This function is used to copy the contents of a selected field or named variable to one or more fields, a named variable or each field in a list in a named variable. More information is given in Statement Source/Target Determination regarding the runtime determination of which items to copy to.
You can optionally choose to copy only if a destination is empty and/or only if the source is not empty.
When the destination of the copy is a named variable the copy is only performed one when executing stepwise.
A source and destination named variable field may contain any of the escape sequences described in Escape Sequences. When the destination is not a named variable, a source named variable is unescaped for each field being written.