Concrete syntax involves both input syntax (for writing and editing, and subsequent parsing) and display format (for browsing on the screen, and publication on paper). The input syntax should preferably be easy to relate to the display format, and sufficiently readable for use in (plain-text) e-mail messages.
Section C.2 below provides a context-free grammar for the proposed CASL input syntax. It has been derived systematically from the `abbreviated' abstract syntax grammar in Appendix A--mainly just by replacing the prefix constructors of the latter by mixfix notation.
Section C.3 provides precedence rules for disambiguation.
Section C.4 specifies the lexical symbols of the proposed concrete syntax.
Finally, Section C.5 shows how comments and various kinds of annotations might be written.