#ifndef _PLY_NODE_H
#define _PLY_NODE_H

#include <stdint.h>
#include <stdio.h>

#include "sym.h"
#include "type.h"

typedef struct node node_t;

typedef enum kwclass {
	KW_SUBSCRIPT = '[',
	KW_ASSIGN = '=',
	KW_BINOP = 'b',
} kwclass_t;

typedef enum kwarith {
	KW_ADD = '+',
	KW_SUB = '-',
	KW_MUL = '*',
	KW_DIV = '/',
} kwarith_t;

typedef struct keyword {
	kwclass_t class;
	int op;
} keyword_t;

typedef enum ntype {
	N_LIST,
	N_KEYWORD,
	N_IDENT,
	N_NUM,
	N_STRING,
} ntype_t;

struct node {
	node_t *next, *prev, *up;

	ntype_t ntype;
	union {
		node_t *list;
		keyword_t keyword;
		const char *ident;
		int64_t num;
		const char *string;
	};

	type_t *type;
	sym_t *sym;
};

/* debug */
void node_print(node_t *n, FILE *fp);
void node_dump (node_t *n, FILE *fp);

typedef int (*walk_fn)(node_t *, void *);
int node_walk(node_t *n, walk_fn pre, walk_fn post, void *ctx);

int node_replace(node_t *n, node_t *new);


/* constructors */
node_t *node_list  (node_t *head);
node_t *node_vlist (node_t *head, ...);

node_t *node_keyword(kwclass_t class, int op);
node_t *node_ident  (const char *name);
node_t *node_num    (int64_t num);
node_t *node_string (const char *string);

static inline node_t *node_head(node_t *n)
{
	if (!n)
		return NULL;

	for (; n->prev; n = n->prev);

	return n;
}

static inline node_t *node_prev(node_t *n)
{
	return n ? n->prev : NULL;
}

static inline node_t *node_next(node_t *n)
{
	return n ? n->next : NULL;
}

static inline node_t *node_up(node_t *n)
{
	return n ? n->up : NULL;
}

#endif	/* _PLY_NODE_H */