%%% -*- coding: utf-8 -*-
%% ----------------------------------------------------------------------------
%% Functional: Intuitive Functional Programming Interface for LaTeX2
%% Copyright : 2022-2023 (c) Jianrui Lyu <tolvjr@163.com>
%% Repository: https://github.com/lvjr/functional
%% Repository: https://bitbucket.org/lvjr/functional
%% License   : The LaTeX Project Public License 1.3c
%% ----------------------------------------------------------------------------

%%% --------------------------------------------------------
%%> \section{Interfaces for Functional Programming (Prg)}
%%% --------------------------------------------------------

\NeedsTeXFormat{LaTeX2e}[2018-04-01]

\RequirePackage{expl3}
\ProvidesExplPackage{functional}{2024-02-16}{2024A}
  {^^JIntuitive Functional Programming Interface for LaTeX2}

\cs_generate_variant:Nn \iow_log:n { V }
\cs_generate_variant:Nn \str_set:Nn { Ne }
\cs_generate_variant:Nn \tl_log:n { e }
\cs_generate_variant:Nn \tl_set:Nn { Ne }

\prg_generate_conditional_variant:Nnn \str_if_eq:nn { Ve } { TF }

\cs_new_protected:Npn \__fun_ignore_spaces_on:
  {
    \ExplSyntaxOn
    \char_set_catcode_math_subscript:N \_
    \char_set_catcode_other:N \:
  }
\cs_set_eq:NN \IgnoreSpacesOn \__fun_ignore_spaces_on:
\cs_set_eq:NN \IgnoreSpacesOff \ExplSyntaxOff

%%% --------------------------------------------------------
%%> \subsection{Setting Functional Package}
%%% --------------------------------------------------------

\bool_new:N \l__fun_scoping_bool

\cs_new_protected:Npn \__fun_scoping_true:
  {
    \cs_set_eq:NN \__fun_group_begin: \group_begin:
    \cs_set_eq:NN \__fun_group_end: \group_end:
  }

\cs_new_protected:Npn \__fun_scoping_false:
  {
    \cs_set_eq:NN \__fun_group_begin: \scan_stop:
    \cs_set_eq:NN \__fun_group_end: \scan_stop:
  }

\cs_new_protected:Npn \__fun_scoping_set:
  {
    \bool_if:NTF \l__fun_scoping_bool
      { \__fun_scoping_true: } { \__fun_scoping_false: }
  }

\bool_new:N \l__fun_tracing_bool
\tl_new:N \l__tracing_text_tl

\cs_new_protected:Npn \__fun_tracing_log_on:n #1
  {
    \tl_set:Ne \l__tracing_text_tl
      {
        \prg_replicate:nn
          { \int_eval:n { (\g__fun_nesting_level_int - 1) * 4 } } { ~ }
      }
    \tl_put_right:Nn \l__tracing_text_tl { #1 }
    \iow_log:V \l__tracing_text_tl
  }
\cs_generate_variant:Nn \__fun_tracing_log_on:n { e, V }

\cs_new_protected:Npn \__fun_tracing_log_off:n #1 { }
\cs_new_protected:Npn \__fun_tracing_log_off:e #1 { }
\cs_new_protected:Npn \__fun_tracing_log_off:V #1 { }

\cs_new_protected:Npn \__fun_tracing_true:
  {
    \cs_set_eq:NN \__fun_tracing_log:n \__fun_tracing_log_on:n
    \cs_set_eq:NN \__fun_tracing_log:e \__fun_tracing_log_on:e
    \cs_set_eq:NN \__fun_tracing_log:V \__fun_tracing_log_on:V
  }

\cs_new_protected:Npn \__fun_tracing_false:
  {
    \cs_set_eq:NN \__fun_tracing_log:n \__fun_tracing_log_off:n
    \cs_set_eq:NN \__fun_tracing_log:e \__fun_tracing_log_off:e
    \cs_set_eq:NN \__fun_tracing_log:V \__fun_tracing_log_off:V
  }

\cs_new_protected:Npn \__fun_tracing_set:
  {
    \bool_if:NTF \l__fun_tracing_bool
      { \__fun_tracing_true: } { \__fun_tracing_false: }
  }

\keys_define:nn { functional }
  {
    scoping .bool_set:N = \l__fun_scoping_bool,
    tracing .bool_set:N = \l__fun_tracing_bool,
  }

\NewDocumentCommand \Functional { m }
  {
    \keys_set:nn { functional } { #1 }
    \__fun_scoping_set:
    \__fun_tracing_set:
  }

\Functional { scoping = false, tracing = false }

%%% --------------------------------------------------------
%%> \subsection{Creating New Functions and Conditionals}
%%% --------------------------------------------------------

\tl_new:N \gResultTl
\int_new:N \l__fun_arg_count_int
\tl_new:N \l__fun_parameters_defined_tl
\tl_const:Nn \c__fun_parameter_defined_i__tl     {  } % no argument
\tl_const:Nn \c__fun_parameter_defined_i_i_tl    { #1 }
\tl_const:Nn \c__fun_parameter_defined_i_ii_tl   { #1 #2 }
\tl_const:Nn \c__fun_parameter_defined_i_iii_tl  { #1 #2 #3 }
\tl_const:Nn \c__fun_parameter_defined_i_iv_tl   { #1 #2 #3 #4 }
\tl_const:Nn \c__fun_parameter_defined_i_v_tl    { #1 #2 #3 #4 #5 }
\tl_const:Nn \c__fun_parameter_defined_i_vi_tl   { #1 #2 #3 #4 #5 #6 }
\tl_const:Nn \c__fun_parameter_defined_i_vii_tl  { #1 #2 #3 #4 #5 #6 #7 }
\tl_const:Nn \c__fun_parameter_defined_i_viii_tl { #1 #2 #3 #4 #5 #6 #7 #8 }
\tl_const:Nn \c__fun_parameter_defined_i_ix_tl   { #1 #2 #3 #4 #5 #6 #7 #8 #9 }
\tl_new:N \l__fun_parameters_called_tl
\tl_const:Nn \c__fun_parameter_called_i_i_tl   { {#1} }
\tl_const:Nn \c__fun_parameter_called_i_ii_tl  { {#1}{#2} }
\tl_const:Nn \c__fun_parameter_called_i_iii_tl { {#1}{#2}{#3} }
\tl_const:Nn \c__fun_parameter_called_i_iv_tl  { {#1}{#2}{#3}{#4} }
\tl_const:Nn \c__fun_parameter_called_i_v_tl   { {#1}{#2}{#3}{#4}{#5} }
\tl_const:Nn \c__fun_parameter_called_i_vi_tl  { {#1}{#2}{#3}{#4}{#5}{#6} }
\tl_const:Nn \c__fun_parameter_called_i_vii_tl { {#1}{#2}{#3}{#4}{#5}{#6}{#7} }
\tl_new:N \l__fun_parameters_true_tl
\tl_new:N \l__fun_parameters_false_tl
\tl_const:Nn \c__fun_parameter_called_i_tl    { {#1} }
\tl_const:Nn \c__fun_parameter_called_ii_tl   { {#2} }
\tl_const:Nn \c__fun_parameter_called_iii_tl  { {#3} }
\tl_const:Nn \c__fun_parameter_called_iv_tl   { {#4} }
\tl_const:Nn \c__fun_parameter_called_v_tl    { {#5} }
\tl_const:Nn \c__fun_parameter_called_vi_tl   { {#6} }
\tl_const:Nn \c__fun_parameter_called_vii_tl  { {#7} }
\tl_const:Nn \c__fun_parameter_called_viii_tl { {#8} }
\tl_const:Nn \c__fun_parameter_called_ix_tl   { {#9} }

%% #1: function name; #2: argument specification; #3 function body
\cs_new_protected:Npn \__fun_new_function:Nnn #1 #2 #3
  {
    \int_set:Nn \l__fun_arg_count_int { \tl_count:n {#2} } % spaces are ignored
    \tl_set_eq:Nc \l__fun_parameters_defined_tl
      { c__fun_parameter_defined_i_ \int_to_roman:n { \l__fun_arg_count_int } _tl }
    \exp_last_unbraced:NcV \cs_new_protected:Npn
      { __fun_defined_ \cs_to_str:N #1 : w }
      \l__fun_parameters_defined_tl
      {
        \__fun_group_begin:
        \tl_gclear:N \gResultTl
        #3
        \__fun_tracing_log:e { [O] ~ \exp_not:V \gResultTl }
        \__fun_group_end:
      }
    \use:c { __fun_new_with_arg_ \int_to_roman:n { \l__fun_arg_count_int } :NnV }
      #1 {#2} \l__fun_parameters_defined_tl
  }
\cs_generate_variant:Nn \__fun_new_function:Nnn { cne }

\cs_set_eq:NN \prgNewFunction \__fun_new_function:Nnn
\cs_set_eq:NN \PrgNewFunction \__fun_new_function:Nnn

\tl_new:N \g__fun_last_result_tl
\int_new:N \l__fun_cond_arg_count_int

%% #1: function name; #2: argument specification; #3 function body
\cs_new_protected:Npn \__fun_new_conditional:Nnn #1 #2 #3
  {
    \__fun_new_function:Nnn #1 { #2 } { #3 }
    \int_set:Nn \l__fun_cond_arg_count_int { \tl_count:n {#2} }
    \tl_set_eq:Nc \l__fun_parameters_called_tl
      {
        c__fun_parameter_called_i_
        \int_to_roman:n { \l__fun_cond_arg_count_int } _tl
      }
    %% define function \FooIfBarT for #1=\FooIfBar
    \tl_set_eq:Nc \l__fun_parameters_true_tl
      {
        c__fun_parameter_called_
        \int_to_roman:n { \l__fun_cond_arg_count_int + 1 } _tl
      }
    \__fun_new_function:cne { \cs_to_str:N #1 T } { #2 n }
      {
        #1 \exp_not:V \l__fun_parameters_called_tl
        \exp_not:n
          {
            \tl_set_eq:NN \g__fun_last_result_tl \gResultTl
            \tl_gclear:N \gResultTl
            \exp_last_unbraced:NV \bool_if:NT \g__fun_last_result_tl
          }
        \exp_not:V \l__fun_parameters_true_tl
      }
    %% define function \FooIfBarF for #1=\FooIfBar
    \tl_set_eq:Nc \l__fun_parameters_false_tl
      {
        c__fun_parameter_called_
        \int_to_roman:n { \l__fun_cond_arg_count_int + 1 } _tl
      }
    \__fun_new_function:cne { \cs_to_str:N #1 F } { #2 n }
      {
        #1 \exp_not:V \l__fun_parameters_called_tl
        \exp_not:n
          {
            \tl_set_eq:NN \g__fun_last_result_tl \gResultTl
            \tl_gclear:N \gResultTl
            \exp_last_unbraced:NV \bool_if:NF \g__fun_last_result_tl
          }
        \exp_not:V \l__fun_parameters_false_tl
      }
    %% define function \FooIfBarTF for #1=\FooIfBar
    \tl_set_eq:Nc \l__fun_parameters_true_tl
      {
        c__fun_parameter_called_
        \int_to_roman:n { \l__fun_cond_arg_count_int + 1 } _tl
      }
    \tl_set_eq:Nc \l__fun_parameters_false_tl
      {
        c__fun_parameter_called_
        \int_to_roman:n { \l__fun_cond_arg_count_int + 2 } _tl
      }
    \__fun_new_function:cne { \cs_to_str:N #1 TF } { #2 n n }
      {
        #1 \exp_not:V \l__fun_parameters_called_tl
        \exp_not:n
          {
            \tl_set_eq:NN \g__fun_last_result_tl \gResultTl
            \tl_gclear:N \gResultTl
            \exp_last_unbraced:NV \bool_if:NTF \g__fun_last_result_tl
          }
        \exp_not:V \l__fun_parameters_true_tl
        \exp_not:V \l__fun_parameters_false_tl
      }
  }

