* interp/spaderror.lisp ($numericFailure): Remove.

	(trapNumericErrors): Define for non-GCL RTS.
	Tidy GCL-based definition.
	* algebra/draw.spad.pamphlet: trapNumericErrors now returns a
	value of type Maybe T.
	* algebra/plot.spad.pamphlet: Likewise.
	* algebra/plot3d.spad.pamphlet: Likewise.

5 files changed, 39 insertions, 36 deletions

diff --git a/src/ChangeLog b/src/ChangeLog
index f72f62e3..cd288cbc 100644
--- a/src/ChangeLog
+++ b/src/ChangeLog
@@ -1,5 +1,15 @@
 2011-06-20  Gabriel Dos Reis  <gdr@cs.tamu.edu>
 
+	* interp/spaderror.lisp ($numericFailure): Remove.
+	(trapNumericErrors): Define for non-GCL RTS.
+	Tidy GCL-based definition.
+	* algebra/draw.spad.pamphlet: trapNumericErrors now returns a
+	value of type Maybe T.
+	* algebra/plot.spad.pamphlet: Likewise.
+	* algebra/plot3d.spad.pamphlet: Likewise.
+
+2011-06-20  Gabriel Dos Reis  <gdr@cs.tamu.edu>
+
 	* Makefile.am (OA_GRAPHICS_TARGETS): Fix thinko.
 
 2011-06-20  Gabriel Dos Reis  <gdr@cs.tamu.edu>
diff --git a/src/algebra/draw.spad.pamphlet b/src/algebra/draw.spad.pamphlet
index b5e7bae8..f145330d 100644
--- a/src/algebra/draw.spad.pamphlet
+++ b/src/algebra/draw.spad.pamphlet
@@ -318,10 +318,10 @@ TopLevelDrawFunctionsForCompiledFunctions():
 
     myTrap1: (SF-> SF, SF) -> SF
     myTrap1(ff:SF-> SF, f:SF):SF ==
-      s := trapNumericErrors(ff(f))$Lisp :: Union(SF, "failed")
-      s case "failed" => quietDoubleNaN()$Foreign(Builtin)
-      r:=s::SF
-      r >max()$SF or r < min()$SF => quietDoubleNaN()$Foreign(Builtin)
+      s: Maybe SF := trapNumericErrors(ff(f))$Lisp
+      s case nothing => quietDoubleNaN()$Foreign(Builtin)
+      r := s@SF
+      r > max()$SF or r < min()$SF => quietDoubleNaN()$Foreign(Builtin)
       r
 
     makePt2: (SF,SF) -> Point SF
@@ -493,10 +493,10 @@ TopLevelDrawFunctionsForCompiledFunctions():
 
     myTrap2: ((SF, SF) -> SF, SF, SF) -> SF
     myTrap2(ff:(SF, SF) -> SF, u:SF, v:SF):SF ==
-      s := trapNumericErrors(ff(u, v))$Lisp :: Union(SF, "failed")
-      s case "failed" =>  quietDoubleNaN()$Foreign(Builtin)
-      r:SF := s::SF
-      r >max()$SF or r < min()$SF => quietDoubleNaN()$Foreign(Builtin)
+      s: Maybe SF := trapNumericErrors(ff(u, v))$Lisp
+      s case nothing =>  quietDoubleNaN()$Foreign(Builtin)
+      r := s@SF
+      r > max()$SF or r < min()$SF => quietDoubleNaN()$Foreign(Builtin)
       r
 
     recolor(ptFunc,colFunc) ==
diff --git a/src/algebra/plot.spad.pamphlet b/src/algebra/plot.spad.pamphlet
index d03da277..664e3036 100644
--- a/src/algebra/plot.spad.pamphlet
+++ b/src/algebra/plot.spad.pamphlet
@@ -476,9 +476,9 @@ Plot(): Exports == Implementation where
 
     myTrap: (F-> F, F) -> F
     myTrap(ff:F-> F, f:F):F ==
-      s := trapNumericErrors(ff(f))$Lisp :: Union(F, "failed")
-      s case "failed" => quietDoubleNaN()$Lisp
-      r:F:=s::F
+      s: Maybe F := trapNumericErrors(ff(f))$Lisp
+      s case nothing => quietDoubleNaN()$Lisp
+      r:F := s@F
       r > max()$F or r < min()$F => quietDoubleNaN()$Lisp
       r
 
