enhancements to AOT/gen-class

AOT now only produces __init.class by default, load uses that class only
must have at least (:gen-class) ns clause to create named class for ns
gen-class can now be called stand-alone
new options allow for control of mapping to implementing namespace,
name of class, loading of implementing namespace, and method name prefix
(doc ns) and (doc gen-class) and http://clojure.org/compilation for details

src/clj/clojure/core.clj

@@ -6,7 +6,7 @@
 ;   the terms of this license.
 ;   You must not remove this notice, or any other, from this software.
 
-(in-ns 'clojure.core)
+(ns clojure.core)
 
 (def
  #^{:arglists '([& items])
@@ -3081,34 +3081,43 @@
   [fmt & args]
   (print (apply format fmt args)))
 
+(def gen-class)
+
 (defmacro ns
   "Sets *ns* to the namespace named by name (unevaluated), creating it
   if needed.  references can be zero or more of: (:refer-clojure ...)
   (:require ...) (:use ...) (:import ...) (:load ...) (:gen-class)
   with the syntax of refer-clojure/require/use/import/load/gen-class
   respectively, except the arguments are unevaluated and need not be
-  quoted, and the :gen-class clause does not take a name (since the
-  class name corresponds to the ns name).  If :refer-clojure is not
-  used, a default (refer 'clojure) is used. The :gen-class directive
-  is ignored when not compiling. If :gen-class is not specified, when
-  compiled the generated class will have only main. Use of ns is
-  preferred to individual calls to in-ns/require/use/import:
-
-  (ns foo
+  quoted. (:gen-class ...), when supplied, defaults to :name
+  corresponding to the ns name, :main true, :impl-ns same as ns, and
+  :init-impl-ns true. All options of gen-class are
+  supported. The :gen-class directive is ignored when not
+  compiling. If :gen-class is not supplied, when compiled only an
+  nsname__init.class will be generated. If :refer-clojure is not used, a
+  default (refer 'clojure) is used.  Use of ns is preferred to
+  individual calls to in-ns/require/use/import:
+
+  (ns foo.bar
     (:refer-clojure :exclude [ancestors printf])
     (:require (clojure.contrib sql sql.tests))
     (:use (my.lib this that))
     (:import (java.util Date Timer Random)
-              (java.sql Connection Statement))
-    (:load \"/mystuff/foo.clj\"))"
+              (java.sql Connection Statement)))"
+
   [name & references]
   (let [process-reference 
         (fn [[kname & args]]
           `(~(symbol "clojure.core" (clojure.core/name kname))
              ~@(map #(list 'quote %) args)))
+        gen-class-clause (first (filter #(= :gen-class (first %)) references))
+        gen-class-call
+          (when gen-class-clause
+            (list* `gen-class :name (.replace (str name) \- \_) :impl-ns name :main true (rest gen-class-clause)))
         references (remove #(= :gen-class (first %)) references)]
     `(do
        (clojure.core/in-ns '~name)
+       ~@(when gen-class-call (list gen-class-call))
        ~@(when (and (not= name 'clojure.core) (not-any? #(= :refer-clojure (first %)) references))
            `((clojure.core/refer '~'clojure.core)))
        ~@(map process-reference references))))
@@ -3313,6 +3322,7 @@
   :reload-all implies :reload and also forces loading of all libs that the
     identified libs directly or indirectly load via require or use
   :verbose triggers printing information about each load, alias, and refer"
+
   [& args]
   (apply load-libs :require args))