column::observable

template<typename Val>
class observable

Column observable.

Template Parameters:

Val – Column data type.

Public Functions

observable(variable<Val> const &obs)

Constructor out of a variable.

Val const &value() const

Compute and retrieve the value of the column.

The column is not computed until the method is called at least once during the dataflow entry processing. Once computed, it is cached for future retrievals.

Returns:

Value of the column.

Val const &operator*() const

Shortcut for value().

Val const *operator->() const

Indirection semantic for non-trivial data types.