CUSTOM Block parameters - local vs global discrepancy

[Turgut Guneysu]

Hi John,

I was testing the 3.4 release when I noticed the following:

• I define a custom block with 3 parameters: foo=1, bar=22, baz=333

  

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• Then edit the block definition and delete the BAZ parameter from the header

  

So the SAY block now must refer to a non-existing local-var BAZ with garbage value 2. And at this point there is no other global var with the name BAZ.

• I define a new global var BAZ. The executed myBlock still refers to non-existing local-var BAZ with garbage value 2 (I believe this to be wrong). The new var’s default value is 0.

  

• Now I assign a value to the global var BAZ = 888. Block executions still show the old values for the custom block (I believe this to be wrong) and also the global var’s correct value.

  

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I think the BAZ handling of the CUSTOM block is in error:

• Once it was deleted in step 2, it’s SCOPE should have been changed to non-local.
• At the very least, in the last step, when BAZ=888 executes, it’s SCOPE should have been changed to global.
• Furthermore, when at the last step, the custom block’s SAY executes, it should have picked up the new context of the BAZ variable.

AND the saga continues:

• I edit the custom block and add another parameter, it defaults to BAZ; I assign the default value 333, and microBlocks crashes !

  

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I have tried this many many times with the same results. So it pretty reproducible.

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[John Maloney]

Thanks. Looks like there is at least one bug here, maybe several.

[John Maloney]

I fixed several bugs associated with this sequence. First, when you delete the parameter “baz” it becomes a local but the value is (correctly) initialized to zero. It’s slightly confusing because there is no “initialize local” block, but in every other way it behaves like a local variable.

Second, when you declare a global “baz” the variable “baz” in the body of myBlock is re-bound to the global.

Finally, it doesn’t crash if you re-add baz as a parameter. And references to baz in the body now refer to the parameter.