\cs_set_eq:NN \prgNewConditional \__fun_new_conditional:Nnn
\cs_set_eq:NN \PrgNewConditional \__fun_new_conditional:Nnn

\int_new:N \g__fun_nesting_level_int

%% #1: function name; #2: argument specifications; #3 parameters tl defined
%% Some times we need to create a function without arguments
\cs_new_protected:Npn \__fun_new_with_arg_:Nnn #1 #2 #3
  {
    \cs_new_protected:Npn #1 #3
      {
        \int_gincr:N \g__fun_nesting_level_int
        \__fun_evaluate:Nn #1 {#2}
        \int_gdecr:N \g__fun_nesting_level_int
        \__fun_return_result:
      }
  }
\cs_generate_variant:Nn \__fun_new_with_arg_:Nnn { NnV }

%% #1: function name; #2: argument specifications; #3 parameters tl defined
\cs_new_protected:Npn \__fun_new_with_arg_i:Nnn #1 #2 #3
  {
    \cs_new_protected:Npn #1 #3
      {
        \int_gincr:N \g__fun_nesting_level_int
        \__fun_one_argument_gset:nn { 1 } { ##1 }
        \__fun_evaluate:Nn #1 {#2}
        \int_gdecr:N \g__fun_nesting_level_int
        \__fun_return_result:
      }
  }
\cs_generate_variant:Nn \__fun_new_with_arg_i:Nnn { NnV }

%% #1: function name; #2: argument specifications; #3 parameters tl defined
\cs_new_protected:Npn \__fun_new_with_arg_ii:Nnn #1 #2 #3
  {
    \cs_new_protected:Npn #1 #3
      {
        \int_gincr:N \g__fun_nesting_level_int
        \__fun_one_argument_gset:nn { 1 } { ##1 }
        \__fun_one_argument_gset:nn { 2 } { ##2 }
        \__fun_evaluate:Nn #1 {#2}
        \int_gdecr:N \g__fun_nesting_level_int
        \__fun_return_result:
      }
  }
\cs_generate_variant:Nn \__fun_new_with_arg_ii:Nnn { NnV }

%% #1: function name; #2: argument specifications; #3 parameters tl defined
\cs_new_protected:Npn \__fun_new_with_arg_iii:Nnn #1 #2 #3
  {
    \cs_new_protected:Npn #1 #3
      {
        \int_gincr:N \g__fun_nesting_level_int
        \__fun_one_argument_gset:nn { 1 } { ##1 }
        \__fun_one_argument_gset:nn { 2 } { ##2 }
        \__fun_one_argument_gset:nn { 3 } { ##3 }
        \__fun_evaluate:Nn #1 {#2}
        \int_gdecr:N \g__fun_nesting_level_int
        \__fun_return_result:
      }
  }
\cs_generate_variant:Nn \__fun_new_with_arg_iii:Nnn { NnV }

%% #1: function name; #2: argument specifications; #3 parameters tl defined
\cs_new_protected:Npn \__fun_new_with_arg_iv:Nnn #1 #2 #3
  {
    \cs_new_protected:Npn #1 #3
      {
        \int_gincr:N \g__fun_nesting_level_int
        \__fun_one_argument_gset:nn { 1 } { ##1 }
        \__fun_one_argument_gset:nn { 2 } { ##2 }
        \__fun_one_argument_gset:nn { 3 } { ##3 }
        \__fun_one_argument_gset:nn { 4 } { ##4 }
        \__fun_evaluate:Nn #1 {#2}
        \int_gdecr:N \g__fun_nesting_level_int
        \__fun_return_result:
      }
  }
\cs_generate_variant:Nn \__fun_new_with_arg_iv:Nnn { NnV }

%% #1: function name; #2: argument specifications; #3 parameters tl defined
\cs_new_protected:Npn \__fun_new_with_arg_v:Nnn #1 #2 #3
  {
    \cs_new_protected:Npn #1 #3
      {
        \int_gincr:N \g__fun_nesting_level_int
        \__fun_one_argument_gset:nn { 1 } { ##1 }
        \__fun_one_argument_gset:nn { 2 } { ##2 }
        \__fun_one_argument_gset:nn { 3 } { ##3 }
        \__fun_one_argument_gset:nn { 4 } { ##4 }
        \__fun_one_argument_gset:nn { 5 } { ##5 }
        \__fun_evaluate:Nn #1 {#2}
        \int_gdecr:N \g__fun_nesting_level_int
        \__fun_return_result:
      }
  }
\cs_generate_variant:Nn \__fun_new_with_arg_v:Nnn { NnV }

%% #1: function name; #2: argument specifications; #3 parameters tl defined
\cs_new_protected:Npn \__fun_new_with_arg_vi:Nnn #1 #2 #3
  {
    \cs_new_protected:Npn #1 #3
      {
        \int_gincr:N \g__fun_nesting_level_int
        \__fun_one_argument_gset:nn { 1 } { ##1 }
        \__fun_one_argument_gset:nn { 2 } { ##2 }
        \__fun_one_argument_gset:nn { 3 } { ##3 }
        \__fun_one_argument_gset:nn { 4 } { ##4 }
        \__fun_one_argument_gset:nn { 5 } { ##5 }
        \__fun_one_argument_gset:nn { 6 } { ##6 }
        \__fun_evaluate:Nn #1 {#2}
        \int_gdecr:N \g__fun_nesting_level_int
        \__fun_return_result:
      }
  }
\cs_generate_variant:Nn \__fun_new_with_arg_vi:Nnn { NnV }

%% #1: function name; #2: argument specifications; #3 parameters tl defined
\cs_new_protected:Npn \__fun_new_with_arg_vii:Nnn #1 #2 #3
  {
    \cs_new_protected:Npn #1 #3
      {
        \int_gincr:N \g__fun_nesting_level_int
        \__fun_one_argument_gset:nn { 1 } { ##1 }
        \__fun_one_argument_gset:nn { 2 } { ##2 }
        \__fun_one_argument_gset:nn { 3 } { ##3 }
        \__fun_one_argument_gset:nn { 4 } { ##4 }
        \__fun_one_argument_gset:nn { 5 } { ##5 }
        \__fun_one_argument_gset:nn { 6 } { ##6 }
        \__fun_one_argument_gset:nn { 7 } { ##7 }
        \__fun_evaluate:Nn #1 {#2}
        \int_gdecr:N \g__fun_nesting_level_int
        \__fun_return_result:
      }
  }
\cs_generate_variant:Nn \__fun_new_with_arg_vii:Nnn { NnV }

%% #1: function name; #2: argument specifications; #3 parameters tl defined
\cs_new_protected:Npn \__fun_new_with_arg_viii:Nnn #1 #2 #3
  {
    \cs_new_protected:Npn #1 #3
      {
        \int_gincr:N \g__fun_nesting_level_int
        \__fun_one_argument_gset:nn { 1 } { ##1 }
        \__fun_one_argument_gset:nn { 2 } { ##2 }
        \__fun_one_argument_gset:nn { 3 } { ##3 }
        \__fun_one_argument_gset:nn { 4 } { ##4 }
        \__fun_one_argument_gset:nn { 5 } { ##5 }
        \__fun_one_argument_gset:nn { 6 } { ##6 }
        \__fun_one_argument_gset:nn { 7 } { ##7 }
        \__fun_one_argument_gset:nn { 8 } { ##8 }
        \__fun_evaluate:Nn #1 {#2}
        \int_gdecr:N \g__fun_nesting_level_int
        \__fun_return_result:
      }
  }
\cs_generate_variant:Nn \__fun_new_with_arg_viii:Nnn { NnV }

%% #1: function name; #2: argument specifications; #3 parameters tl defined
\cs_new_protected:Npn \__fun_new_with_arg_ix:Nnn #1 #2 #3
  {
    \cs_new_protected:Npn #1 #3
      {
        \int_gincr:N \g__fun_nesting_level_int
        \__fun_one_argument_gset:nn { 1 } { ##1 }
        \__fun_one_argument_gset:nn { 2 } { ##2 }
        \__fun_one_argument_gset:nn { 3 } { ##3 }
        \__fun_one_argument_gset:nn { 4 } { ##4 }
        \__fun_one_argument_gset:nn { 5 } { ##5 }
        \__fun_one_argument_gset:nn { 6 } { ##6 }
        \__fun_one_argument_gset:nn { 7 } { ##7 }
        \__fun_one_argument_gset:nn { 8 } { ##8 }
        \__fun_one_argument_gset:nn { 9 } { ##9 }
        \__fun_evaluate:Nn #1 {#2}
        \int_gdecr:N \g__fun_nesting_level_int
        \__fun_return_result:
      }
  }
\cs_generate_variant:Nn \__fun_new_with_arg_ix:Nnn { NnV }

\tl_new:N \l__fun_argtype_tl
\tl_const:Nn \c__fun_argtype_e_tl { e }
\tl_const:Nn \c__fun_argtype_E_tl { E }
\tl_const:Nn \c__fun_argtype_m_tl { m }
\tl_const:Nn \c__fun_argtype_M_tl { M }
\tl_const:Nn \c__fun_argtype_n_tl { n }
\tl_const:Nn \c__fun_argtype_N_tl { N }
\tl_new:N \l__fun_argument_tl

%% #1: function name; #2: argument specifications
\cs_new_protected:Npn \__fun_evaluate:Nn #1 #2
  {
    \__fun_argtype_index_gzero:
    \__fun_arguments_gclear:
    \tl_map_variable:nNn { #2 } \l__fun_argtype_tl % spaces are ignored
      {
        \__fun_argtype_index_gincr:
        \__fun_one_argument_get:eN { \__fun_argtype_index_use: } \l__fun_argument_tl
        \tl_case:Nn \l__fun_argtype_tl
          {
            \c__fun_argtype_e_tl
              {
                \__fun_evaluate_all_and_put_argument:N \l__fun_argument_tl
              }
            \c__fun_argtype_E_tl
              {
                \__fun_evaluate_all_and_put_argument:N \l__fun_argument_tl
              }
            \c__fun_argtype_m_tl
              {
                \__fun_evaluate_and_put_argument:N \l__fun_argument_tl
              }
            \c__fun_argtype_M_tl
              {
                \__fun_evaluate_and_put_argument:N \l__fun_argument_tl
              }
            \c__fun_argtype_n_tl
              {
                \__fun_arguments_gput:e { { \exp_not:V \l__fun_argument_tl } }
              }
            \c__fun_argtype_N_tl
              {
                \__fun_arguments_gput:e { \exp_not:V \l__fun_argument_tl }
              }
          }
      }
    \__fun_arguments_log:N #1
    \__fun_arguments_called:c { __fun_defined_ \cs_to_str:N #1 : w }
  }

\cs_new_protected:Npn \__fun_evaluate_all_and_put_argument:N #1
  {
    \__fun_eval_all:V #1
    \__fun_arguments_gput:e { { \exp_not:V \gResultTl } }
  }

\cs_new_protected:Npn \__fun_evaluate_and_put_argument:N #1
  {
    \cs_if_exist:cTF
      {
        __fun_defined_ \exp_last_unbraced:Ne \cs_to_str:N { \tl_head:N #1 } : w
      }
      {
        #1
        \__fun_arguments_gput:e { { \exp_not:V \gResultTl } }
      }
      {
        \__fun_arguments_gput:e { { \exp_not:V #1 } }
      }
  }

%% #1: argument number; #2: token lists
\cs_new_protected:Npn \__fun_one_argument_gset:nn #1 #2
  {
    \tl_gset:cn
      { g__fun_one_argument_ \int_use:N \g__fun_nesting_level_int _#1_tl } { #2 }
    %\__fun_one_argument_log:nn { #1 } { set }
  }

