ats_routine_goto_version.h

// Example:
// // Assuming you have a `routine` variable stored somewhere
// rt_begin(routine);
// {
//     // stuff that happens frame 1
// }
// rt_wait(1.0);
// {
//     // after 1.0s, this block runs
// }
// rt_for(0.25);
// {
//     // this block repeats for 0.25s
// }
// rt_step();
// {
//     // the following frame, this block is run
// }
// rt_label(name);
// {
//     if (something)
//         rt_repeat();
//
//     // not run if rt_repeat() was called
//     something_else();
// }
// rt_step();
// {
//     if (another) rt_goto(0); // jumps to label 0
//     if (another2) rt_restart();  // jumps to rt_begin
//     // otherwise the next block will be run next frame
// }
// rt_while(condition_is_true);
// {
//     // this is repeated until condition_is_true is false
// }
// rt_end();

typedef struct rt rt;
struct rt {
    void* at;
    f32 wait_for;
    f32 repeat_for;
};

#define rt_begin(state, delta_time) do { \
    __label__ _rt_start, _rt_end; \
    rt* _rt = &(state); \
    f32 _rt_dt = (delta_time); \
    b32 _rt_mn = 1; \
    if (_rt->wait_for > 0) { \
        _rt->wait_for -= (delta_time); \
        goto _rt_end; \
    } \
    if (_rt->at) goto *_rt->at; \
    _rt->at = &&_rt_start; \
    _rt_start:;

#define rt_step() \
    if (_rt_mn) _rt->at = &&macro_var(_rt_); \
    goto _rt_end; \
    macro_var(_rt_):;

#define rt_label(name) \
    if (_rt_mn) _rt->at = &&name; \
    goto _rt_end; \
    name:;

#define rt_for(time) \
    rt_step(); \
    _rt->repeat_for += _rt_dt; \
    _rt_mn = _rt->repeat_for >= (time); \
    if (_rt_mn) _rt->repeat_for = 0;

#define rt_while(condition) \
    rt_step(); \
    _rt_mn = !(condition); \
    if (!_rt_mn)

#define rt_until(condition) \
    rt_step(); \
    _rt_mn = (condition); \
    if (_rt_mn)

#define rt_wait(time) \
    if (_rt_mn) { _rt->wait_for = (time); _rt->at = &&macro_var(_rt_); } \
    goto _rt_end; \
    macro_var(_rt_):;

#define rt_end() \
    if (_rt_mn) _rt->at = &&_rt_end; \
    goto _rt_end; \
    _rt_end:; } while(0)

// Flow Statements:
// These can be used anywhere between rt_begin and rt_end,
// including if statements, while loops, etc.

// Repeats the block that this is contained within
// Skips the remainder of the block
#define rt_repeat() \
    goto _rt_end;

// Goes to a given block labeled with `rt_label`
#define rt_goto(name) \
    do { \
        _rt->at = &&name; \
        goto _rt_end; \
    } while (0);

// Restarts the entire Coroutine;
// Jumps back to `rt_begin` on the next frame
#define rt_restart() \
    do { \
        _rt->at = 0; \
        _rt->wait_for = 0; \
        _rt->repeat_for = 0; \
        goto _rt_end; \
    } while(0)