[BUG] Commands should never throw Script Errors for offscreen/unseen/unset serials/vars

[ncskrypt]

Nearly all commands currently throw Script Errors when using serials/vars it can't find, due to it being...

• Offscreen
• Hidden / Invisible
• Unset / Doesn't Exist

Script Errors cause everything to abruptly stop, which is not an intended outcome. Players expect particular tasks may fail & return false, but their script continues running.

Instead, all commands involving serials/vars should...

• Display "Not Found" warning (can be @ suppressed/quiet mode)
• Continue running the script
• Return a value of -1 in expressions: -- Allows if ...expression... to still evaluate -1 to false -- Allows if ...expression... = -1 to differentiate between false outcomes: -- Returns 0 ... serial was available to test, and determined to be false -- Returns -1 ... serial was NOT available to test (offscreen/unseen/unset), therefore nothing could be determined so it is false

Couple Examples Below (not an exhaustive list, too many to list...)

attack 'someMobile'

target 'someSerial'

lift 'someItem'

if dead 'myPET'
  // is dead ?
  // is offscreen / not exist ?
  // impossible to know which...
endif

if dead 'myPET' = -1
  // is offscreen / not exist
elseif dead 'myPET'
  // is onscreen and dead
else
  // is alive
endif

if findlayer 'myPET' backpack
  // has backpack (is a pack llama/horse/mule)
else
  // has no backpack ?
  // is offscreen / not exist ?
  // impossible to know which...
endif

if findlayer 'myPET' backpack as 'myPETBag'
  // has backpack (is a pack llama/horse/mule)
elseif findlayer 'myPET' backpack = -1
  // is offscreen / not exist
else
  // is onscreen, but has no backpack
endif