/************************************************************* *							     * * 	Macros defining special characters.		     * *							     * *************************************************************/#define NUL	    '\0'#define ASCII_MIN   '\001'#define ASCII_MAX   '\177'/************************************************************* *							     * * 	Macros defining lexical categories.		     * *							     * *************************************************************/#define C_LIT	0   /* individual character literal */#define C_SET	1   /* character set literal	    */#define EOS		0	/* end-of-string */#define LITERAL		1#define OPSTAR		2#define OPALT		3#define OPOPT		4#define OPCAT		5#define LPAREN		6#define RPAREN		7/************************************************************* *							     * * 	Macros for manipulating syntax tree nodes.	     * *							     * *************************************************************/#define lit_type(x)	(x->l_type)#define lit_pos(x)	(x->pos)#define lit_char(x)	((x->val).c)#define lit_cset(x)	((x->val).cset)#define tok_type(x)	(x->type)#define tok_val(x)	(x->val)#define tok_op(x)       (x->val->op)#define tok_lit(x)	((x->val->refs).lit)#define Op(x)		(x->op)#define Lit(x)		((x->refs).lit)#define Child(x)	((x->refs).child)#define Lchild(x)	((x->refs).children.l_child)#define Rchild(x)	((x->refs).children.r_child)#define Nullable(x)	(x->nullable)#define Firstpos(x)	(x->firstposn)#define Lastpos(x)	(x->lastposn)/************************************************************* *							     * *  Macros for manipulating DFA states and sets of states.   * *							     * *************************************************************/#define Positions(x)	(x->posns)#define Final_St(x)	(x->final)#define Goto(x, c)	((x->trans)[c])#define Next_State(x)	((x)->next_state)/*************************************************************/#define new_node(x)	malloc(sizeof(*x))typedef struct {	/* character range literals */	    char low_bd, hi_bd;	} *Ch_Range;typedef struct ch_set {	    /* character set literals */	    Ch_Range elt;	/* rep. as list of ranges */	    struct ch_set *rest;	} *Ch_Set;typedef struct {	/* regular expression literal */	    int pos;	     /* position in syntax tree */	    short l_type;    /* type of literal */	    union {		char c;     /* for character literals */		Ch_Set cset; /* for character sets */	    } val;	} *Re_Lit, *(*Re_lit_array)[];typedef struct pnode {	    int posnum;	    struct pnode *nextpos;	} *Pset, *(*Pset_array)[];typedef struct rnode {	/* regular expression node */	    short op;     /* operator at that node */	    union {		Re_Lit lit;		/* child is a leaf node */		struct rnode *child;	/* child of unary op */		struct {		    struct rnode *l_child; 		    struct rnode *r_child;		} children;		/* children of binary op */	    } refs;	    short nullable;	    Pset firstposn, lastposn;	} *Re_node;typedef struct {			/* token node */	    short type;	    Re_node val;	} *Tok_node;typedef struct snode {	    Re_node val;	    int size;	    struct snode *next;	} *Stack;typedef struct dfa_st {	    Pset posns;	    int final;	    /* 1 if the state is a final state, 0 o/w */	    struct dfa_st *trans[128];	} *Dfa_state;typedef struct dfa_stset {	    Dfa_state st;	    struct dfa_stset *next_state;	} *Dfa_state_set;