a = block.extra(blp<,i>)
block.extra(blp<,i>) = a

Get/set the value of the block extra variable at index 1. Use the optional argument i to affect the value of an extra variable at a different index.

Returns:a - value stored in extra variable slot i for block blp
Accepts:a - value to store in extra variable slot for block blp
Arguments:blp - block pointer i - (optional) extra variable index. If not provided, index 1 is assumed.