From 8ba169bea0a3e9eed9593bdb4832d71a0f5f19a4 Mon Sep 17 00:00:00 2001
From: dos-reis <gdr@axiomatics.org>
Date: Tue, 22 Jan 2008 01:01:51 +0000
Subject: 	Fix AW/102 	* interp/iterator.boot (getIdentity): Properly
 identity the 	algebra empty list.

---
 src/ChangeLog            | 7 +++++++
 src/interp/iterator.boot | 8 ++++++--
 2 files changed, 13 insertions(+), 2 deletions(-)

diff --git a/src/ChangeLog b/src/ChangeLog
index a574d36e..8a3433ae 100644
--- a/src/ChangeLog
+++ b/src/ChangeLog
@@ -1,3 +1,10 @@
+2008-01-21  Gabriel Dos Reis  <gdr@cs.tamu.edu>
+            Waldek Hebisch <hebisch@math.uni.wroc.pl>
+
+	Fix AW/102
+	* interp/iterator.boot (getIdentity): Properly identity the
+	algebra empty list.
+
 2008-01-21  Gabriel Dos Reis  <gdr@cs.tamu.edu>
 
 	Apply patch byStephen Wilson <<wilsons@multiboard.com>
diff --git a/src/interp/iterator.boot b/src/interp/iterator.boot
index 5431b3d9..ff88a8e8 100644
--- a/src/interp/iterator.boot
+++ b/src/interp/iterator.boot
@@ -74,9 +74,13 @@ compReduce1(form is ["REDUCE",op,.,collectForm],m,e,$formalArgList) ==
     [untilCode,.,e]:= comp($until,$Boolean,e)
     finalCode:= substitute(["UNTIL",untilCode],'$until,finalCode)
   [finalCode,m,e]
- 
+
+++ returns the identity element of the `reduction' operation `x'
+++ over a list -- a monoid homomorphism.   
 getIdentity(x,e) ==
-  GETL(x,"THETA") is [y] => y
+  -- The empty list should be indicated by name, not  by its
+  -- object representation.
+  GETL(x,"THETA") is [y] => (y => y; "nil")
  
 numberize x ==
   x=$Zero => 0
-- 
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