Package-level declarations

Two labels for the statements (module statement_binary, a statementLabellingMode): IN if an argument for the statement is IN, OUT otherwise.

The labels of the statements from those of their arguments (module statement, a statementLabellingMode): a statement is IN if an argument for it is IN, otherwise OUT if one is OUT, otherwise UND if one is UND.

The labels of the statements passed through from those of their arguments (module statement_pass_through, a statementLabellingMode): a statement takes the label of each of its arguments, so it may have several.