#ifndef AST_H
#define AST_H

struct stmt_node;
struct expr_node;

struct type_node {
    char* type;
};

struct var_decl_node {
    struct type_node type;
    char* ident;

    struct var_decl_node* next;
};

struct group_node {
    struct stmt_node* body_head;
};

struct fn_decl_node {
    struct type_node return_type;
    char* name;
    struct var_decl_node* args_head;
    struct group_node body;
};

struct return_node {
    struct expr_node* ret_val; /* null to return void */
};

struct int_lit_node {
    long long val;
};

struct expr_node {
    enum {
        EXPR_EMPTY,
        EXPR_INT_LIT,
    } type;
    union {
        struct int_lit_node _int_lit;
    } as;
};

struct stmt_node {
    enum {
        STMT_EXPR,
        STMT_VAR_DECL,
        STMT_RETURN,
        STMT_GROUP,
    } type;
    union {
        struct expr_node _expr;
        struct var_decl_node _var_decl;
        struct return_node _return;
        struct group_node _group;
    } as;

    struct stmt_node* next;
};

struct root_node {
    enum {
        ROOT_FN_DECL,
    } type;
    union {
        struct fn_decl_node _fn_decl;
    } as;

    struct root_node* next;
};

void ast_destroy(struct root_node* head);

#endif
