5.12.7 ‘@&’: Join items

During FWEAVE’s output, ‘@&’ joins the items to either side with no spaces or line breaks inbetween.

This command must be distinguished from the preprocessor construction ## (paste tokens together). In a macro definition, ‘a##bc’ creates the single identifier ‘abc’. If one said ‘a@&bc’, two identifiers would be output with no spaces separating them. In simple cases, the results may look identical, but consider how things would differ if abc were itself an FWEB macro that should itself be expanded.