Instruction set

arraypush A B: Push B onto the end of array A.
arrayunshift A B: Push B onto the front of array A.
arraypop B A: Pop B off of the end of array A.
arrayshift B A: Pop B off the front of array A.
arrayset A I V: Set value V at index I in array A.
arrayget V A I: Get value at index I from array A and store it in V.
arrayremove V A I: Remove value at index I from array A and store it in V.
arraynew A L: Create a new array in A with length of non-negative integer L ($zero is allowed).

structset S K V: Set key symbol (non-negative integer) K in struct S to value V.
structget V S K: Get value from S by key symbol K and store the value in V.
structdelete V S K: Same as structget, however the key-value will be removed from S.
structhas B S K: Set boolean in B depending on whether or not struct S has a value for symbol key K. (Boolean will be integer 0 or 1.)
structnew S: Create a new struct in register S.

call SUB RET: Invoke the subroutine at SUB. RET can be a register for return or $null for no return or ignoring return.
callsymbolic SYM RET: Invoke subroutine identified by the symbol (ID) in register SYM.
calladdress SUB RET: Invoke subroutine at address in register SUB.
tailcall SUB: Same as call but does not grow the stack. Current subroutine’s return will be the return from SUB.
callprimitive SYM RET: Invoke the primitive with symbol (ID) in SYM.
return RET: Return from the current subroutine to the parent. RET can be a register for returning a value or $null.
jump DIFF: Jump DIFF (integer) instructions forwards (positive) or backwards (negative).
goto DEST: Go to DEST (non-negative integer).
if COND DEST: Jump to DEST if COND is truthy (not null and not a zero integer).

catch DEST EXC: Register an exception handler for the current stack frame at destination DEST. If the handler is invoked then the exception will be placed in register EXC (can be $null).
throw EXC: Raise an exception.
clearexception: Clear the current exception and continue execution.
continue: Note: Currently not implemented and likely to be removed. Can be called from an exception handler to attempt to continue from an exception. (Warning: Dangerous!)
rethrow EXC: Reraise an exception (will preserve the stack trace from the exception structure’s point of origin instead of wherever the current handler is).
setexception EXC: Set the current exception into register EXC.

NOTE: May want to make a setconstant instruction available.

setstring A S: Set the string referenced by constant index S into register A.
setinteger A I: Set the integer referenced by constant index S into register A.
setfloat A F: Set the float referenced by constant index S into register A.
setstruct A S: Set the structure referenced by constant index S into register A.
setsymbol A S: At load time: look up string in constant index S, then get the symbol ID from the VM’s symbol table for that string. Upon execution register A will be set to that non-negative integer ID.
setnull A: Set register A to null.

noop: Do nothing for a wee bit of time.
exit STATUS: Exit interpreter with integer status code in STATUS.
symbolicate SYM STR: Look up the symbol ID for the string in STR and update SYM with that value.
move A B: A = B

setlocal N V: Sets a local by symbol name N with value V.
getlocal V N: Gets a local by symbol name N into V.
setglobal N V: Sets a global by symbol name N with value V.
getglobal V N: Gets a global by symbol name N into V.
findlexical V N: Slow stack search operation. Climb the stack searching for a local by symbol name N; if found store in V.

getclosure A: Get the current scope as a closure-structure.
Warning: These will probably be not-very-performant since it will (in the unoptimized case) probably end up compacting and copying the stack.