[plt-dev] symbol->string and mutability

Why do symbol->string and keyword->string produce mutable strings?  In
so doing, they have to allocate a new string every time.  Is there any
way to get at an immutable string that is not allocated more than
once?  I would prefer that this be the default behavior; R6RS already
specifies that symbol->string produces an immutable string, for
instance.

--Carl