source

Source: <http://enlivend.livejournal.com/36650.html>

using.lisp

CL-USER 46 > (defmacro using ((&rest packages) &body body)
               (let ((packages (mapcar 'find-package packages)))
                 (labels ((symbol-try (symbol package)
                            (multiple-value-bind (symbol status)
                                (find-symbol (symbol-name symbol) package)
                              (when (eq status :external)
                                ;; being lazy here about foo:nil
                                symbol)))
                          (symbol (symbol)
                            (let ((possibles (remove nil (mapcar (lambda (package) (symbol-try symbol package)) packages))))
                              (cond ((cdr possibles)
                                     (error "Symbol ~a exported from more than one package: ~{~a~^, ~}"
                                            symbol (mapcar 'package-name possibles))) 
                                    (possibles
                                     (car possibles)))))
                          (form (form)
                            (loop for thing in form collect
                                  (cond ((symbolp thing)
                                         (or (symbol thing)
                                             thing))
                                        ((consp thing)
                                         (form thing))
                                        (t thing)))))
                   (let ((expansion (form body)))
                     (if (cdr expansion)
                         `(progn ,@expansion)
                       (car expansion))))))
USING

CL-USER 47 > (pprint
              (macroexpand-1 
               '(using (java)
                  (with-open-file (out-stream pathname :direction :output  
                                              :if-exists :supersede  
                                              :element-type :default)  
                    (let*  
                        ((r (jnew |AtomContainerRenderer|  
                                  (jlist  
                                   (jnew |BasicAtomGenerator|)  
                                   (jnew |BasicBondGenerator|)  
                                   (jnew |BasicSceneGenerator|))  
                                  (jnew |AWTFontManager|)))  
                         (vg (jnew |SVGGraphics2D|  
                                   (jcall "getWrappedOutputStream" out-stream)  
                                   (jnew |Dimension| 320 320)))  
                         (adv (jnew |AWTDrawVisitor| vg)))  
                      (jcall "startExport" vg)  
                      (jcall "generateCoordinates"  
                             (jnew |StructureDiagramGenerator| mol))  
                      (jcall "setup" r mol (jnew |Rectangle| 0 0 100 100))  
                      (jcall "paint" r mol adv  
                             (jnew (jconstructor |Rectangle2D$Double| 4)  
                                   10 10 300 300)  
                             +true+)  
                      (jcall "endExport" vg))))
               ))

(WITH-OPEN-FILE (OUT-STREAM PATHNAME :DIRECTION :OUTPUT :IF-EXISTS :SUPERSEDE :ELEMENT-TYPE :DEFAULT)
  (LET* ((R
          (JAVA:JNEW
           |AtomContainerRenderer|
           (JLIST (JAVA:JNEW |BasicAtomGenerator|) (JAVA:JNEW |BasicBondGenerator|) (JAVA:JNEW |BasicSceneGenerator|))
           (JAVA:JNEW |AWTFontManager|)))
         (VG (JAVA:JNEW |SVGGraphics2D| (JAVA:JCALL "getWrappedOutputStream" OUT-STREAM) (JAVA:JNEW |Dimension| 320 320)))
         (ADV (JAVA:JNEW |AWTDrawVisitor| VG)))
    (JAVA:JCALL "startExport" VG)
    (JAVA:JCALL "generateCoordinates" (JAVA:JNEW |StructureDiagramGenerator| MOL))
    (JAVA:JCALL "setup" R MOL (JAVA:JNEW |Rectangle| 0 0 100 100))
    (JAVA:JCALL "paint" R MOL ADV (JAVA:JNEW (JAVA:JCONSTRUCTOR |Rectangle2D$Double| 4) 10 10 300 300) JAVA:+TRUE+)
    (JAVA:JCALL "endExport" VG)))