I think it's probably this way because if is built right into the interpreter. So probably the symbol resolution goes something like this, in the compiler:
if symbol is in special forms then emit special form else emit call to user function Many of the built-in functions (even the fn symbol) are defined in clojure's core.clj. These are defined on a clojure level, and as such can be re-defed. However, other functions like def, fn* and if are actually functions built in Java code in the compiler, so you can't really re-order those, just because of they way they are evaluated. I could be wrong however. Timothy On Mon, Mar 14, 2011 at 4:11 AM, Dominikus <dominikus.herzb...@gmail.com> wrote: > I'm not sure I fully understand symbol resolution and the evaluation > strategy of symbol bindings and special forms in Clojure 1.2. > > Let's say I bind 'if' (usually being a special form) to a function: > > user=> (defn if [x] (* x x)) > #'user/if > > However, calling 'if' with an unqualified name does not work. Still, > 'if' works like a special form: > > user=> (if 3) > java.lang.Exception: Too few arguments to if (NO_SOURCE_FILE:74) > user=> (if true 1 2) > 1 > > However, 'if' itself evaluates to the new function on the REPL: > > user=> if > #<user$if user$if@118d189> > > But I can call the redefined 'if' only with a qualified symbol name > > user=> (user/if 3) > 9 > > Why is that? I find it inconsistent to see 'if' evaluating to a > function in the REPL but not in the context of a list; in a list form > I'm forced to use a qualified name to suppress interpretation as a > special form. What is the precise evaluation strategy? (I know, it's > dangerous to redefine special forms. Here, I'm interested in the > evaluation strategy of special forms vs. bound symbols.) > > Cheers, > > Dominikus > > -- > 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 -- “One of the main causes of the fall of the Roman Empire was that–lacking zero–they had no way to indicate successful termination of their C programs.” (Robert Firth) -- 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