%% #1: argument number; #2: variable of token lists
\cs_new_protected:Npn \__fun_one_argument_get:nN #1 #2
  {
    \tl_set_eq:Nc
      #2 { g__fun_one_argument_ \int_use:N \g__fun_nesting_level_int _ #1 _tl }
    %\__fun_one_argument_log:nn { #1 } { get }
  }
\cs_generate_variant:Nn \__fun_one_argument_get:nN { eN }

%% #1: argument number; #2: get or set
\cs_new_protected:Npn \__fun_one_argument_log:nn #1 #2
  {
    \tl_log:e
      {
        #2 ~ level _ \int_use:N \g__fun_nesting_level_int _ arg _ #1 ~ = ~
        \exp_not:v
          { g__fun_one_argument_ \int_use:N \g__fun_nesting_level_int _#1_tl }
      }
  }

\int_new:c  { g__fun_argtype_index_ 1 _int }
\int_new:c  { g__fun_argtype_index_ 2 _int }
\int_new:c  { g__fun_argtype_index_ 3 _int }
\int_new:c  { g__fun_argtype_index_ 4 _int }
\int_new:c  { g__fun_argtype_index_ 5 _int }

\cs_new_protected:Npn \__fun_argtype_index_gzero:
  {
    \int_gzero_new:c
      { g__fun_argtype_index_ \int_use:N \g__fun_nesting_level_int _int }
  }

\cs_new_protected:Npn \__fun_argtype_index_gincr:
  {
    \int_gincr:c
      { g__fun_argtype_index_ \int_use:N \g__fun_nesting_level_int _int }
  }

\cs_new:Npn \__fun_argtype_index_use:
  {
    \int_use:c { g__fun_argtype_index_ \int_use:N \g__fun_nesting_level_int _int }
  }

\cs_new_protected:Npn \__fun_arguments_called:N #1
  {
    \exp_last_unbraced:Nv
      #1 { g__fun_arguments_ \int_use:N \g__fun_nesting_level_int _tl }
  }
\cs_generate_variant:Nn \__fun_arguments_called:N { c }

\cs_new_protected:Npn \__fun_arguments_gclear:
  {
    \tl_gclear:c { g__fun_arguments_ \int_use:N \g__fun_nesting_level_int _tl }
  }

\cs_new_protected:Npn \__fun_arguments_log:N #1
  {
    \__fun_tracing_log:e
    {
      [I] ~ \token_to_str:N #1
     \exp_not:v { g__fun_arguments_ \int_use:N \g__fun_nesting_level_int _tl }
    }
  }

\cs_new_protected:Npn \__fun_arguments_gput:n #1
  {
    \tl_gput_right:cn
      { g__fun_arguments_ \int_use:N \g__fun_nesting_level_int _tl } { #1 }
  }
\cs_generate_variant:Nn \__fun_arguments_gput:n { e }

%%% --------------------------------------------------------
%%> \subsection{Creating Some Useful Functions}
%%% --------------------------------------------------------

\prgNewFunction \prgSetEqFunction { N N }
  {
    \cs_set_eq:NN #1 #2
    \cs_set_eq:cc { __fun_defined_ \cs_to_str:N #1 : w }
      { __fun_defined_ \cs_to_str:N #2 : w }
  }

\prgNewFunction \prgDo {n} {#1}

\cs_set_eq:NN \prgBreak \prg_break:

\cs_set_eq:NN \prgBreakDo \prg_break:n

%%% --------------------------------------------------------
%%> \subsection{Return Values and Return Processors}
%%% --------------------------------------------------------

\cs_new_protected:Npn \__fun_put_result:n #1
  {
    \tl_gput_right:Nn \gResultTl { #1 }
  }
\cs_generate_variant:Nn \__fun_put_result:n { V, e, f, o }

\prgNewFunction \prgReturn { m }
  {
    \__fun_put_result:n { #1 }
  }
%% Obsolete function, will be removed in the future
%% We can not define it with \PrgSetEqFunction
\PrgNewFunction \Result { m }
  {
    \__fun_put_result:n { #1 }
  }

\int_new:N \l__fun_return_level_int

%% By default, the result is returned only if the function is not
%% nested in another function, but this behavior can be customized
\cs_new_protected:Npn \__fun_return_result:
  {
    \int_compare:nNnT { \g__fun_nesting_level_int } = { \l__fun_return_level_int }
      { \__fun_use_result: }
  }

\cs_new_protected:Npn \__fun_use_result_default:
  {
    \tl_use:N \gResultTl
  }

%% Set default return processor
\cs_new_protected:Npn \__fun_set_return_processor_default:
  {
    \int_set:Nn \l__fun_return_level_int {0}
    \cs_set_eq:NN \__fun_use_result: \__fun_use_result_default:
  }

\__fun_set_return_processor_default:

%% Set current nesting level and return processor
\cs_new_protected:Npn \__fun_set_return_processor:n #1
  {
    \int_set_eq:NN \l__fun_return_level_int \g__fun_nesting_level_int
    \cs_set_protected:Npn \__fun_use_result: { #1 }
  }

%% #1: return processor; #2: code to run
%% We do it inside groups for nesting processors to make correct results
\cs_new_protected:Npn \fun_run_return_processor:nn #1 #2
  {
    \group_begin:
    \__fun_set_return_processor:n {#1}
    #2
    \group_end:
  }

%%% --------------------------------------------------------
%%> \subsection{Evaluating Functions inside Arguments, I}
%%% --------------------------------------------------------

%% The function \__fun_eval_all:n is only used for arguments to be passed
%% to \int_eval:n, \fp_eval:n, \dim_eval:n, and similar functions.
%% It will not keep spaces, and will not distinguish between { and \bgroup.

\tl_new:N \l__fun_eval_result_tl

%% Evaluate all functions in #1 and replace them with their return values
\cs_new_protected:Npn \__fun_eval_all:n #1
  {
    \fun_run_return_processor:nn
      { \exp_last_unbraced:NV \__fun_eval_all_aux:n \gResultTl }
      {
        \tl_clear:N \l__fun_eval_result_tl
        \__fun_eval_all_aux:n #1 \q_stop
        \tl_gset_eq:NN \gResultTl \l__fun_eval_result_tl
      }
  }
\cs_generate_variant:Nn \__fun_eval_all:n { V }

\cs_new_protected:Npn \__fun_eval_all_aux:n #1
  {
    \tl_if_single_token:nTF {#1}
      {
        \token_if_eq_meaning:NNF #1 \q_stop
          {
            \bool_lazy_and:nnTF
              { \token_if_cs_p:N #1 }
              { \cs_if_exist_p:c { __fun_defined_ \cs_to_str:N #1 : w } }
              { #1 }
              {
                \tl_put_right:Nn \l__fun_eval_result_tl {#1}
                \__fun_eval_all_aux:n
              }
          }
      }
      {
        %% The braces enclosing a single token (such as {x}) are removed
        %% but I guess there is no harm inside \int_eval:n or \fp_eval:n
        \tl_put_right:Nn \l__fun_eval_result_tl { {#1} }
        \__fun_eval_all_aux:n
      }
  }

%%% --------------------------------------------------------
%%> \subsection{Evaluating Functions inside Arguments, II}
%%% --------------------------------------------------------

%% The function \evalWhole can be used in almost all use cases.
%% It will keep spaces, and will distinguish between { and \bgroup.

\prgNewFunction \evalWhole {n}
  {
    \__fun_eval_whole:n {#1}
  }

\tl_new:N \l__fun_eval_whole_tl
\bool_new:N \l__fun_eval_none_bool

%% Evaluate all functions in #1 and replace them with their return values
\cs_new_protected:Npn \__fun_eval_whole:n #1
  {
    \fun_run_return_processor:nn
      {
        \bool_if:NTF \l__fun_eval_none_bool
          {
            \tl_put_right:Nx \l__fun_eval_whole_tl
              { \exp_not:N \exp_not:n { \exp_not:V \gResultTl } }
            \bool_set_false:N \l__fun_eval_none_bool
            \__fun_eval_whole_aux:
          }
          { \exp_last_unbraced:NV \__fun_eval_whole_aux: \gResultTl }
      }
      {
        \tl_clear:N \l__fun_eval_whole_tl
        \__fun_eval_whole_aux: #1 \q_stop
        %\tl_log:N \l__fun_eval_whole_tl
        \tl_gset:Nx \gResultTl { \l__fun_eval_whole_tl }
      }
  }

\cs_new_protected:Npn \__fun_eval_whole_aux:
  {
    %% ##1: <tokens> which both o-expand and x-expand to the current <token>;
    %% ##2: <charcode>, a decimal number, −1 for a control sequence;
    %% ##3: <catcode>, a capital hexadecimal digit, 0 for a control sequence.
    \peek_analysis_map_inline:n
      {
        \int_compare:nNnTF {##2} = {-1} % control sequence
          {
            \exp_last_unbraced:No \token_if_eq_meaning:NNTF {##1} \q_stop
              { \peek_analysis_map_break: }
              {
                \cs_if_exist:cTF
                  { __fun_defined_ \exp_last_unbraced:No \cs_to_str:N {##1} : w }
                  {
                    \exp_last_unbraced:No \cs_if_eq:NNT {##1} \evalNone
                      { \bool_set_true:N \l__fun_eval_none_bool }
                    \peek_analysis_map_break:n
                      {
                        %% since ##1 is of the form "\exp_not:N \someFunc",
                        %% we need to remove \exp_not:N first before evaluating
                        \use:x {##1}
                      }
                  }
                  { \tl_put_right:Nn \l__fun_eval_whole_tl {##1} }
              }
          }
          { \tl_put_right:Nn \l__fun_eval_whole_tl {##1} }
      }
  }

%% The function \evalNone prevent the evaluation of its argument

\prgNewFunction \evalNone {n} { \tl_gset:Nn \gResultTl {#1} }

%%% --------------------------------------------------------
%%> \subsection{Printing Contents to the Input Stream}
%%% --------------------------------------------------------

\prgNewFunction \prgPrint { m }
  {
    \tl_log:n {running PrgPrint}
    \int_set_eq:NN \l__fun_return_level_int \g__fun_nesting_level_int
    #1
    \int_zero:N \l__fun_return_level_int
    \tl_gclear:N \gResultTl
  }

%%% --------------------------------------------------------
%%> \subsection{Filling Arguments into Inline Commands}
%%% --------------------------------------------------------

%% To make better tracing log, we want to expand the return value once,
%% but at the same time avoid evaluating the leading function in \gResultTl,
%% therefore we need to use \tl_set:Nn command instead of \tlSet function.

