1.20.1 Instance variables

chain-current: alien:Cell

Alien reference to current cell of the chain. The notion of current was introduced a long time ago in PCE, while methods only had one argument. Methods needing a second often used current for this purpose.

Now that PCE methods may have any number of arguments there is little use for current. It is advised not to use current.

See also

topic Current

chain-head: alien:Cell

First cell of the chain. When the chain is empty, its value is @nil.

chain <- size: int

Number of elements in the chain. Maintained by the various methods manipulating chains.

chain-tail: alien:Cell

Last cell of the chain. When the chain is empty, the slot has value is @nil and the method fails.