Defined in header <cparse/Parser.hh>

enum class TermRequirementDeclaration
{
    DISALLOWED,
    OPTIONAL,
    MANDATORY
};

A shared vocabulary for grammars that classify whether a construct's terminator is DISALLOWED, OPTIONAL or MANDATORY — for example, whether a statement list must end with a semicolon (MANDATORY), may end with one (OPTIONAL), or must not (DISALLOWED).

Declared inside Parser for name-scoping and to give consuming subclasses a common enum they can name via Parser::TermRequirementDeclaration::MANDATORY rather than defining their own three-valued enum from scratch.

Enumerators

Enumerator	Meaning
DISALLOWED	The construct must not end with the terminator. Consuming one is an error.
OPTIONAL	The construct may or may not end with the terminator. Either form is accepted.
MANDATORY	The construct must end with the terminator. Absence is an error.

Notes

The base Parser class does not reference this enum in any of its methods. Its value is entirely in giving derived grammars a shared name for the concept. If your grammar has no terminator-optionality distinction, ignore the enum.

Example

A grammar that reads a list of statements and classifies the semicolon requirement per statement kind:

using TRD = fedem::parser::Parser::TermRequirementDeclaration;

TRD terminatorFor(StatementKind k)
{
    switch (k)
    {
        case StatementKind::Expression: return TRD::MANDATORY;
        case StatementKind::Block:      return TRD::DISALLOWED;
        case StatementKind::If:         return TRD::OPTIONAL;
    }
    return TRD::MANDATORY;
}

See also

• Parser — the enclosing class.