From e93416cc05a38b34956e88b9516af5b910d5df19 Mon Sep 17 00:00:00 2001
From: Matthias Benkard <code@mail.matthias.benkard.de>
Date: Sun, 3 Feb 2008 09:46:55 +0100
Subject: Add a compiler macro for SELECTOR.

darcs-hash:4e7f3cf6846d15869487905f52589ee8250bcf5d
---
 Lisp/compiler-macros.lisp   | 20 ++++++++++++++++++++
 Lisp/method-invocation.lisp | 12 ++++++++++++
 2 files changed, 32 insertions(+)

(limited to 'Lisp')

diff --git a/Lisp/compiler-macros.lisp b/Lisp/compiler-macros.lisp
index 72471d5..79fd0a6 100644
--- a/Lisp/compiler-macros.lisp
+++ b/Lisp/compiler-macros.lisp
@@ -66,6 +66,26 @@
       form))
 
 
+;; Optimise all (SELECTOR ...) forms.  This is important in order to
+;; make (FUNCALL (SELECTOR ...) ...) efficient.
+(define-compiler-macro selector (&whole form method-name)
+  (if (and (constantp method-name)
+           (not (and (listp method-name)
+                     (eq 'load-time-value (car method-name)))))
+      `(load-time-value (handler-case
+                            (find-selector ,method-name)
+                          (serious-condition ()
+                            (warn
+                             (make-condition 'simple-style-warning
+                                             :format-control
+                                             "~S designates an unknown ~
+                                               method selector."
+                                             :format-arguments
+                                             (list ,method-name)))
+                            ,method-name)))
+      form))
+
+
 ;; This compiler macro is a bit more complicated than the preceding
 ;; ones.
 (define-compiler-macro invoke (receiver message-start &rest message-components)
diff --git a/Lisp/method-invocation.lisp b/Lisp/method-invocation.lisp
index 92a9c92..c0bad01 100644
--- a/Lisp/method-invocation.lisp
+++ b/Lisp/method-invocation.lisp
@@ -156,6 +156,18 @@ call to __invoke__, or an object of *type* __selector__, to *receiver*.
       ;=> #<GSCBufferString `Mulk.' {5B36087}>
 
 
+## Note:
+
+__selector__ objects are funcallable.  Therefore, the following calls
+are all equivalent:
+
+    (invoke-by-name instance \"stringWithCString:encoding:\" \"Mulk.\" 4)
+    (invoke instance :string-with-c-string \"Mulk.\" :encoding 4)
+    (funcall (selector \"stringWithCString:encoding:\") instance \"Mulk.\" 4)
+
+In fact, using __invoke-by-name__ is discouraged in favour of the latter
+form.
+
 ## Rationale:
 
 Whereas __invoke__ tries to make writing as well as reading method
-- 
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