\prgNewFunction \prgRunOneArgCode { m n }
  {
    \cs_set:Npn \__fun_one_arg_cmd:n ##1 {#2}
    \exp_args:NNo \tl_set:Nn \gResultTl { \__fun_one_arg_cmd:n {#1} }
  }

\prgNewFunction \prgRunTwoArgCode { m m n }
  {
    \cs_set:Npn \__fun_two_arg_cmd:nn ##1 ##2 {#3}
    \exp_args:NNo \tl_set:Nn \gResultTl { \__fun_two_arg_cmd:nn {#1} {#2} }
  }

\prgNewFunction \prgRunThreeArgCode { m m m n }
  {
    \cs_set:Npn \__fun_three_arg_cmd:nnn ##1 ##2 ##3 {#4}
    \exp_args:NNo \tl_set:Nn \gResultTl
      { \__fun_three_arg_cmd:nnn {#1} {#2} {#3} }
  }

\prgNewFunction \prgRunFourArgCode { m m m m n }
  {
    \cs_set:Npn \__fun_four_arg_cmd:nnnn ##1 ##2 ##3 ##4 {#5}
    \exp_args:NNo \tl_set:Nn \gResultTl
      { \__fun_four_arg_cmd:nnnn {#1} {#2} {#3} {#4} }
  }

%%% --------------------------------------------------------
%%> \subsection{Checking for Local or Global Variables}
%%% --------------------------------------------------------

\str_new:N \l__fun_variable_name_str
\str_new:N \l__fun_variable_name_a_str
\str_new:N \l__fun_variable_name_b_str

\prg_new_protected_conditional:Npnn \__fun_if_global_variable:N #1 { TF }
  {
    \str_set:Ne \l__fun_variable_name_str { \cs_to_str:N #1 }
    \str_set:Ne \l__fun_variable_name_b_str
      { \str_item:Nn \l__fun_variable_name_str { 2 } }
    \str_if_eq:VeTF
      \l__fun_variable_name_b_str
      { \str_uppercase:f { \l__fun_variable_name_b_str } }
      {
        \str_set:Ne \l__fun_variable_name_a_str
          { \str_head:N \l__fun_variable_name_str }
        \str_case:VnF \l__fun_variable_name_a_str
          {
            { l } { \prg_return_false: }
            { g } { \prg_return_true: }
          }
          { \__fun_if_set_local: }
      }
      { \__fun_if_set_local: }
  }

\bool_new:N \g__fun_variable_local_bool

\cs_new:Npn \__fun_if_set_local:
  {
    \bool_if:NTF \g__fun_variable_local_bool
      {
        \bool_gset_false:N \g__fun_variable_local_bool
        \prg_return_false:
      }
      { \prg_return_true: }
  }

\prgNewFunction \prgLocal { }
  { \bool_gset_true:N \g__fun_variable_local_bool }

%% We must not put an assignment inside a group
\cs_new_protected:Npn \__fun_do_assignment:Nnn #1 #2 #3
  {
    \__fun_group_end:
    \__fun_if_global_variable:NTF #1 { #2 } { #3 }
    \__fun_group_begin:
  }

%%% --------------------------------------------------------
%%> \section{Interfaces for Argument Using (Use)}
%%% --------------------------------------------------------

\prgNewFunction \expName { m }
  {
    \exp_args:Nc \__fun_put_result:n { #1 }
  }

\prgNewFunction \expValue { M }
  {
    \__fun_put_result:V #1
  }

\prgNewFunction \expWhole { m }
  {
    \__fun_put_result:e { #1 }
  }

\prgNewFunction \expPartial { m }
  {
    \__fun_put_result:f { #1 }
  }

\prgNewFunction \expOnce { m }
  {
    \__fun_put_result:o { #1 }
  }

\cs_set_eq:NN \unExpand    \exp_not:n
\cs_set_eq:NN \noExpand    \exp_not:N
\cs_set_eq:NN \onlyName    \exp_not:c
\cs_set_eq:NN \onlyValue   \exp_not:V
\cs_set_eq:NN \onlyPartial \exp_not:f
\cs_set_eq:NN \onlyOnce    \exp_not:o

\prgNewFunction \useOne { n } { \prgReturn {#1} }

\prgNewFunction \gobbleOne { n } { }

\prgNewFunction \useGobble { n n } { \prgReturn {#1} }

\prgNewFunction \gobbleUse { n n } { \prgReturn {#2} }

%%% --------------------------------------------------------
%%> \section{Interfaces for Control Structures (Bool)}
%%% --------------------------------------------------------

\bool_const:Nn \cTrueBool { \c_true_bool }
\bool_const:Nn \cFalseBool { \c_false_bool }

\bool_new:N \lTmpaBool     \bool_new:N \lTmpbBool     \bool_new:N \lTmpcBool
\bool_new:N \lTmpiBool     \bool_new:N \lTmpjBool     \bool_new:N \lTmpkBool
\bool_new:N \l@FunTmpxBool \bool_new:N \l@FunTmpyBool \bool_new:N \l@FunTmpzBool

\bool_new:N \gTmpaBool     \bool_new:N \gTmpbBool     \bool_new:N \gTmpcBool
\bool_new:N \gTmpiBool     \bool_new:N \gTmpjBool     \bool_new:N \gTmpkBool
\bool_new:N \g@FunTmpxBool \bool_new:N \g@FunTmpyBool \bool_new:N \g@FunTmpzBool

\prgNewFunction \boolNew { M } { \bool_new:N #1 }

\prgNewFunction \boolConst { M e } { \bool_const:Nn #1 {#2} }

\prgNewFunction \boolSet { M e } {
  \__fun_do_assignment:Nnn #1
    { \bool_gset:Nn #1 {#2} } { \bool_set:Nn #1 {#2} }
}

\prgNewFunction \boolSetTrue { M }
  {
    \__fun_do_assignment:Nnn #1 { \bool_gset_true:N #1 } { \bool_set_true:N #1 }
  }

\prgNewFunction \boolSetFalse { M }
  {
    \__fun_do_assignment:Nnn #1 { \bool_gset_false:N #1 } { \bool_set_false:N #1 }
  }

\prgNewFunction \boolSetEq { M M }
  {
    \__fun_do_assignment:Nnn #1
      { \bool_gset_eq:NN #1 #2 } { \bool_set_eq:NN #1 #2 }
  }

\prgNewFunction \boolLog { e } { \bool_log:n {#1} }

\prgNewFunction \boolVarLog { M } { \bool_log:N #1 }

\prgNewFunction \boolShow { e } { \bool_show:n {#1} }

\prgNewFunction \boolVarShow { M } { \bool_show:N #1 }

\prgNewConditional \boolIfExist { M }
  {
    \bool_if_exist:NTF #1
      { \prgReturn { \cTrueBool } } { \prgReturn { \cFalseBool } }
  }

\prgNewConditional \boolVarIf { M } { \prgReturn {#1} }

\prgNewConditional \boolVarNot { M }
  {
    \bool_if:NTF #1
      { \prgReturn { \cFalseBool } } { \prgReturn { \cTrueBool } }
  }

\prgNewConditional \boolVarAnd { M M }
  {
    \bool_lazy_and:nnTF {#1} {#2}
      { \prgReturn { \cTrueBool } } { \prgReturn { \cFalseBool } }
  }

\prgNewConditional \boolVarOr { M M }
  {
    \bool_lazy_or:nnTF {#1} {#2}
      { \prgReturn { \cTrueBool } } { \prgReturn { \cFalseBool } }
  }

\prgNewConditional \boolVarXor { M M }
  {
    \bool_xor:nnTF {#1} {#2}
      { \prgReturn { \cTrueBool } } { \prgReturn { \cFalseBool } }
  }

\prgNewFunction \boolVarDoUntil { N n }
  {
    \bool_do_until:Nn #1 {#2}
  }

\prgNewFunction \boolVarDoWhile { N n }
  {
    \bool_do_while:Nn #1 {#2}
  }

\prgNewFunction \boolVarUntilDo { N n }
  {
    \bool_until_do:Nn #1 {#2}
  }

\prgNewFunction \boolVarWhileDo { N n }
  {
    \bool_while_do:Nn #1 {#2}
  }

%%% --------------------------------------------------------
%%> \section{Interfaces for Token Lists (Tl)}
%%% --------------------------------------------------------

\tl_set_eq:NN \cEmptyTl \c_empty_tl
\tl_set_eq:NN \cSpaceTl \c_space_tl
\tl_set_eq:NN \cNoValueTl \c_novalue_tl

\tl_new:N \lTmpaTl     \tl_new:N \lTmpbTl     \tl_new:N \lTmpcTl
\tl_new:N \lTmpiTl     \tl_new:N \lTmpjTl     \tl_new:N \lTmpkTl
\tl_new:N \l@FunTmpxTl \tl_new:N \l@FunTmpyTl \tl_new:N \l@FunTmpzTl

\tl_new:N \gTmpaTl     \tl_new:N \gTmpbTl     \tl_new:N \gTmpcTl
\tl_new:N \gTmpiTl     \tl_new:N \gTmpjTl     \tl_new:N \gTmpkTl
\tl_new:N \g@FunTmpxTl \tl_new:N \g@FunTmpyTl \tl_new:N \g@FunTmpzTl

\prgNewFunction \tlNew { M } { \tl_new:N #1 }

\prgNewFunction \tlLog { m } { \tl_log:n { #1 } }

\prgNewFunction \tlVarLog { M } { \tl_log:N #1 }

\prgNewFunction \tlShow { m } { \tl_show:n { #1 } }

\prgNewFunction \tlVarShow { M } { \tl_show:N #1 }

\prgNewFunction \tlUse { M } { \prgReturn { \expValue #1 } }

\prgNewFunction \tlToStr { m }
  { \expWhole { \tl_to_str:n { #1 } } }

\prgNewFunction \tlVarToStr { M }
  { \expWhole { \tl_to_str:N #1 } }

\prgNewFunction \tlConst { M m } { \tl_const:Nn #1 { #2 } }

\prgNewFunction \tlSet { M m }
  {
    \__fun_do_assignment:Nnn #1 { \tl_gset:Nn #1 {#2} } { \tl_set:Nn #1 {#2} }
  }

\prgNewFunction \tlSetEq { M M }
  {
    \__fun_do_assignment:Nnn #1 { \tl_gset_eq:NN #1 #2 } { \tl_set_eq:NN #1 #2 }
  }

\prgNewFunction \tlConcat { M M M }
  {
    \__fun_do_assignment:Nnn #1
      { \tl_gconcat:NNN #1 #2 #3 } { \tl_concat:NNN #1 #2 #3 }
  }

\prgNewFunction \tlClear { M }
  {
    \__fun_do_assignment:Nnn #1 { \tl_gclear:N #1 } { \tl_clear:N #1 }
  }

\prgNewFunction \tlClearNew { M }
  {
    \__fun_do_assignment:Nnn #1 { \tl_gclear_new:N #1 } { \tl_clear_new:N #1 }
  }

\prgNewFunction \tlPutLeft { M m }
  {
    \__fun_do_assignment:Nnn #1
      { \tl_gput_left:Nn #1 {#2} } { \tl_put_left:Nn #1 {#2} }
  }

\prgNewFunction \tlPutRight { M m }
  {
    \__fun_do_assignment:Nnn #1
      { \tl_gput_right:Nn #1 {#2} } { \tl_put_right:Nn #1 {#2} }
  }

\prgNewFunction \tlVarReplaceOnce { M m m }
  {
    \__fun_do_assignment:Nnn #1
      { \tl_greplace_once:Nnn #1 {#2} {#3} } { \tl_replace_once:Nnn #1 {#2} {#3} }
  }

\prgNewFunction \tlVarReplaceAll { M m m }
  {
    \__fun_do_assignment:Nnn #1
      { \tl_greplace_all:Nnn #1 {#2} {#3} } { \tl_replace_all:Nnn #1 {#2} {#3} }
  }

\prgNewFunction \tlVarRemoveOnce { M m }
  {
    \__fun_do_assignment:Nnn #1
      { \tl_gremove_once:Nn #1 {#2} } { \tl_remove_once:Nn #1 {#2} }
  }

\prgNewFunction \tlVarRemoveAll { M m }
  {
    \__fun_do_assignment:Nnn #1
      { \tl_gremove_all:Nn #1 {#2} } { \tl_remove_all:Nn #1 {#2} }
  }

\prgNewFunction \tlTrimSpaces { m }
  { \expWhole { \tl_trim_spaces:n { #1 } } }

\prgNewFunction \tlVarTrimSpaces { M }
  {
    \__fun_do_assignment:Nnn #1
      { \tl_gtrim_spaces:N #1 } { \tl_trim_spaces:N #1 }
  }

