--- expr.c.orig	2018-12-17 16:32:21.000000000 +0200
+++ expr.c	2019-06-18 08:30:31.110851666 +0300
@@ -1386,8 +1386,12 @@ readtok ()
     }
   else if (DIGIT(c))
     {
-      while (ISALNUM (c) || c == '#' || c == '@' || c == '_')
-	c = *cp++;
+      unsigned char prevc = c;
+      while (ISALNUM (c) || c == '#' || c == '@' || c == '_' || ((c == '+' || c == '-') && prevc == '#')) 
+        {
+          prevc = c;
+          c = *cp++;
+        }
 
       c = *--cp;
       *cp = '\0';
@@ -1531,6 +1535,8 @@ strlong (num)
   register char *s;
   register unsigned char c;
   int base, foundbase;
+  int digits = 0;
+  char sign = 0;
   intmax_t val;
 
   s = num;
@@ -1569,8 +1575,16 @@ strlong (num)
 
 	  base = val;
 	  val = 0;
+	  digits = 0;
 	  foundbase++;
 	}
+      else if (c == '-' || c == '+')
+        {
+          if (digits > 0 || sign != 0)
+            evalerror (_("invalid number"));
+          
+          sign = c;
+        }
       else if (ISALNUM(c) || (c == '_') || (c == '@'))
 	{
 	  if (DIGIT(c))
@@ -1588,11 +1602,18 @@ strlong (num)
 	    evalerror (_("value too great for base"));
 
 	  val = (val * base) + c;
+	  digits++;
 	}
       else
 	break;
     }
 
+  if (sign == '-')
+    val *= -1;
+  
+  if (digits == 0)
+    evalerror (_("no digits in number"));
+    
   return (val);
 }