Hi stu, take a look in clojure protocols. I think that this can help you. http://clojure.org/protocols <http://clojure.org/protocols>
Luiz Costa <http://clojure.org/protocols> On Mon, Mar 14, 2011 at 11:54 PM, stu <stuart.hungerf...@gmail.com> wrote: > Hi, > > I'd like to create a simple library of drawable shapes: lines, circles > and rectangles. I've placed each type of shape in its own namespace > with functions that operate on that shape kind: > > (ns myshapes.line) > > (defn line ... creates new line ...) > > (defn draw ... draws a line ...) > > > To keep things simple a line is just a vector of two points and > circles and rectangles are just structs. > I'd also like to have a sequence of shapes called a picture: > > (ns myshapes.picture) > > (defn picture ... returns picture sequence from args ...) > > (defn draw ... draws whole picture) > > > The problem I have is with the myshapes.picture/draw function. As a > Clojure newb I keep wanting to think of this like a polymorphic > function in the O-O world that relies on each sequence member having a > draw function. > > What's the idiomatic way of handling a situation like this in > Clojure? Do I need to use richer data structures than vectors and > structs for the shapes so they carry some kind of type information? I > can see how a draw multi-method would work if the individual shapes > could be distinguished, or am I going about this the wrong way? > > Any advice much appreciated, > > Stu > > -- > 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 -- 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