\prgNewFunction \tlCount { m }
  { \expWhole { \tl_count:n { #1 } } }

\prgNewFunction \tlVarCount { M }
  { \expWhole { \tl_count:N #1 } }

\prgNewFunction \tlHead { m }
  { \expWhole { \tl_head:n { #1 } } }

\prgNewFunction \tlVarHead { M }
  { \expWhole { \tl_head:N #1 } }

\prgNewFunction \tlTail { m }
  { \expWhole { \tl_tail:n { #1 } } }

\prgNewFunction \tlVarTail { M }
  { \expWhole { \tl_tail:N #1 } }

\prgNewFunction \tlItem { m m }
  { \expWhole { \tl_item:nn {#1} {#2} } }

\prgNewFunction \tlVarItem { M m }
  { \expWhole { \tl_item:Nn #1 {#2} } }

\prgNewFunction \tlRandItem { m }
  { \expWhole { \tl_rand_item:n {#1} } }

\prgNewFunction \tlVarRandItem { M }
  { \expWhole { \tl_rand_item:N #1 } }

\prgNewFunction \tlVarCase { M m }
  { \tl_case:Nn {#1} {#2} }
\prgNewFunction \tlVarCaseT { M m n }
  { \tl_case:NnT {#1} {#2} {#3} }
\prgNewFunction \tlVarCaseF { M m n }
  { \tl_case:NnF {#1} {#2} {#3} }
\prgNewFunction \tlVarCaseTF { M m n n }
  { \tl_case:NnTF {#1} {#2} {#3} {#4} }

\prgNewFunction \tlMapInline { m n }
  {
    \tl_map_inline:nn {#1} {#2}
  }

\prgNewFunction \tlVarMapInline { M n }
  {
    \tl_map_inline:Nn #1 {#2}
  }

\prgNewFunction \tlMapVariable { m M n }
  {
    \tl_map_variable:nNn {#1} #2 {#3}
  }

\prgNewFunction \tlVarMapVariable { M M n }
  {
    \tl_map_variable:NNn #1 #2 {#3}
  }

\prgNewConditional \tlIfExist { M }
  {
    \tl_if_exist:NTF #1
      { \prgReturn { \cTrueBool } }  { \prgReturn { \cFalseBool } }
  }

\prgNewConditional \tlIfEmpty { m }
  {
    \tl_if_empty:nTF {#1}
      { \prgReturn { \cTrueBool } }  { \prgReturn { \cFalseBool } }
  }

\prgNewConditional \tlVarIfEmpty { M }
  {
    \tl_if_empty:NTF #1
      { \prgReturn { \cTrueBool } }  { \prgReturn { \cFalseBool } }
  }

\prgNewConditional \tlIfBlank { m }
  {
    \tl_if_blank:nTF {#1}
      { \prgReturn { \cTrueBool } }  { \prgReturn { \cFalseBool } }
  }

\prgNewConditional \tlIfEq { m m }
  {
    \tl_if_eq:nnTF {#1} {#2}
      { \prgReturn { \cTrueBool } } { \prgReturn { \cFalseBool } }
  }

\prgNewConditional \tlVarIfEq { M M }
  {
    \tl_if_eq:NNTF #1 #2
      { \prgReturn { \cTrueBool } } { \prgReturn { \cFalseBool } }
  }

\prgNewConditional \tlIfIn { m m }
  {
    \tl_if_in:nnTF {#1} {#2}
      { \prgReturn { \cTrueBool } } { \prgReturn { \cFalseBool } }
  }

\prgNewConditional \tlVarIfIn { M m }
  {
    \tl_if_in:NnTF #1 {#2}
      { \prgReturn { \cTrueBool } } { \prgReturn { \cFalseBool } }
  }

\prgNewConditional \tlIfSingle { m }
  {
    \tl_if_single:nTF {#1}
      { \prgReturn { \cTrueBool } } { \prgReturn { \cFalseBool } }
  }

\prgNewConditional \tlVarIfSingle { M }
  {
    \tl_if_single:NTF #1
      { \prgReturn { \cTrueBool } } { \prgReturn { \cFalseBool } }
  }

%%% --------------------------------------------------------
%%> \section{Interfaces for Strings (Str)}
%%% --------------------------------------------------------

\str_set_eq:NN \cAmpersandStr  \c_ampersand_str
\str_set_eq:NN \cAttignStr     \c_atsign_str
\str_set_eq:NN \cBackslashStr  \c_backslash_str
\str_set_eq:NN \cLeftBraceStr  \c_left_brace_str
\str_set_eq:NN \cRightBraceStr \c_right_brace_str
\str_set_eq:NN \cCircumflexStr \c_circumflex_str
\str_set_eq:NN \cColonStr      \c_colon_str
\str_set_eq:NN \cDollarStr     \c_dollar_str
\str_set_eq:NN \cHashStr       \c_hash_str
\str_set_eq:NN \cPercentStr    \c_percent_str
\str_set_eq:NN \cTildeStr      \c_tilde_str
\str_set_eq:NN \cUnderscoreStr \c_underscore_str
\str_set_eq:NN \cZeroStr       \c_zero_str

\str_new:N \lTmpaStr     \str_new:N \lTmpbStr     \str_new:N \lTmpcStr
\str_new:N \lTmpiStr     \str_new:N \lTmpjStr     \str_new:N \lTmpkStr
\str_new:N \l@FunTmpxStr \str_new:N \l@FunTmpyStr \str_new:N \l@FunTmpzStr

\str_new:N \gTmpaStr     \str_new:N \gTmpbStr     \str_new:N \gTmpcStr
\str_new:N \gTmpiStr     \str_new:N \gTmpjStr     \str_new:N \gTmpkStr
\str_new:N \g@FunTmpxStr \str_new:N \g@FunTmpyStr \str_new:N \g@FunTmpzStr

\prgNewFunction \strNew { M } { \str_new:N #1 }

\prgNewFunction \strLog { m } { \str_log:n { #1 } }

\prgNewFunction \strVarLog { M } { \str_log:N #1 }

\prgNewFunction \strShow { m } { \str_show:n { #1 } }

\prgNewFunction \strVarShow { M } { \str_show:N #1 }

\prgNewFunction \strUse { M } { \prgReturn { \expValue #1 } }

\prgNewFunction \strConst { M m } { \str_const:Nn #1 {#2} }

\prgNewFunction \strSet { M m }
  {
    \__fun_do_assignment:Nnn #1 { \str_gset:Nn #1 {#2} } { \str_set:Nn #1 {#2} }
  }

\prgNewFunction \strSetEq { M M }
  {
    \__fun_do_assignment:Nnn #1
      { \str_gset_eq:NN #1 #2 } { \str_set_eq:NN #1 #2 }
  }

\prgNewFunction \strConcat { M M M }
  {
    \__fun_do_assignment:Nnn #1
      { \str_gconcat:NNN #1 #2 #3 } { \str_concat:NNN #1 #2 #3 }
  }

\prgNewFunction \strClear { M }
  {
    \__fun_do_assignment:Nnn #1 { \str_gclear:N #1 } { \str_clear:N #1 }
  }

\prgNewFunction \strClearNew { M }
  {
    \__fun_do_assignment:Nnn #1 { \str_gclear_new:N #1 } { \str_clear_new:N #1 }
  }

\prgNewFunction \strPutLeft { M m }
  {
    \__fun_do_assignment:Nnn #1
      { \str_gput_left:Nn #1 {#2} } { \str_put_left:Nn #1 {#2} }
  }

\prgNewFunction \strPutRight { M m }
  {
    \__fun_do_assignment:Nnn #1
      { \str_gput_right:Nn #1 {#2} } { \str_put_right:Nn #1 {#2} }
  }

\prgNewFunction \strVarReplaceOnce { M m m }
  {
    \__fun_do_assignment:Nnn #1
      { \str_greplace_once:Nnn #1 {#2} {#3} }
      { \str_replace_once:Nnn #1 {#2} {#3} }
  }

\prgNewFunction \strVarReplaceAll { M m m }
  {
    \__fun_do_assignment:Nnn #1
      { \str_greplace_all:Nnn #1 {#2} {#3} }
      { \str_replace_all:Nnn #1 {#2} {#3} }
  }

\prgNewFunction \strVarRemoveOnce { M m }
  {
    \__fun_do_assignment:Nnn #1
      { \str_gremove_once:Nn #1 {#2} } { \str_remove_once:Nn #1 {#2} }
  }

\prgNewFunction \strVarRemoveAll { M m }
  {
    \__fun_do_assignment:Nnn #1
      { \str_gremove_all:Nn #1 {#2} } { \str_remove_all:Nn #1 {#2} }
  }

\prgNewFunction \strCount { m } { \expWhole { \str_count:n { #1 } } }

\prgNewFunction \strVarCount { M } { \expWhole { \str_count:N #1 } }

\prgNewFunction \strHead { m } { \expWhole { \str_head:n { #1 } } }

\prgNewFunction \strVarHead { M } { \expWhole { \str_head:N #1 } }

\prgNewFunction \strTail { m } { \expWhole { \str_tail:n { #1 } } }

\prgNewFunction \strVarTail { M } { \expWhole { \str_tail:N #1 } }

\prgNewFunction \strItem { m m } { \expWhole { \str_item:nn {#1} {#2} } }

\prgNewFunction \strVarItem { M m } { \expWhole { \str_item:Nn #1 {#2} } }

\prgNewFunction \strCase { m m } { \str_case:nn {#1} {#2} }
\prgNewFunction \strCaseT { m m n } { \str_case:nnT {#1} {#2} {#3} }
\prgNewFunction \strCaseF { m m n } { \str_case:nnF {#1} {#2} {#3} }
\prgNewFunction \strCaseTF { m m n n } { \str_case:nnTF {#1} {#2} {#3} {#4} }

\prgNewFunction \strMapInline { m n } { \str_map_inline:nn {#1} {#2} }

\prgNewFunction \strVarMapInline { M n } { \str_map_inline:Nn #1 {#2} }

\prgNewFunction \strMapVariable { m M n } { \str_map_variable:nNn {#1} #2 {#3} }

\prgNewFunction \strVarMapVariable { M M n } { \str_map_variable:NNn #1 #2 {#3} }

\prgNewConditional \strIfExist { M }
  {
    \str_if_exist:NTF #1
      { \prgReturn { \cTrueBool } }  { \prgReturn { \cFalseBool } }
  }

\prgNewConditional \strVarIfEmpty { M }
  {
    \str_if_empty:NTF #1
      { \prgReturn { \cTrueBool } } { \prgReturn { \cFalseBool } }
  }

\prgNewConditional \strIfEq { m m }
  {
    \str_if_eq:nnTF {#1} {#2}
     { \prgReturn { \cTrueBool } } { \prgReturn { \cFalseBool } }
  }

\prgNewConditional \strVarIfEq { M M }
  {
    \str_if_eq:NNTF #1 #2
      { \prgReturn { \cTrueBool } } { \prgReturn { \cFalseBool } }
  }

\prgNewConditional \strIfIn { m m }
  {
    \str_if_in:nnTF {#1} {#2}
      { \prgReturn { \cTrueBool } } { \prgReturn { \cFalseBool } }
  }

\prgNewConditional \strVarIfIn { M m }
  {
    \str_if_in:NnTF #1 {#2}
      { \prgReturn { \cTrueBool } } { \prgReturn { \cFalseBool } }
  }

\prgNewConditional \strCompare { m N m }
  {
    \str_compare:nNnTF {#1} #2 {#3}
      { \prgReturn { \cTrueBool } }
      { \prgReturn { \cFalseBool } }
  }

%%% --------------------------------------------------------
%%> \section{Interfaces for Integers (Int)}
%%% --------------------------------------------------------

\cs_set_eq:NN \cZeroInt        \c_zero_int
\cs_set_eq:NN \cOneInt         \c_one_int
\cs_set_eq:NN \cMaxInt         \c_max_int
\cs_set_eq:NN \cMaxRegisterInt \c_max_register_int
\cs_set_eq:NN \cMaxCharInt     \c_max_char_in

