Alan Manuel Gloria: > However, having a rule about whether it ends up hooking into a macro > will then mean having an additional rule that has to be remembered by > the user of the new reader, as well as possibly the user of any macro > that has to do scanning of that type. So I propose that either the > reader completely handles infix, or it completely ignores it - no > in-between.
I normally write code so that the macro is never invoked. > > As an aside, at the office we are using a Lisplike with an infix > notation, however I tend to avoid the infix notation except at repl. What is "repl."? > For coding, I use Lisp syntax almost completely, especially after I > finally "got" macros. Well, that's the problem with infix implemented as macros - they work unless you have complex macros, then they sometimes don't work. Yuk. I think in most cases the reader-based approach has serious advantages, simply because it's simple and ALWAYS works. > #|Assumes existing functions: > (bracketaccess-generic obj &rest dimensions) > - accesses a dimensioned object; the number of dimensions > given must match the number of dimensions in the actual object > (get-number-of-dimensions obj) > - determines the number of dimensions in the obj > |# > (define (bracketaccess o d) > (cond > ( (listp o) > (if (eq (get-number-of-dimensions (car o)) (length o)) > (apply #'bracketaccess-generic (append o (list d))) > (append o (list d)) )) > ( (neq 1 (get-number-of-dimensions obj)) > (list o d) ) > ( t > (bracketaccess-generic o d) ))) > #|Creating a congruent setf-macro is left as an exercise to the reader|# > > In the above untested sample, the bracketaccess function never > actually "reaches in" the object except at the final bracketaccess Except that get-number-of-dimensions _does_ need to do a slight reach-in. That's because "a[x][y]" in sweet-expressions maps to: (bracketaccess (bracketaccess a x) y) and so on. That said, the "reach in" is only when you see "bracketaccess", and only when there's a nested "bracketaccess"; this is a highly limited case, and may be okay. --- David A. Wheeler ------------------------------------------------------------------------- This SF.net email is sponsored by: Microsoft Defy all challenges. Microsoft(R) Visual Studio 2008. http://clk.atdmt.com/MRT/go/vse0120000070mrt/direct/01/ _______________________________________________ Readable-discuss mailing list Readable-discuss@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/readable-discuss
