */
#define LLMARK_SEARCH	16		/* Used by 'mark_loop()' */
#define LLYES		32	
#define LLNO		64

#define LLEOSTACK -1			/* Indicates last element of a stack */
#define LLHEADS_BUF_INCR 10		/* Nr of elements the buffer will be */
#define LLCLEANUP_BUF_INCR 25 		/* increased by */
#define LL_VIS_INCR 200

/* Macro's to manipulate bit sets */
#define LLIN(a, i)	((a)[(i)/8] & (1 << ((i) % 8)))
#define LLPUTIN(a, i)	((a)[(i)/8] |= (1 << ((i) % 8)))