[Gd-hackers] Gwydion Dylan macro parsing error

[Dustin Voss]

Gwydion Dylan seems to have a bug in its macro processing, which I've  
logged as #7369. The problem is that final semicolons can't be omitted  
from a defining macro call. The bug includes a brief sample to  
demonstrate the problem, and Open Dylan doesn't have a problem.

I think I've fixed it, but I wanted to run it past the group before  
checking it in. The code had special logic for semicolon-separated  
fragment matching vs. comma-separated fragment matching, and there may  
have been a reason for that which I'm unaware of.

Anyway, since the comma-separated fragment matching code works as I  
expect from reading the DRM (p. 151-152, http://www.opendylan.org/books/drm/Patterns) 
, my proposed fix simply applies the same logic to both the semicolon-  
and comma-separated cases.

Here is the diff:

Index: d2c/compiler/parser/support.dylan
===================================================================
--- d2c/compiler/parser/support.dylan	(revision 11673)
+++ d2c/compiler/parser/support.dylan	(working copy)
@@ -425,33 +425,15 @@
  define generic remove-optional-semi-and-end (pattern :: <pattern>)
      => (new-pattern :: <pattern>, found-end? :: <boolean>);

-define method remove-optional-semi-and-end (pattern :: <semicolon- 
pattern>)
+define method remove-optional-semi-and-end
+    (pattern :: type-union(<semicolon-pattern>, <comma-pattern>))
      => (new-pattern :: <pattern>, found-end? :: <boolean>);
-  let right = pattern.pattern-right;
-  if (instance?(right, <name-pattern>)
-	& right.pattern-name.token-symbol == #"end")
-    values(pattern.pattern-left, #t);
-  else
-    let (new-right, found-end?) = remove-optional-semi-and-end(right);
-    if (found-end?)
-      values(make(<semicolon-pattern>,
-		  left: pattern.pattern-left,
-		  right: new-right,
-		  last: ~instance?(new-right, <semicolon-pattern>)),
-	     #t);
-    else
-      values(pattern, #f);
-    end if;
-  end if;
-end method remove-optional-semi-and-end;
-
-define method remove-optional-semi-and-end (pattern :: <comma-pattern>)
-    => (new-pattern :: <pattern>, found-end? :: <boolean>);
    let (new-right, found-end?)
      = remove-optional-semi-and-end(pattern.pattern-right);
    if (found-end?)
-    values(make(<comma-pattern>, left: pattern.pattern-left, right:  
new-right,
-		last: ~instance?(new-right, <comma-pattern>)),
+    values(make(pattern.object-class, left: pattern.pattern-left,
+                right: new-right,
+                last: ~instance?(new-right, pattern.object-class)),
  	   #t);
    else
      values(pattern, #f);