diff --git a/src/algebra/plot3d.spad.pamphlet b/src/algebra/plot3d.spad.pamphlet
index aa98d794..1ea091a3 100644
--- a/src/algebra/plot3d.spad.pamphlet
+++ b/src/algebra/plot3d.spad.pamphlet
@@ -445,12 +445,9 @@ Plot3D(): Exports == Implementation where
  
     myTrap: (F-> F, F) -> F
     myTrap(ff:F-> F, f:F):F ==
-      s := trapNumericErrors(ff(f))$Lisp :: Union(F, "failed")
-      if (s) case "failed" then
-        r:F := quietDoubleNaN()$Lisp
-      else
-        r:F := s
-      r
+      s: Maybe F := trapNumericErrors(ff(f))$Lisp
+      s case nothing => quietDoubleNaN()$Lisp
+      s
 
     plot(f1:F -> F,f2:F -> F,f3:F -> F,col:F -> F,tRange:R) ==
       p := basicPlot(point(myTrap(f1,#1),myTrap(f2,#1),myTrap(f3,#1),col(#1)),tRange)
diff --git a/src/interp/spaderror.lisp b/src/interp/spaderror.lisp
index 42f65a32..7d65b506 100644
--- a/src/interp/spaderror.lisp
+++ b/src/interp/spaderror.lisp
@@ -1,6 +1,6 @@
 ;; Copyright (c) 1991-2002, The Numerical ALgorithms Group Ltd.
 ;; All rights reserved.
-;; Copyright (C) 2007-2008, Gabriel Dos Reis.
+;; Copyright (C) 2007-2011, Gabriel Dos Reis.
 ;; All rights reserved.
 ;;
 ;; Redistribution and use in source and binary forms, with or without
@@ -43,34 +43,29 @@
  
 ;;(defmacro |trappedSpadEval| (form) form) ;;nop for now
 
-#+:akcl
+#+:gcl
 (defun |resetStackLimits| () (system:reset-stack-limits))
-#-:akcl
+#-:gcl
 (defun |resetStackLimits| () nil)
 
-;; failed union branch --  value returned for numeric failure
-(defconstant |$numericFailure| (cons 1 "failed")) 
-
 (defvar |$oldBreakMode|)
 
-;; following macro evaluates form returning Union(type-of form, "failed")
-
+;; following macro evaluates form returning Maybe type-of form
+#+:gcl
 (defmacro |trapNumericErrors| (form)
   `(let ((|$oldBreakMode| |$BreakMode|)
-         (|$BreakMode| '|trapNumerics|)
+         (|$BreakMode| '|trapNumerics|))
          (val))
-     (setq val (catch '|trapNumerics| ,form))
-     (if (eq val |$numericFailure|) val
-       (cons 0 val))))
+     (catch '|trapNumerics| ,form))
 
-;;;;;; considering this version for kcl
-;;(defmacro |trapNumericErrors| (form)
-;;   `(let ((val))
-;;      (setq val (errorset ,form))
-;;      (if (NULL val) |$numericFailure| (cons 0 (car val)))))
+#-:gcl
+(defmacro |trapNumericErrors| (form)
+  `(handler-bind ((division-by-zero
+		   #'(lambda (c) (declare (ignore c)) |%nothing|)))
+		 ,form))
 
 ;; the following form embeds around the akcl error handler
-#+:akcl
+#+:gcl
 (eval-when
  (load eval)
  (unembed 'system:universal-error-handler)
@@ -85,7 +80,8 @@
                            (|systemError| (error-format error-string args)))
                           ((and (eq |$BreakMode| '|trapNumerics|)
                                 (eq type :ERROR))
-                           (setq |$BreakMode| nil)                         (throw '|trapNumerics| |$numericFailure|))
+                           (setq |$BreakMode| nil)
+			   (throw '|trapNumerics| |%nothing|))
                           ((and (eq |$BreakMode| '|trapNumerics|)
                                 (boundp '|$oldBreakMode|)
                                 (setq |$BreakMode| |$oldBreakMode|)