itch.io

It's gonna be a bit complicated but I think this should work:

1. in mev_pause_monsters_status, assign a new script to the script_step variable of the new menu that is created.
2. This new script should check for left/right presses and if so do some stuff; we'll get to that in a little bit. Note that the menu objects already get_keys() every step so you only need to check the input status variables - if(k_l && !p_l) to check for a left press, etc.
3. In mev_pause_monsters_status there's a giant block of code that creates the entire status menu. Break that out (everything inside the with loop) into a new script which takes two arguments monsamp and monid, these are the variables we use to read the selected monster's data - changing them to script arguments lets us reuse this blob of code without having to change it.
4. In the new script, additionally add a new line of code at the top (before the call to ggui_menu_preallocate) which should be ggui_frames = 0; (this lets us reset the menu completely - if you haven't noticed it already the frames are containers for all other GUI elements and resetting the frame counter like this will override the old data with new data without the system noticing)
5. In the now-empty with statement in mev_pause_monsters_status, add a call to that new script that just passes in monsamp and monid as the arguments, and additionally my_monster = other.my_monster so that we pass in the status menu's reference to the party.
6. Now we can fill in those left/right events: they should first update my_monster (add or subtract 1; if below AMP_FIRST_ACTIVE or above-or-equal to AMP_FIRST_ACTIVE+PARTYSIZE_ACTIVE, add/subtract PARTYSIZE_ACTIVE to loop back to the other end of this valid range; repeat the operation if the monster in that AMP slot is empty), then recompute monsamp/monid as currently done in mev_pause_monster_status, and then finally call the menu-setup script with those values.

You can of course extend this to terminals as well, though you'd need a modified version of the left/right check step script that also knows that box the monster is in, and loops the cursor around its range.