From d68d655abaef0d14652e07608c633b1ff1feefda Mon Sep 17 00:00:00 2001
From: dos-reis <gdr@axiomatics.org>
Date: Fri, 17 Oct 2008 23:51:50 +0000
Subject: 	Fix AW/271 	* interp/sys-constants.boot ($Field): New. 
 * interp/i-coerce.boot (retract2Specialization): Ignore 	expressions
 whose types do no belong to Field.

---
 src/interp/i-coerce.boot      | 10 ++++++----
 src/interp/sys-constants.boot |  4 ++++
 2 files changed, 10 insertions(+), 4 deletions(-)

(limited to 'src/interp')

diff --git a/src/interp/i-coerce.boot b/src/interp/i-coerce.boot
index 35a0e23b..4a145952 100644
--- a/src/interp/i-coerce.boot
+++ b/src/interp/i-coerce.boot
@@ -214,10 +214,12 @@ retract2Specialization object ==
   type is ['Expression,D] =>
     atom val' => nil          -- certainly not a fraction
     [num,:den] := val'
-    -- coerceRetract already handles case where den = 1
-    num isnt [0,:num] => NIL
-    den isnt [0,:den] => NIL
-    objNewWrap([num,:den],[$QuotientField, D])
+    ofCategory(type,$Field) =>
+      -- coerceRetract already handles case where den = 1
+      num isnt [0,:num] => NIL
+      den isnt [0,:den] => NIL
+      objNewWrap([num,:den],[$QuotientField, D])
+    nil
   type is ['SimpleAlgebraicExtension,k,rep,.] =>
     -- try to retract as an element of rep and see if we can get an
     -- element of k
diff --git a/src/interp/sys-constants.boot b/src/interp/sys-constants.boot
index f6c9ef10..f4468e15 100644
--- a/src/interp/sys-constants.boot
+++ b/src/interp/sys-constants.boot
@@ -331,6 +331,10 @@ $SideEffectFreeFunctionList ==
 
 --% Types
 
+++ The Field category form
+$Field ==
+  '(Field)
+
 ++ The Void domain constructor form
 $Void ==
   '(Void)
-- 
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