From 4d89d941ae5c674e85ae5402361cb893c07ce65b Mon Sep 17 00:00:00 2001
From: Mark Wooding <mdw@distorted.org.uk>
Date: Sat, 15 Aug 2015 17:55:29 +0100
Subject: [PATCH] src/c-types-impl.lisp: Handle `void' argument lists
 specially.

We'll treat them as equivalent to empty lists.  Otherwise it's just too
easy to declare a message as

	void msg(void)

and end up with a horrible mess when the translator tries to turn that
into a direct method of the form

	void msg(Thing *me, void)

which works less then brilliantly.

And, on output, we'll write an empty list as `void'.  This situation
doesn't arise in the current translator (I think), but might well do in
extensions.
---
 src/c-types-impl.lisp | 48 ++++++++++++++++++++++++++++--------------------
 1 file changed, 28 insertions(+), 20 deletions(-)

diff --git a/src/c-types-impl.lisp b/src/c-types-impl.lisp
index 7dd7b84..be2c055 100644
--- a/src/c-types-impl.lisp
+++ b/src/c-types-impl.lisp
@@ -428,7 +428,13 @@
 (export 'make-function-type)
 (defun make-function-type (subtype arguments)
   "Return a new function type, returning SUBTYPE and accepting ARGUMENTS."
-  (make-instance 'c-function-type :subtype subtype :arguments arguments))
+  (make-instance 'c-function-type :subtype subtype
+		 :arguments (if (and arguments
+				     (null (cdr arguments))
+				     (eq (argument-type (car arguments))
+					 c-type-void))
+				nil
+				arguments)))
 
 ;; Comparison protocol.
 
@@ -440,25 +446,27 @@
 
 ;; C syntax output protocol.
 
-(defmethod pprint-c-type ((type c-function-type) stream kernel)
-  (pprint-c-type (c-type-subtype type) stream
-		 (lambda (stream prio spacep)
-		   (maybe-in-parens (stream (> prio 2))
-		     (when spacep (c-type-space stream))
-		     (funcall kernel stream 2 nil)
-		     (pprint-indent :block 4 stream)
-		     (pprint-logical-block
-			 (stream nil :prefix "(" :suffix ")")
-		       (let ((firstp t))
-			 (dolist (arg (c-function-arguments type))
-			   (if firstp
-			       (setf firstp nil)
-			       (format stream ", ~_"))
-			   (if (eq arg :ellipsis)
-			       (write-string "..." stream)
-			       (pprint-c-type (argument-type arg)
-					      stream
-					      (argument-name arg))))))))))
+(let ((void-arglist (list (make-argument nil c-type-void))))
+  (defmethod pprint-c-type ((type c-function-type) stream kernel)
+    (pprint-c-type (c-type-subtype type) stream
+		   (lambda (stream prio spacep)
+		     (maybe-in-parens (stream (> prio 2))
+		       (when spacep (c-type-space stream))
+		       (funcall kernel stream 2 nil)
+		       (pprint-indent :block 4 stream)
+		       (pprint-logical-block
+			   (stream nil :prefix "(" :suffix ")")
+			 (let ((firstp t))
+			   (dolist (arg (or (c-function-arguments type)
+					    void-arglist))
+			     (if firstp
+				 (setf firstp nil)
+				 (format stream ", ~_"))
+			     (if (eq arg :ellipsis)
+				 (write-string "..." stream)
+				 (pprint-c-type (argument-type arg)
+						stream
+						(argument-name arg)))))))))))
 
 ;; S-expression notation protocol.
 
-- 
2.11.0