On Tue, 30 Apr 2013 07:28:11 +0800, Alan Manuel Gloria <almkg...@gmail.com> wrote:
> You could use a dynamically-scoped variable (don't remember what they're > called in CL) to pass back the "reason for stopping" return value, and > return the read-in datum from the read implementation. Dynamically-scoped > variables are even run-time-stack lifetimes, so they're highly appropriate > for simulating return values. Thanks for the reply! That's true, but then I'd have to pack/unpack the info, and there's a fair amount of setup/unsetup to work around read's interface. After a certain point, the effort to avoid the work is harder than doing the work :-). What's silly is that (obviously) the underlying Common Lisp *HAS* a mechanism for implementing backquotes and the various ,-operators. The problem is that there's no standard way to directly *invoke* them without also invoking read. But on re-examination, I found that re-implementation was easier than I thought. So I ended up re-implementing just those functions, basically by copying Steele's code. It's public domain, but I'm delighted to give him credit. The result: the Common Lisp sweet-expression implementation now properly handles backquoting and the comma operators (comma-at, comma-dot, and just plain comma). Hooray! --- David A. Wheeler ------------------------------------------------------------------------------ Introducing AppDynamics Lite, a free troubleshooting tool for Java/.NET Get 100% visibility into your production application - at no cost. Code-level diagnostics for performance bottlenecks with <2% overhead Download for free and get started troubleshooting in minutes. http://p.sf.net/sfu/appdyn_d2d_ap1 _______________________________________________ Readable-discuss mailing list Readable-discuss@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/readable-discuss
