--- freem/src/operator.c	2025/02/28 20:06:07	1.2
+++ freem/src/operator.c	2025/05/05 23:09:19	1.11
@@ -1,23 +1,11 @@
 /*
- *                            *
- *                           * *
- *                          *   *
- *                     ***************
- *                      * *       * *
- *                       *  MUMPS  *
- *                      * *       * *
- *                     ***************
- *                          *   *
- *                           * *
- *                            *
- *
- *   operator.c
+ *   $Id: operator.c,v 1.11 2025/05/05 23:09:19 snw Exp $
  *    operators pattern-match, divide, multiply, add, power
  *
  *  
- *   Author: Serena Willis <jpw@coherent-logic.com>
+ *   Author: Serena Willis <snw@coherent-logic.com>
  *    Copyright (C) 1998 MUG Deutschland
- *    Copyright (C) 2020 Coherent Logic Development LLC
+ *    Copyright (C) 2020, 2025 Coherent Logic Development LLC
  *
  *
  *   This file is part of FreeM.
@@ -35,14 +23,38 @@
  *   You should have received a copy of the GNU Affero Public License
  *   along with FreeM.  If not, see <https://www.gnu.org/licenses/>.
  *
+ *   $Log: operator.c,v $
+ *   Revision 1.11  2025/05/05 23:09:19  snw
+ *   Revert errors in E notation parsing
+ *
+ *   Revision 1.10  2025/05/05 23:02:39  snw
+ *   More fixes around E notation
+ *
+ *   Revision 1.9  2025/05/05 22:52:32  snw
+ *   Make E notation error message more appropriate
+ *
+ *   Revision 1.8  2025/05/05 19:34:46  snw
+ *   Fix E notation code to disallow more than one minus sign after the E
+ *
+ *   Revision 1.7  2025/04/10 01:24:38  snw
+ *   Remove C++ style comments
+ *
+ *   Revision 1.6  2025/04/09 19:52:02  snw
+ *   Eliminate as many warnings as possible while building with -Wall
+ *
+ *   Revision 1.5  2025/03/09 19:50:47  snw
+ *   Second phase of REUSE compliance and header reformat
+ *
+ *
+ * SPDX-FileCopyrightText:  (C) 2025 Coherent Logic Development LLC
+ * SPDX-License-Identifier: AGPL-3.0-or-later
  **/
 
 #include "mpsdef.h"
 #include <stdlib.h>
 #include <math.h>
+#include <ctype.h>
 
-void    root ();
-void    mround ();
 int unit (char *str);
 extern void cond_round (char *a, int digits); /* defined in expr.c */
 
@@ -803,8 +815,8 @@ void add (char *a, char *b)				/* string
 		mi = 1;
 		a[0] = ZERO;
 	    }
-	    while (a[mi] == ZERO) {
-		stcpy (&a[mi], &a[mi + 1]);
+	    while (a[(int) mi] == ZERO) {
+		stcpy (&a[(int) mi], &a[((int) mi) + 1]);
 		dpa--;
 	    }
 	    if (dpa < 0)
@@ -832,7 +844,7 @@ void add (char *a, char *b)				/* string
 	    }
 	    a[0] = MINUS;
 	}
-	if (a[mi] == EOL) {
+	if (a[(int) mi] == EOL) {
 	    a[0] = ZERO;
 	    a[1] = EOL;
 	}
@@ -1130,7 +1142,7 @@ void mdiv (char *uu, char *v, short typ)
 
             case '#':
                 snprintf (uu, STRLEN - 1, "%ld\201", (((long) fp_uu) % ((long) fp_v)));
-                //snprintf (uu, STRLEN - 1, "%ld\201", ((long) fp_uu < 0 ? (((long) fp_uu % (long) fp_v) + (long) fp_v) % (long) fp_v : (long) fp_uu % (long) fp_v));
+                /*snprintf (uu, STRLEN - 1, "%ld\201", ((long) fp_uu < 0 ? (((long) fp_uu % (long) fp_v) + (long) fp_v) % (long) fp_v : (long) fp_uu % (long) fp_v)); */
                 break;
         }
         
@@ -1974,13 +1986,34 @@ int numlit (char *str)
 	    }
 	    continue;
 	}
-	if (expflg) {
+	if (expflg) {            
 	    if (ch == MINUS) {
+                /* TODO: revisit this; it breaks string coercion
+                if (str[i + 1] == '-') {                    
+                    merr_raise (INVEXPR);
+                    return (0);
+                }
+                if (!isdigit (str[i + 1])) {
+                    merr_raise (INVEXPR);
+                    return (0);
+                }
+                */
 		expflg = (-expflg);
 		continue;
 	    }
-	    if (ch == PLUS)
+	    if (ch == PLUS) {
+                /* TODO: revisit this; it breaks string coercion
+                if (str[i + 1] == '+') {
+                    merr_raise (INVEXPR);
+                    return (0);
+                }
+                if (!isdigit (str[i + 1])) {
+                    merr_raise (INVEXPR);
+                    return (0);
+                }
+                */
 		continue;
+            }
 	}
 	if ((result = unit (&str[i])))
 	    ch = str[i] = EOL;
@@ -2511,10 +2544,7 @@ void m_op (char *a, char *b, short op)
 	/* rounding */
 	/* 'a' is assumed to be a 'canonic' numeric string  */
 	/* it is rounded to 'digits' fractional digits      */
-void
-mround (a, digits)
-	char   *a;
-	int     digits;
+void mround (char *a, int digits)
 {
     int     ch,
             i,