The reader basically transforms :: into :namespace/, which means that the remaining part must be an unqualified symbol (i.e. no / in it). The character / is not allowed in unqualified symbols. As the documentation [1] says : "'/' has special meaning, it can be used once in the middle of a symbol to separate the namespace from the name, e.g. my-namespace/foo. '/' by itself names the division function."
Your notation ::junk/junk, assuming your type in namespace my.namespace.junk, would result in the keyword :my.namespace.junk/junk/junk, which is invalid (two /'s). Hence the implied restriction that ::symbol cannot contain a / character. I'm not really sure what you mean about aliases. Keywords stand by themselves (they are literals that evaluate to themselves), they are not aliases for something else. [1] http://clojure.org/reader On 8 March 2013 16:56, nick rothwell <n...@cassiel.com> wrote: > Typing the following at a REPL: > > (str ::junk/junk) > > (where there's no alias for junk) gives me: > > RuntimeException Invalid token: ::junk/junk > clojure.lang.Util.runtimeException (Util.java:219) > RuntimeException Unmatched delimiter: ) clojure.lang.Util.runtimeException > (Util.java:219) > > A couple of things: > > (i) Invalid token seems a bit curt: doesn't it mean something like "no such > namespace alias"? > (ii) A complete aside, but: the interactive REPL obviously isn't > disregarding the rest of the line when it gets a token error. > > Another aside: why does Clojure require "::" for aliases but only ":" for > namespace-qualified keywords? Under what circumstance would I use :junk/junk > in any way other than to mean ::junk/junk (or :my.namespace.junk/junk, given > the appropriate alias)? > > -- > -- > 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 unsubscribe from this group and stop receiving emails from it, send an > email to clojure+unsubscr...@googlegroups.com. > For more options, visit https://groups.google.com/groups/opt_out. > > -- -- 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 unsubscribe from this group and stop receiving emails from it, send an email to clojure+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/groups/opt_out.
