Add files via upload

Fixed issue relating to the order when nesting derivatives (issues #14).

Author: sjelatex

README.md

@@ -1,4 +1,4 @@
-## README for derivative package v1.3 dated 2023-07-26
+## README for derivative package v1.31 dated 2023-11-04
 
 The package provides a set of commands `\NewDerivative`, `\NewDifferential` etc. that can be used to define a derivative or a differential operator, respectively. The package have already defined several derivatives and differentials:
 

derivative.pdf

@@ -19,7 +19,7 @@
 \RequirePackage{expl3}[2021/11/07]
 \RequirePackage{xparse}[2021/11/07]
 \RequirePackage{l3keys2e}
-\ProvidesExplPackage{derivative}{2023/07/26}{1.3}{Nice and easy derivatives and differentials for LaTeX}
+\ProvidesExplPackage{derivative}{2023/11/04}{1.31}{Nice and easy derivatives and differentials for LaTeX}
 
 \bool_new:N \l__deriv_pkg_italic_bool
 \bool_new:N \l__deriv_pkg_upright_bool
@@ -757,15 +757,9 @@
 	\__deriv_var_bool_seq:cNN { l__deriv_#4_misc_var_clist } \l__deriv_tmpa_seq \l__deriv_var_count_int
 	\int_set:Nn \l__deriv_tmpa_int { \seq_count:N #2 }
 
-	\seq_map_indexed_inline:Nn #2
-	{
-		\tl_put_right:Nx \l__deriv_tmpb_tl
-		{
-			\exp_not:n {##2}
-			\int_compare:nNnF {##1} = { \l__deriv_tmpa_int }
-			{ \__deriv_insert_mskip:nn {#4} { ord_ord } }
-		}
-	}
+	% Temporary store the order argument
+	\tl_set:Nf \l__deriv_tmpb_tl { \seq_use:Nn #2 { \__deriv_insert_mskip:nn {#4} { ord_ord } } }
+	
 	\seq_pop_left:NN \l__deriv_tmpa_seq \l__deriv_tmpc_tl
 	\tl_put_right:Nx #3
 	{
@@ -775,6 +769,7 @@
 		\__deriv_show_order:NT \l__deriv_tmpb_tl
 		{ \__deriv_insert_ord:Nnn \l__deriv_tmpb_tl {#4} { var_ord } }
 	}
+	
 	\str_if_eq:cNT { l__deriv_#4_misc_mixed_order_tl } 1
 	{ \tl_set_eq:cN { l__deriv_#4_misc_mixed_order_tl } \l__deriv_tmpb_tl }
 }