#ifndef PARCEL_AST_H
#define PARCEL_AST_H

#include <utility.h>
#include <tokenizer.h>

typedef struct pac_ast                  pac_ast_s;
typedef struct pac_ast_rule             pac_ast_rule_s;
typedef struct pac_ast_variant          pac_ast_variant_s;
typedef struct pac_ast_literal          pac_ast_literal_s;
typedef struct pac_ast_reference        pac_ast_reference_s;
typedef struct pac_ast_item             pac_ast_item_s;

struct pac_ast
{
    usz_t                       num_rules;
    pac_ast_rule_s             *rules;
};

struct pac_ast_rule
{
    char                       *name;

    usz_t                       num_variants;
    pac_ast_variant_s          *variants;
};

struct pac_ast_variant
{
    usz_t                       num_items;
    pac_ast_item_s             *items;
};

// pac_ast_reference: Also called non-terminal, a reference is an item
//  which represents all the contents of another rule.
struct pac_ast_reference
{
    usz_t                       len_name;
    char                       *name;
};

struct pac_ast_literal
{
    usz_t                       length;
    char                       *string;
};

// pac_ast_set_e: An enumeration of all sets known in Parcel's AST.
//
//  Sets are descriptions which describe a rough format of token, like
//  with variable names; the format is known, but the actual name isn't.
typedef enum
{
    PAC_AST_SET_RUNE,
    PAC_AST_SET_WORD,
    PAC_AST_SET_INTEGER,
    PAC_AST_SET_FLOAT
    
} pac_ast_set_e;

typedef enum
{
    PAC_AST_ITEM_INVALID            = 0x00,
    PAC_AST_ITEM_REFERENCE,
    PAC_AST_ITEM_LITERAL,
    PAC_AST_ITEM_SET

} pac_ast_item_e;

struct pac_ast_item
{
    pac_ast_item_e              type;
    union pac_item_data
    {
        pac_ast_literal_s           literal;
        pac_ast_set_e               set;
        pac_ast_reference_s         reference;
    } data;
};

pac_ast_s               pac_grow_ast                    (pac_tlist_s tokens);

#endif // PARCEL_AST_H