Support for optional and parameterized non-terminals

[bterlson]

Non-terminals can be optional and can also have many parameters. I suggest the following syntax:

|NonTerminalName|
|NonTerminalName_opt|
|NonTerminalName[Parameter1]|
|NonTerminalName[Parameter1, ?Parameter2]_opt|

Generally, Non-terminal name, followed by an optional ParameterList (which itself is a comma separated list of parameters surrounded by brackets, where parameters may be prefixed with a ?), followed by an optional "_opt" suffix.

_opt implies an optional non-terminal, Parameter1 is a parameter, and Parameter2 is a parameter whose value is dependent on the occurrence of the parameter in the current LHS.

This aligns with the current typographic practices of the document, though you could argue that _opt should come before the parameter list. I see no reason to do this.

[domenic]

What Ecmarkup should each of those go to?

[bterlson]

|NonTerminalName| -> <emu-nt>NonTerminalName</emu-nt>
|NonTerminalName_opt| -> <emu-nt optional>NonTerminalName</emu-nt>
|NonTerminalName[Parameter1]| -> <emu-nt params="Parameter1">NonTerminalName</emu-nt>
|NonTerminalName[Parameter1, ?Parameter2]_opt| -> <emu-nt params="Parameter1, ?Parameter2" optional>NonTerminalName</emu-nt>