From: Brian Harvey <[email protected]> Subject: Re: [r6rs-discuss] What's under the hood? Date: Thu, 24 Sep 2009 23:57:44 -0700
> This position is counterintuitive, I know, because I'm advocating putting in > WG1 an abstraction that, in WG2, would be written in Scheme using lower-level > tools that (my idea of) WG1 just won't have. It might well turn out that you > can't write a really efficient WG1 interpreter in WG1-Scheme, and that > implementations of WG1-Scheme will routinely be written in WG2-Scheme. That > won't bother me, as long as you can write a metacircular WG1 interpreter, > even if it's inefficient. This is a reasonable idea. I feel I can live with that Scheme if it is accompanied by rich srfis. Some srfis may require primitives that can't be expressed in the core Scheme (e.g. network srfi may require socket interface), but it's ok as far as the feature set is implementable in reasonable effort of each implementor. What I care is that such a Scheme still needs to guarantee certain level of portability and interoperability. Case-(in)sensitivity is one of issues related to them. So #!fold-case and #!no-fold-case are, although ugly, needs to in or around the core, for example. (Or we can debate again to choose one; it's not the topic of this post.) Character code is another portability/interoperability issue. I'm ok for an implemenatation to choose whatever character set it's suitable, but we need to agree that if we exchange code, how those character should be interpreted. But then, it occurred to me that even those issues can be delegated to "portability srfi"... a piece of code may declare that it is portable if the implementation satisfies this and this portability srfi, like "srfi-xxx character as unicode codepoint" or "srfi-yyy character as extended grapheme cluster". Or "srfi-zzz metasyntax to switch case sensitivity". (I'm stretching myself here.) Will that lead to dependency headache between srfis? I'm not sure. If many srfis require one particular srfi, that one will be de facto standard. The danger is probably having equally popular srfis that cannot coexist. I guess string mutability and "what is a character?" problem have such danger. --shiro _______________________________________________ r6rs-discuss mailing list [email protected] http://lists.r6rs.org/cgi-bin/mailman/listinfo/r6rs-discuss
