[Maxima-commits] [git] Maxima CAS branch master updated. branch-5_49-base-558-g4c2ce86af

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- Log -----------------------------------------------------------------
commit 4c2ce86affd66fae5d9d9331cc0761725b2155fd
Author: David Scherfgen <d.s...@go...>
Date:   Wed Jun 3 13:00:31 2026 +0200

    Fix SIGN handling of subscripted functions and introduce DECL-IMAGINARYP
    
    This fixes bug #4752.
    
    SIGN, when in complex mode, would only look at the CAAR of an expression, which
    isn't correct for subscripted functions.
    
    To make the code more consistent, introduce DECL-IMAGINARYP along the existing
    DECL-REALP and DECL-COMPLEXP functions and use it instead of $FEATUREP for
    symbols.

diff --git a/src/compar.lisp b/src/compar.lisp
index 4fddd039a..a6776204f 100644
--- a/src/compar.lisp
+++ b/src/compar.lisp
@@ -1373,20 +1373,17 @@ TDNEG TDZERO TDPN) to store it, and also sets SIGN."
 		  (t (sign-any x)))))))
 
 (defun sign-any (x)
+ (let (op)
   (cond ((and *complexsign*
               (symbolp x)
               (decl-complexp x))
          ;; In Complex Mode look for symbols declared to be complex.
-         (if ($featurep x '$imaginary)
-             (setq sign '$imaginary)
-             (setq sign '$complex)))
+         (setq sign (if (decl-imaginaryp x) '$imaginary '$complex)))
         ((and *complexsign*
               (not (atom x))
-              (decl-complexp (caar x)))
-         ;; A function f(x), where f is declared to be imaginary or complex.
-         (if ($featurep (caar x) '$imaginary)
-             (setq sign '$imaginary)
-             (setq sign '$complex)))
+              (decl-complexp (setq op (if (mqapplyp x) (subfunname x) (caar x)))))
+         ;; A function f(x) or f[n](x), where f is declared to be imaginary or complex.
+         (setq sign (if (decl-imaginaryp op) '$imaginary '$complex)))
 	(t
 	 (dcompare x 0)
 	 (if (and $assume_pos
@@ -1399,7 +1396,7 @@ TDNEG TDZERO TDPN) to store it, and also sets SIGN."
 	     (setq sign '$pos))
 	 (setq minus nil evens nil
 	       odds (if (not (member sign '($pos $neg $zero) :test #'eq))
-			(ncons x))))))
+			(ncons x)))))))
 
 (defun sign-mtimes (x)
   (setq x (cdr x))
diff --git a/src/simp.lisp b/src/simp.lisp
index a24af4507..3d907dd5f 100644
--- a/src/simp.lisp
+++ b/src/simp.lisp
@@ -2779,11 +2779,15 @@
 (defun decl-complexp (e)
   (kindp e '$complex))
 
-;; TRUE, if the symbol e is declared to be $real, $rational, $irrational
-;; or $integer
+;; TRUE, if the symbol e is declared to be $real, $rational, $irrational,
+;; $integer, $even or $odd.
 (defun decl-realp (e)
   (kindp e '$real))
 
+;; TRUE, if the symbol e is declared to be $imaginary.
+(defun decl-imaginaryp (e)
+  (kindp e '$imaginary))
+
 ;; WARNING:  Exercise extreme caution when modifying this function!
 ;;
 ;; Richard Fateman and Stavros Macrakis both say that changing the
diff --git a/tests/rtest_sign.mac b/tests/rtest_sign.mac
index e83d91993..6cf9ad656 100644
--- a/tests/rtest_sign.mac
+++ b/tests/rtest_sign.mac
@@ -1665,3 +1665,17 @@ forget(x > -1, x < 1);
 
 is(abs(cos(x)) <= 1);
 true;
+
+/* Bug #4752: "csign doesn't handle subscripted functions like li correctly" */
+
+csign(li[n](x));
+complex;
+
+declare(f, imaginary);
+done;
+
+csign(f[n](x));
+imaginary;
+
+forget(kind(f, imaginary));
+[kind(f, imaginary)];

-----------------------------------------------------------------------

Summary of changes:
 src/compar.lisp      | 15 ++++++---------
 src/simp.lisp        |  8 ++++++--
 tests/rtest_sign.mac | 14 ++++++++++++++
 3 files changed, 26 insertions(+), 11 deletions(-)


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