The target variables can be element, array, or structure variables; or pseudovariables.
For array assignments, each target variable must be an array of scalars or structures. The source must be a scalar or an expression with the same number of dimensions and the same bounds for all dimensions as for the target.
Union assignments are not allowed.
In BY NAME structure assignments, each target variable must be a structure. The right-hand side must be a structure reference.
In structure assignments not using BY NAME, each target variable must be a structure. The right-hand side must be a scalar or a structure expression with the same structuring as the target structure:
In structure assignments not using BY NAME, the source may be the null bit string ( ''b ) even if the target structure contains non-computational data. In this case, the assignment is performed as if