\int_new:N \lTmpaInt     \int_new:N \lTmpbInt     \int_new:N \lTmpcInt
\int_new:N \lTmpiInt     \int_new:N \lTmpjInt     \int_new:N \lTmpkInt
\int_new:N \l@FunTmpxInt \int_new:N \l@FunTmpyInt \int_new:N \l@FunTmpzInt

\int_new:N \gTmpaInt     \int_new:N \gTmpbInt     \int_new:N \gTmpcInt
\int_new:N \gTmpiInt     \int_new:N \gTmpjInt     \int_new:N \gTmpkInt
\int_new:N \g@FunTmpxInt \int_new:N \g@FunTmpyInt \int_new:N \g@FunTmpzInt

\prgNewFunction \intEval { e } { \expWhole { \int_eval:n {#1} } }

\prgNewFunction \intMathAdd { e e } { \expWhole { \int_eval:n { (#1) + (#2) } } }

\prgNewFunction \intMathSub { e e } { \expWhole { \int_eval:n { (#1) - (#2) } } }

\prgNewFunction \intMathMult { e e } { \expWhole { \int_eval:n { (#1) * (#2) } } }

\prgNewFunction \intMathDiv { e e } { \expWhole { \int_div_round:nn {#1} {#2} } }

\prgNewFunction \intMathDivTruncate { e e }
  {
    \expWhole { \int_div_truncate:nn {#1} {#2} }
  }

\prgNewFunction \intMathSign { e } { \expWhole { \int_sign:n {#1} } }

\prgNewFunction \intMathAbs { e } { \expWhole { \int_abs:n {#1} } }

\prgNewFunction \intMathMax { e e } { \expWhole { \int_max:nn {#1} {#2} } }

\prgNewFunction \intMathMin { e e } { \expWhole { \int_min:nn {#1} {#2} } }

\prgNewFunction \intMathMod { e e } { \expWhole { \int_mod:nn {#1} {#2} } }

\prgNewFunction \intMathRand { e e } { \expWhole { \int_rand:nn {#1} {#2} } }

\prgNewFunction \intNew { M } { \int_new:N #1 }

\prgNewFunction \intConst { M e } { \int_const:Nn #1 { #2 } }

\prgNewFunction \intLog { e } { \int_log:n { #1 } }

\prgNewFunction \intVarLog { M } { \int_log:N #1 }

\prgNewFunction \intShow { e } { \int_show:n { #1 } }

\prgNewFunction \intVarShow { M } { \int_show:N #1 }

\prgNewFunction \intUse { M } { \prgReturn { \expValue #1 } }

\prgNewFunction \intSet { M e }
  {
    \__fun_do_assignment:Nnn #1 { \int_gset:Nn #1 {#2} } { \int_set:Nn #1 {#2} }
  }

\prgNewFunction \intZero { M }
  {
    \__fun_do_assignment:Nnn #1 { \int_gzero:N #1 } { \int_zero:N #1 }
  }

\prgNewFunction \intZeroNew { M }
  {
    \__fun_do_assignment:Nnn #1 { \int_gzero_new:N #1 } { \int_zero_new:N #1 }
  }

\prgNewFunction \intSetEq { M M }
  {
    \__fun_do_assignment:Nnn #1
      { \int_gset_eq:NN #1 #2 } { \int_set_eq:NN #1 #2 }
  }

\prgNewFunction \intIncr { M }
  {
    \__fun_do_assignment:Nnn #1 { \int_gincr:N #1 } { \int_incr:N #1 }
  }

\prgNewFunction \intDecr { M }
  {
    \__fun_do_assignment:Nnn #1 { \int_gdecr:N #1 } { \int_decr:N #1 }
  }

\prgNewFunction \intAdd { M e }
  {
    \__fun_do_assignment:Nnn #1 { \int_gadd:Nn #1 {#2} } { \int_add:Nn #1 {#2} }
  }

\prgNewFunction \intSub { M e }
  {
    \__fun_do_assignment:Nnn #1 { \int_gsub:Nn #1 {#2} } { \int_sub:Nn #1 {#2} }
  }

%% Command \prg_replicate:nn yields its result after two expansion steps
\prgNewFunction \intReplicate { e m }
  {
    \exp_args:NNo \exp_args:No \prgReturn { \prg_replicate:nn {#1} {#2} }
  }

\prgNewFunction \intStepInline { e e e n }
  {
    \int_step_inline:nnnn {#1} {#2} {#3} {#4}
  }

\prgNewFunction \intStepOneInline { e e n }
  {
    \int_step_inline:nnn {#1} {#2} {#3}
  }

\prgNewFunction \intStepVariable { e e e M n }
  {
    \int_step_variable:nnnNn {#1} {#2} {#3} #4 {#5}
  }

\prgNewFunction \intStepOneVariable { e e M n }
  {
    \int_step_variable:nnNn {#1} {#2} #3 {#4}
  }

\prgNewConditional \intIfExist { M }
  {
    \int_if_exist:NTF #1
      { \prgReturn { \cTrueBool } } { \prgReturn { \cFalseBool } }
  }

\prgNewConditional \intIfOdd { e }
  {
    \int_if_odd:nTF { #1 }
      { \prgReturn { \cTrueBool } } { \prgReturn { \cFalseBool } }
  }

\prgNewConditional \intIfEven { e }
  {
    \int_if_even:nTF { #1 }
      { \prgReturn { \cTrueBool } } { \prgReturn { \cFalseBool } }
  }

\prgNewConditional \intCompare { e N e }
  {
    \int_compare:nNnTF {#1} #2 {#3}
      { \prgReturn { \cTrueBool } }
      { \prgReturn { \cFalseBool } }
  }

\prgNewFunction \intCase { e m } { \int_case:nn {#1} {#2} }
\prgNewFunction \intCaseT { e m n } { \int_case:nnT {#1} {#2} {#3} }
\prgNewFunction \intCaseF { e m n } { \int_case:nnF {#1} {#2} {#3} }
\prgNewFunction \intCaseTF { e m n n } { \int_case:nnTF {#1} {#2} {#3} {#4} }

%%% --------------------------------------------------------
%%> \section{Interfaces for Floating Point Numbers (Fp)}
%%% --------------------------------------------------------

\fp_set_eq:NN \cZeroFp      \c_zero_fp
\fp_set_eq:NN \cMinusZeroFp \c_minus_zero_fp
\fp_set_eq:NN \cOneFp       \c_one_fp
\fp_set_eq:NN \cInfFp       \c_inf_fp
\fp_set_eq:NN \cMinusInfFp  \c_minus_inf_fp
\fp_set_eq:NN \cEFp         \c_e_fp
\fp_set_eq:NN \cPiFp        \c_pi_fp
\fp_set_eq:NN \cOneDegreeFp \c_one_degree_fp

\fp_new:N \lTmpaFp     \fp_new:N \lTmpbFp     \fp_new:N \lTmpcFp
\fp_new:N \lTmpiFp     \fp_new:N \lTmpjFp     \fp_new:N \lTmpkFp
\fp_new:N \l@FunTmpxFp \fp_new:N \l@FunTmpyFp \fp_new:N \l@FunTmpzFp

\fp_new:N \gTmpaFp     \fp_new:N \gTmpbFp     \fp_new:N \gTmpcFp
\fp_new:N \gTmpiFp     \fp_new:N \gTmpjFp     \fp_new:N \gTmpkFp
\fp_new:N \g@FunTmpxFp \fp_new:N \g@FunTmpyFp \fp_new:N \g@FunTmpzFp

\prgNewFunction \fpEval { e } { \expWhole { \fp_eval:n {#1} } }

\prgNewFunction \fpMathAdd { e e } { \expWhole { \fp_eval:n { (#1) + (#2) } } }

\prgNewFunction \fpMathSub { e e } { \expWhole { \fp_eval:n { (#1) - (#2) } } }

\prgNewFunction \fpMathMult { e e } { \expWhole { \fp_eval:n { (#1) * (#2) } } }

\prgNewFunction \fpMathDiv { e e } { \expWhole { \fp_eval:n { (#1) / (#2) } } }

\prgNewFunction \fpMathSign { e } { \expWhole { \fp_sign:n {#1} } }

\prgNewFunction \fpMathAbs { e } { \expWhole { \fp_abs:n {#1} } }

\prgNewFunction \fpMathMax { e e } { \expWhole { \fp_max:nn {#1} {#2} } }

\prgNewFunction \fpMathMin { e e } { \expWhole { \fp_min:nn {#1} {#2} } }

\prgNewFunction \fpNew { M } { \fp_new:N #1 }

\prgNewFunction \fpConst { M e } { \fp_const:Nn #1 {#2} }

\prgNewFunction \fpUse { M } { \expWhole { \fp_use:N #1 } }

\prgNewFunction \fpLog { e } { \fp_log:n {#1} }

\prgNewFunction \fpVarLog { M } { \fp_log:N #1 }

\prgNewFunction \fpShow { e } { \fp_show:n {#1} }

\prgNewFunction \fpVarShow { M } { \fp_show:N #1 }

\prgNewFunction \fpSet { M e }
  {
    \__fun_do_assignment:Nnn #1 { \fp_gset:Nn #1 {#2} } { \fp_set:Nn #1 {#2} }
  }

\prgNewFunction \fpSetEq { M M }
  {
    \__fun_do_assignment:Nnn #1 { \fp_gset_eq:NN #1 #2 } { \fp_set_eq:NN #1 #2 }
  }

\prgNewFunction \fpZero { M }
  {
    \__fun_do_assignment:Nnn #1 { \fp_gzero:N #1 } { \fp_zero:N #1 }
  }

\prgNewFunction \fpZeroNew { M }
  {
    \__fun_do_assignment:Nnn #1 { \fp_gzero_new:N #1 } { \fp_zero_new:N #1 }
  }

\prgNewFunction \fpAdd { M e }
  {
    \__fun_do_assignment:Nnn #1 { \fp_gadd:Nn #1 {#2} } { \fp_add:Nn #1 {#2} }
  }

\prgNewFunction \fpSub { M e }
  {
    \__fun_do_assignment:Nnn #1 { \fp_gsub:Nn #1 {#2} } { \fp_sub:Nn #1 {#2} }
  }

\prgNewFunction \fpStepInline { e e e n }
  {
    \fp_step_inline:nnnn {#1} {#2} {#3} {#4}
  }

\prgNewFunction \fpStepVariable { e e e M n }
  {
    \fp_step_variable:nnnNn {#1} {#2} {#3} #4 {#5}
  }

\prgNewConditional \fpIfExist { M }
  {
    \fp_if_exist:NTF #1
      { \prgReturn { \cTrueBool } } { \prgReturn { \cFalseBool } }
  }

\prgNewConditional \fpCompare { e N e }
  {
    \fp_compare:nNnTF {#1} #2 {#3}
      { \prgReturn { \cTrueBool } }
      { \prgReturn { \cFalseBool } }
  }

%%% --------------------------------------------------------
%%> \section{Interfaces for Dimensions (Dim)}
%%% --------------------------------------------------------

\cs_set_eq:NN \cMaxDim  \c_max_dim
\cs_set_eq:NN \cZeroDim \c_zero_dim

\dim_new:N \lTmpaDim     \dim_new:N \lTmpbDim     \dim_new:N \lTmpcDim
\dim_new:N \lTmpiDim     \dim_new:N \lTmpjDim     \dim_new:N \lTmpkDim
\dim_new:N \l@FunTmpxDim \dim_new:N \l@FunTmpyDim \dim_new:N \l@FunTmpzDim

\dim_new:N \gTmpaDim     \dim_new:N \gTmpbDim     \dim_new:N \gTmpcDim
\dim_new:N \gTmpiDim     \dim_new:N \gTmpjDim     \dim_new:N \gTmpkDim
\dim_new:N \g@FunTmpxDim \dim_new:N \g@FunTmpyDim \dim_new:N \g@FunTmpzDim

