I'm sorry. A small correction regarding the last post: --------------------------------------------------------
A simple question (especially for Rich): why not simply make `(x1 x2 x3 ... xn) expand to (clojure.core/apply clojure.core/list (clojure.core/seq (clojure.core/ concat |x1| |x2| |x3| ... |xn|)) ? That way the symmetry is restored and the rules are much simpler. -------------------------------------------------------- Rock On Jun 1, 4:59 pm, Rock <rocco.ro...@gmail.com> wrote: > I've been working on the Wiki lately and I'm stuck on the part about > syntax-quotes (that I had already written) which required some > updating. > > There have been some changes (linked to fully lazy sequences I > suppose) with the way syntax-quotes are expanded. > > It used to work like this: > > ------------------------------ > > For Lists, syntax-quote establishes a template of the corresponding > data structure. Within the template, unqualified forms behave as if > recursively syntax-quoted. > > `(x1 x2 x3 ... xn) > > is interpreted to mean > > (clojure.core/concat |x1| |x2| |x3| ... |xn|) > > where the | | are used to indicate a transformation of an xj as > follows: > > * |form| is interpreted as (clojure.core/list `form), which > contains a syntax-quoted form that must then be further interpreted. > > * |~form| is interpreted as (clojure.core/list form). > > * |~...@form| is interpreted as form. > > If the syntax-quote syntax is nested, the innermost syntax-quoted form > is expanded first. This means that if several ~ occur in a row, the > leftmost one belongs to the innermost syntax-quote. > > ------------------------------ > > but now > > `(x1 x2 x3 ... xn) > > is interpreted to mean > > (clojure.core/seq (clojure.core/concat |x1| |x2| |x3| ... |xn|)) > > [ Rich PLEASE explain why the change ] > > There's nothing shocking about that except for this peculiar behavior: > > `() > > is expanded to > > (clojure.core/list) > > instead of (what you would expect following the rule): > > (clojure.core/seq (clojure.core/concat)) > > Of course the latter would produce nil which is WRONG, so this > asymmetry was introduced (which was NOT there in the past because it > would have been: (clojure.core/concat (clojure.core/list)) ). > > But that's not the end of it. If you do > > `[] > > you get: > > (clojure.core/apply clojure.core/vector (clojure.core/seq > (clojure.core/concat))) > > instead of (what you would expect and is EQUIVALENT): > > (clojure.core/vector) > > The same for the other analogous data structures. > > Now, that does seem a little bizarre. > > A simple question (especially for Rich): > > why not simply make > > `(x1 x2 x3 ... xn) > > expand to > > (clojure.core/apply clojure.core/list (clojure.core/seq (clojure.core/ > concat))) ? > > That way the symmetry is restored and the rules are much simpler. > > Rock --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "Clojure" group. To post to this group, send email to clojure@googlegroups.com Note that posts from new members are moderated - please be patient with your first post. To unsubscribe from this group, send email to clojure+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/clojure?hl=en -~----------~----~----~----~------~----~------~--~---
