Where Is It?
The From block is found in the Events drawer of the Blawx toolbox.
What Does It Do?
The From block is used to indicate that a statement became true at a given point in time. It accepts a datetime, and the statement, which can be logically negated.
The From block is the primary way by which you will specify how values changed over time. The initially and ultimately blocks are also used to provide input to the event reasoning system, but most useful information will be provided using the From block.
The from block is a statement block and can be stacked with other statements.
Because of the way the Blawx reasoner translates between datetimes and timestamps for use in event reasoning, the reasoner will fail if From blocks use dates that are calculated recursively on the basis of other dates. For example, if there is a rule that every seventh day is a tuesday, and something becomes true on any tuesday, the reasoner will crash. This is a limitation of the current implementation of event reasoning, and will hopefully be resolved in future versions.