> | + // Concept extensions
> | + case RID_REQUIRES:
> | + return cp_parser_requires_expression (parser);
> | +
>
> I think you meant here "nested requirements", not "extensions" as in
> "GNU extensions" or "vendor lock-ins". We should continue with "nested
> requirements" then.
This denotes a primary expression, not a nested requirement. I was
trying to subset the requirement like the "Objective-C++ expressions"
comment just below it.
I changed the comment to just "C++ concepts". We may get other primary
expressions related to concepts, although I don't have any planned.
> | +static inline tree
> | +cp_parser_requires_clause (cp_parser *parser)
> | +{
> | + // Parse the constant expression.
> | + tree expr =
> | + cp_parser_binary_expression (parser, false, false, PREC_NOT_OPERATOR,
> NULL);
> | + if (!require_potential_rvalue_constant_expression (expr))
> | + return error_mark_node;
> | + return expr;
>
> The grammar says "constant-expression". You should use
> cp_parser_constant_expression.
When we started talking about requirements, we didn't want the full
breadth of an expression, so I limited it to a logical-or-expression
that is also a constant expression. Commas, assignments, and
conditions at the top-level seemed counter-intuitive.
Do we want to allow any constant expression, or should we just change
the docs to logical-or-expression that is also a constant expression?
Andrew
