Problem:
When a clone is deleted, its thread is removed from the thread
list; but the index "i" in the execution for-loop will still +1,
making the next thread skipped.
Changes:
Added a flag "isKilled" on a thread;
Set the flag when a thread is removed from the thread list;
reduce the "i" counter if the thread of the current loop is removed.
This saves popping, destroying, recreating, and pushing the stack frame,
and then reassigning the warp mode attribute for every block to block
step in the execution.
Run-time Optimisation
The thread.stackFrames array is accessed all the time to retrieve the
'parent' stack frame. This is done using as index of [this.stack.length
- 1]. However, a lot of the time this evaluated to [-1]. Although this
results in null, which is fine, to get to this javascript actually
defers from a numeric array lookup to an object lookup using the string
"-1". This is roughly 100 times slower to compute and so a simple catch
for negative indexes is well worth the extra check.
* Provide property to Clone to distinguish "original" clones
* Provide method to clone a clone's properties
* Don't report clones in the UI target list
* Add target info to Thread
* Allow hats to skip clones (for green flag)
* Green flag skips clones
* Implement "create clone" and hat
* Pass the runtime to sprites and clones (for start hats)
* Clone disposal; trigger hats after drawable initializes.
* Separate stop threads for target; fix handling of stop button
* Remove extraneous `skipClones` property
* Add global clone limit
* Don't allow a non-clone to delete itself.
* Rename `cloneClone` -> `makeClone`
* Variable updates in runtime.js
* Synchronous drawable initialization (until we put it back to promises)
* Strip out old script glowing in thread management
* Add new tracking mechanism for glowing scripts
* Track parents and use them to determine script glows
* Use top-block for a thread if there's nothing on the stack
* Remove `console.log`
Wang Yu