\prgNewFunction \dimEval { m }
  {
    \prgReturn { \expWhole { \dim_eval:n { #1 } } }
  }

\prgNewFunction \dimMathAdd { m m }
  {
    \dim_set:Nn \l@FunTmpxDim { \dim_eval:n { (#1) + (#2) } }
    \prgReturn { \expValue \l@FunTmpxDim }
  }

\prgNewFunction \dimMathSub { m m }
  {
    \dim_set:Nn \l@FunTmpxDim { \dim_eval:n { (#1) - (#2) } }
    \prgReturn { \expValue \l@FunTmpxDim }
  }

\prgNewFunction \dimMathSign { m }
  {
    \prgReturn { \expWhole { \dim_sign:n { #1 } } }
  }

\prgNewFunction \dimMathAbs { m }
  {
    \prgReturn { \expWhole { \dim_abs:n { #1 } } }
  }

\prgNewFunction \dimMathMax { m m }
  {
    \prgReturn { \expWhole { \dim_max:nn { #1 } { #2 } } }
  }

\prgNewFunction \dimMathMin { m m }
  {
    \prgReturn { \expWhole { \dim_min:nn { #1 } { #2 } } }
  }

\prgNewFunction \dimMathRatio { m m }
  {
    \prgReturn { \expWhole { \dim_ratio:nn { #1 } { #2 } } }
  }

\prgNewFunction \dimNew { M } { \dim_new:N #1 }

\prgNewFunction \dimConst { M m } { \dim_const:Nn #1 {#2} }

\prgNewFunction \dimUse { M } { \prgReturn { \expValue #1 } }

\prgNewFunction \dimLog { m } { \dim_log:n { #1 } }

\prgNewFunction \dimVarLog { M } { \dim_log:N #1 }

\prgNewFunction \dimShow { m } { \dim_show:n { #1 } }

\prgNewFunction \dimVarShow { M } { \dim_show:N #1 }

\prgNewFunction \dimSet { M m }
  {
    \__fun_do_assignment:Nnn #1 { \dim_gset:Nn #1 {#2} } { \dim_set:Nn #1 {#2} }
  }

\prgNewFunction \dimSetEq { M M }
  {
    \__fun_do_assignment:Nnn #1
      { \dim_gset_eq:NN #1 #2 } { \dim_set_eq:NN #1 #2 }
  }

\prgNewFunction \dimZero { M }
  {
    \__fun_do_assignment:Nnn #1 { \dim_gzero:N #1 } { \dim_zero:N #1 }
  }

\prgNewFunction \dimZeroNew { M }
  {
    \__fun_do_assignment:Nnn #1 { \dim_gzero_new:N #1 } { \dim_zero_new:N #1 }
  }

\prgNewFunction \dimAdd { M m }
  {
    \__fun_do_assignment:Nnn #1 { \dim_gadd:Nn #1 {#2} } { \dim_add:Nn #1 {#2} }
  }

\prgNewFunction \dimSub { M m }
  {
    \__fun_do_assignment:Nnn #1 { \dim_gsub:Nn #1 {#2} } { \dim_sub:Nn #1 {#2} }
  }

\prgNewFunction \dimStepInline { m m m n }
  {
    \dim_step_inline:nnnn { #1 } { #2 } { #3 } { #4 }
  }

\prgNewFunction \dimStepVariable { m m m M n }
  {
    \dim_step_variable:nnnNn { #1 } { #2 } { #3 } #4 { #5 }
  }

\prgNewConditional \dimIfExist { M }
  {
    \dim_if_exist:NTF #1
      { \prgReturn { \cTrueBool } } { \prgReturn { \cFalseBool } }
  }

\prgNewConditional \dimCompare { m N m }
  {
    \dim_compare:nNnTF {#1} #2 {#3}
      { \prgReturn { \cTrueBool } } { \prgReturn { \cFalseBool } }
  }

\prgNewFunction \dimCase { m m }
  { \dim_case:nn {#1} {#2} }
\prgNewFunction \dimCaseT { m m n }
  { \dim_case:nnT {#1} {#2} {#3} }
\prgNewFunction \dimCaseF { m m n }
  { \dim_case:nnF {#1} {#2} {#3} }
\prgNewFunction \dimCaseTF { m m n n }
  { \dim_case:nnTF {#1} {#2} {#3} {#4} }

%%% --------------------------------------------------------
%%> \section{Interfaces for Sorting Functions (Sort)}
%%% --------------------------------------------------------

\cs_set_eq:NN \sortReturnSame \sort_return_same:
\cs_set_eq:NN \sortReturnSwapped \sort_return_swapped:

%%% --------------------------------------------------------
%%> \section{Interfaces for Comma Separated Lists (Clist)}
%%% --------------------------------------------------------

\clist_new:N \lTmpaClist \clist_new:N \lTmpbClist \clist_new:N \lTmpcClist
\clist_new:N \lTmpiClist \clist_new:N \lTmpjClist \clist_new:N \lTmpkClist

\clist_new:N \gTmpaClist \clist_new:N \gTmpbClist \clist_new:N \gTmpcClist
\clist_new:N \gTmpiClist \clist_new:N \gTmpjClist \clist_new:N \gTmpkClist

\clist_new:N \l@FunTmpxClist \clist_new:N \g@FunTmpxClist
\clist_new:N \l@FunTmpyClist \clist_new:N \g@FunTmpyClist
\clist_new:N \l@FunTmpzClist \clist_new:N \g@FunTmpzClist

\clist_set_eq:NN \cEmptyClist \c_empty_clist

\prgNewFunction \clistNew { M } { \clist_new:N #1 }

\prgNewFunction \clistLog { m } { \clist_log:n { #1 } }

\prgNewFunction \clistVarLog { M } { \clist_log:N #1 }

\prgNewFunction \clistShow { m } { \clist_show:n { #1 } }

\prgNewFunction \clistVarShow { M } { \clist_show:N #1 }

\prgNewFunction \clistVarJoin { M m }
  {
    \expWhole { \clist_use:Nn #1 { #2 } }
  }

\prgNewFunction \clistVarJoinExtended { M m m m }
  {
    \expWhole { \clist_use:Nnnn #1 { #2 } { #3 } { #4 } }
  }

\prgNewFunction \clistJoin { m m }
  {
    \expWhole { \clist_use:nn { #1 } { #2 } }
  }

\prgNewFunction \clistJoinExtended { m m m m }
  {
    \expWhole { \clist_use:nnnn { #1 } { #2 } { #3 } { #4 } }
  }

\prgNewFunction \clistConst { M m }
  { \clist_const:Nn #1 { #2 } }

\prgNewFunction \clistSet { M m }
  {
    \__fun_do_assignment:Nnn #1
      { \clist_gset:Nn #1 {#2} } { \clist_set:Nn #1 {#2} }
  }

\prgNewFunction \clistSetEq { M M }
  {
    \__fun_do_assignment:Nnn #1
      { \clist_gset_eq:NN #1 #2 } { \clist_set_eq:NN #1 #2 }
  }

\prgNewFunction \clistSetFromSeq { M M }
  {
    \__fun_do_assignment:Nnn #1
      { \clist_gset_from_seq:NN #1 #2 } { \clist_set_from_seq:NN #1 #2 }
  }

\prgNewFunction \clistConcat { M M M }
  {
    \__fun_do_assignment:Nnn #1
      { \clist_gconcat:NNN #1 #2 #3 } { \clist_concat:NNN #1 #2 #3 }
  }

\prgNewFunction \clistClear { M }
  {
    \__fun_do_assignment:Nnn #1 { \clist_gclear:N #1 } { \clist_clear:N #1 }
  }

\prgNewFunction \clistClearNew { M }
  {
    \__fun_do_assignment:Nnn #1
      { \clist_gclear_new:N #1 } { \clist_clear_new:N #1 }
  }

\prgNewFunction \clistPutLeft { M m }
  {
    \__fun_do_assignment:Nnn #1
      { \clist_gput_left:Nn #1 {#2} } { \clist_put_left:Nn #1 {#2} }
  }

\prgNewFunction \clistPutRight { M m }
  {
    \__fun_do_assignment:Nnn #1
      { \clist_gput_right:Nn #1 {#2} } { \clist_put_right:Nn #1 {#2} }
  }

\prgNewFunction \clistVarRemoveDuplicates { M }
  {
    \__fun_do_assignment:Nnn #1
      { \clist_gremove_duplicates:N #1 } { \clist_remove_duplicates:N #1 }
  }

\prgNewFunction \clistVarRemoveAll { M m }
  {
    \__fun_do_assignment:Nnn #1
      { \clist_gremove_all:Nn #1 {#2} } { \clist_remove_all:Nn #1 {#2} }
  }

\prgNewFunction \clistVarReverse { M }
  {
    \__fun_do_assignment:Nnn #1 { \clist_greverse:N #1 } { \clist_reverse:N #1 }
  }

\prgNewFunction \clistVarSort { M m }
  {
    \__fun_do_assignment:Nnn #1
      { \clist_gsort:Nn #1 {#2} } { \clist_sort:Nn #1 {#2} }
  }

\prgNewFunction \clistCount { m }
  { \expWhole { \clist_count:n { #1 } } }

\prgNewFunction \clistVarCount { M }
  { \expWhole { \clist_count:N #1 } }

\prgNewFunction \clistGet { M M }
  {
    \clist_get:NN #1 #2
    \__fun_quark_upgrade_no_value:N #2
  }
\prgNewFunction \clistGetT { M M n } { \clist_get:NNT #1 #2 {#3} }
\prgNewFunction \clistGetF { M M n } { \clist_get:NNF #1 #2 {#3} }
\prgNewFunction \clistGetTF { M M n n } { \clist_get:NNTF #1 #2 {#3} {#4} }

\prgNewFunction \clistPop { M M }
  {
    \__fun_do_assignment:Nnn #1
      { \clist_gpop:NN #1 #2 } { \clist_pop:NN #1 #2 }
    \__fun_quark_upgrade_no_value:N #2
  }
\prgNewFunction \clistPopT { M M n }
  {
    \__fun_do_assignment:Nnn #1
      { \clist_gpop:NNT #1 #2 {#3} } { \clist_pop:NNT #1 #2 {#3} }
  }
\prgNewFunction \clistPopF { M M n }
  {
    \__fun_do_assignment:Nnn #1
      { \clist_gpop:NNF #1 #2 {#3} } { \clist_pop:NNF #1 #2 {#3} }
  }
\prgNewFunction \clistPopTF { M M n n }
  {
    \__fun_do_assignment:Nnn #1
      { \clist_gpop:NNTF #1 #2 {#3} {#4} } { \clist_pop:NNTF #1 #2 {#3} {#4} }
  }

\prgNewFunction \clistPush { M m }
  {
    \__fun_do_assignment:Nnn #1
      { \clist_gpush:Nn #1 {#2} } { \clist_push:Nn #1 {#2} }
  }

\prgNewFunction \clistItem { m m }
  { \expWhole { \clist_item:nn {#1} {#2} } }

\prgNewFunction \clistVarItem { M m }
  { \expWhole { \clist_item:Nn #1 {#2} } }

\prgNewFunction \clistRandItem { m }
  { \expWhole { \clist_rand_item:n {#1} } }

\prgNewFunction \clistVarRandItem { M }
  { \expWhole { \clist_rand_item:N #1 } }

\prgNewFunction \clistMapInline { m n }
  {
    \clist_map_inline:nn {#1} {#2}
  }

\prgNewFunction \clistVarMapInline { M n }
  {
    \clist_map_inline:Nn #1 {#2}
  }

