typedef enum type_e
{
    application = 0,
    function,
    integer
} type;

typedef struct func_s
{
    char name[16];
} func

typedef struct exp_s
{
    type t;
    union c
    {
        app *a;
        func f;
        int i;
    }
} expression;

typedef struct app_s
{
    expression *f;
    expression *v;
} app;