>> Syntax-rules should treat keywords as valid /identifier/s in a
>> production.  I am thinking of the ":" token in Scsh SRE syntax.
>>
> Why?  Keywords are a new type, so they should be used as valid
> identifiers in syntax just like numbers, strings, and booleans
>

Either way.  Per R5RS 7.1.5, one of /pattern datum/ or /pattern
identifier/ needs emending.