Context Variables

More interesting ErgoScript programs contain predicates defined on context, such as:

HEIGHT < 4000000            // address 2fp75qcgMrTNR2vuLhiJYQt

This uses the context variable HEIGHT, representing the height of the block in which the transaction gets mined. A box with this address is "anyone-can-spend" if the blockchain height is less than 4000000 and "no-one-can-spend" otherwise. There are other context variables such as OUTPUTS, INPUTS, minerPubKey. See the documentation for details.