\prgNewFunction \clistMapVariable { m M n }
  {
    \clist_map_variable:nNn {#1} #2 {#3}
  }

\prgNewFunction \clistVarMapVariable { M M n }
  {
    \clist_map_variable:NNn #1 #2 {#3}
  }

\cs_set_eq:NN \clistMapBreak \clist_map_break:

\prgNewConditional \clistIfExist { M }
  {
    \clist_if_exist:NTF #1
      { \prgReturn { \cTrueBool } }  { \prgReturn { \cFalseBool } }
  }

\prgNewConditional \clistIfEmpty { m }
  {
    \clist_if_empty:nTF {#1}
      { \prgReturn { \cTrueBool } }  { \prgReturn { \cFalseBool } }
  }

\prgNewConditional \clistVarIfEmpty { M }
  {
    \clist_if_empty:NTF #1
      { \prgReturn { \cTrueBool } }  { \prgReturn { \cFalseBool } }
  }

\prgNewConditional \clistIfIn { m m }
  {
    \clist_if_in:nnTF {#1} {#2}
      { \prgReturn { \cTrueBool } }  { \prgReturn { \cFalseBool } }
  }

\prgNewConditional \clistVarIfIn { M m }
  {
    \clist_if_in:NnTF #1 {#2}
      { \prgReturn { \cTrueBool } }  { \prgReturn { \cFalseBool } }
  }

%%% --------------------------------------------------------
%%> \section{Interfaces for Sequences and Stacks (Seq)}
%%% --------------------------------------------------------

\seq_new:N \lTmpaSeq     \seq_new:N \lTmpbSeq     \seq_new:N \lTmpcSeq
\seq_new:N \lTmpiSeq     \seq_new:N \lTmpjSeq     \seq_new:N \lTmpkSeq
\seq_new:N \l@FunTmpxSeq \seq_new:N \l@FunTmpySeq \seq_new:N \l@FunTmpzSeq

\seq_new:N \gTmpaSeq     \seq_new:N \gTmpbSeq     \seq_new:N \gTmpcSeq
\seq_new:N \gTmpiSeq     \seq_new:N \gTmpjSeq     \seq_new:N \gTmpkSeq
\seq_new:N \g@FunTmpxSeq \seq_new:N \g@FunTmpySeq \seq_new:N \g@FunTmpzSeq

\seq_set_eq:NN \cEmptySeq \c_empty_seq

\prgNewFunction \seqNew { M } { \seq_new:N #1 }

\prgNewFunction \seqVarLog { M } { \seq_log:N #1 }

\prgNewFunction \seqVarShow { M } { \seq_show:N #1 }

\prgNewFunction \seqVarJoin { M m }
  {
    \expWhole { \seq_use:Nn #1 { #2 } }
  }

\prgNewFunction \seqVarJoinExtended { M m m m }
  {
    \expWhole { \seq_use:Nnnn #1 { #2 } { #3 } { #4 } }
  }

\prgNewFunction \seqJoin { m m }
  {
    \expWhole { \seq_use:nn { #1 } { #2 } }
  }

\prgNewFunction \seqJoinExtended { m m m m }
  {
    \expWhole { \seq_use:nnnn { #1 } { #2 } { #3 } { #4 } }
  }

\prgNewFunction \seqConstFromClist { M m }
  { \seq_const_from_clist:Nn #1 { #2 } }

\prgNewFunction \seqSetFromClist { M m }
  {
    \__fun_do_assignment:Nnn #1
      { \seq_gset_from_clist:Nn #1 {#2} } { \seq_set_from_clist:Nn #1 {#2} }
  }

\prgNewFunction \seqSetEq { M M }
  {
    \__fun_do_assignment:Nnn #1
      { \seq_gset_eq:NN #1 #2 } { \seq_set_eq:NN #1 #2 }
  }

\prgNewFunction \seqSetSplit { M m m }
  {
    \__fun_do_assignment:Nnn #1
      { \seq_gset_split:Nnn #1 {#2} {#3} } { \seq_set_split:Nnn #1 {#2} {#3} }
  }

\prgNewFunction \seqConcat { M M M }
  {
    \__fun_do_assignment:Nnn #1
      { \seq_gconcat:NNN #1 #2 #3 } { \seq_concat:NNN #1 #2 #3 }
  }

\prgNewFunction \seqClear { M }
  {
    \__fun_do_assignment:Nnn #1 { \seq_gclear:N #1 } { \seq_clear:N #1 }
  }

\prgNewFunction \seqClearNew { M }
  {
    \__fun_do_assignment:Nnn #1 { \seq_gclear_new:N #1 } { \seq_clear_new:N #1 }
  }

\prgNewFunction \seqPutLeft { M m }
  {
    \__fun_do_assignment:Nnn #1
      { \seq_gput_left:Nn #1 {#2} } { \seq_put_left:Nn #1 {#2} }
  }

\prgNewFunction \seqPutRight { M m }
  {
    \__fun_do_assignment:Nnn #1
      { \seq_gput_right:Nn #1 {#2} } { \seq_put_right:Nn #1 {#2} }
  }

\prgNewFunction \seqVarRemoveDuplicates { M }
  {
    \__fun_do_assignment:Nnn #1
      { \seq_gremove_duplicates:N #1 } { \seq_remove_duplicates:N #1 }
  }

\prgNewFunction \seqVarRemoveAll { M m }
  {
    \__fun_do_assignment:Nnn #1
      { \seq_gremove_all:Nn #1 {#2} } { \seq_remove_all:Nn #1 {#2} }
  }

\prgNewFunction \seqVarReverse { M }
  {
    \__fun_do_assignment:Nnn #1 { \seq_greverse:N #1 } { \seq_reverse:N #1 }
  }

\prgNewFunction \seqVarSort { M m }
  {
    \__fun_do_assignment:Nnn #1
      { \seq_gsort:Nn #1 {#2} } { \seq_sort:Nn #1 {#2} }
  }

\prgNewFunction \seqVarCount { M }
  { \expWhole { \seq_count:N #1 } }

\prgNewFunction \seqGet { M M }
  {
    \seq_get:NN #1 #2
    \__fun_quark_upgrade_no_value:N #2
  }
\prgNewFunction \seqGetT { M M n }
  { \seq_get:NNT #1 #2 {#3} }
\prgNewFunction \seqGetF { M M n }
  { \seq_get:NNF #1 #2 {#3} }
\prgNewFunction \seqGetTF { M M n n }
  { \seq_get:NNTF #1 #2 {#3} {#4} }

\prgNewFunction \seqPop { M M }
  {
    \__fun_do_assignment:Nnn #1
      { \seq_gpop:NN #1 #2 } { \seq_pop:NN #1 #2 }
    \__fun_quark_upgrade_no_value:N #2
  }
\prgNewFunction \seqPopT { M M n }
  {
    \__fun_do_assignment:Nnn #1
      { \seq_gpop:NNT #1 #2 {#3} } { \seq_pop:NNT #1 #2 {#3} }
  }
\prgNewFunction \seqPopF { M M n }
  {
    \__fun_do_assignment:Nnn #1
      { \seq_gpop:NNF #1 #2 {#3} } { \seq_pop:NNF #1 #2 {#3} }
  }
\prgNewFunction \seqPopTF { M M n n }
  {
    \__fun_do_assignment:Nnn #1
      { \seq_gpop:NNTF #1 #2 {#3} {#4} } { \seq_pop:NNTF #1 #2 {#3} {#4} }
  }

\prgNewFunction \seqPush { M m }
  {
    \__fun_do_assignment:Nnn #1
      { \seq_gpush:Nn #1 {#2} } { \seq_push:Nn #1 {#2} }
  }

\prgNewFunction \seqGetLeft { M M }
  {
    \seq_get_left:NN #1 #2
    \__fun_quark_upgrade_no_value:N #2
  }
\prgNewFunction \seqGetLeftT { M M n }
  { \seq_get_left:NNT #1 #2 {#3} }
\prgNewFunction \seqGetLeftF { M M n }
  { \seq_get_left:NNF #1 #2 {#3} }
\prgNewFunction \seqGetLeftTF { M M n n }
  { \seq_get_left:NNTF #1 #2 {#3} {#4} }

\prgNewFunction \seqGetRight { M M }
  {
    \seq_get_right:NN #1 #2
    \__fun_quark_upgrade_no_value:N #2
  }
\prgNewFunction \seqGetRightT { M M n }
  { \seq_get_right:NNT #1 #2 {#3} }
\prgNewFunction \seqGetRightF { M M n }
  { \seq_get_right:NNF #1 #2 {#3} }
\prgNewFunction \seqGetRightTF { M M n n }
  { \seq_get_right:NNTF #1 #2 {#3} {#4} }

\prgNewFunction \seqPopLeft { M M }
  {
    \__fun_do_assignment:Nnn #1
      { \seq_gpop_left:NN #1 #2 } { \seq_pop_left:NN #1 #2 }
    \__fun_quark_upgrade_no_value:N #2
  }
\prgNewFunction \seqPopLeftT { M M n }
  {
    \__fun_do_assignment:Nnn #1
      { \seq_gpop_left:NNT #1 #2 {#3} } { \seq_pop_left:NNT #1 #2 {#3} }
  }
\prgNewFunction \seqPopLeftF { M M n }
  {
    \__fun_do_assignment:Nnn #1
      { \seq_gpop_left:NNF #1 #2 {#3} } { \seq_pop_left:NNF #1 #2 {#3} }
  }
\prgNewFunction \seqPopLeftTF { M M n n }
  {
    \__fun_do_assignment:Nnn #1
      { \seq_gpop_left:NNTF #1 #2 {#3} {#4} }
      { \seq_pop_left:NNTF #1 #2 {#3} {#4} }
  }

\prgNewFunction \seqPopRight { M M }
  {
    \__fun_do_assignment:Nnn #1
      { \seq_gpop_right:NN #1 #2 } { \seq_pop_right:NN #1 #2 }
    \__fun_quark_upgrade_no_value:N #2
  }
\prgNewFunction \seqPopRightT { M M n }
  {
    \__fun_do_assignment:Nnn #1
      { \seq_gpop_right:NNT #1 #2 {#3} } { \seq_pop_right:NNT #1 #2 {#3} }
  }
\prgNewFunction \seqPopRightF { M M n }
  {
    \__fun_do_assignment:Nnn #1
      { \seq_gpop_right:NNF #1 #2 {#3} } { \seq_pop_right:NNF #1 #2 {#3} }
  }
\prgNewFunction \seqPopRightTF { M M n n }
  {
    \__fun_do_assignment:Nnn #1
      { \seq_gpop_right:NNTF #1 #2 {#3} {#4} }
      { \seq_pop_right:NNTF #1 #2 {#3} {#4} }
  }

\prgNewFunction \seqVarItem { M m }
  { \expWhole { \seq_item:Nn #1 {#2} } }

\prgNewFunction \seqVarRandItem { M }
  { \expWhole { \seq_rand_item:N #1 } }

\prgNewFunction \seqVarMapInline { M n }
  {
    \seq_map_inline:Nn #1 {#2}
  }

\prgNewFunction \seqVarMapVariable { M M n }
  {
    \seq_map_variable:NNn #1 #2 {#3}
  }

\cs_set_eq:NN \seqMapBreak \seq_map_break:

\prgNewConditional \seqIfExist { M }
  {
    \seq_if_exist:NTF #1
      { \prgReturn { \cTrueBool } }  { \prgReturn { \cFalseBool } }
  }

\prgNewConditional \seqVarIfEmpty { M }
  {
    \seq_if_empty:NTF #1
      { \prgReturn { \cTrueBool } }  { \prgReturn { \cFalseBool } }
  }

\prgNewConditional \seqVarIfIn { M m }
  {
    \seq_if_in:NnTF #1 {#2}
      { \prgReturn { \cTrueBool } }  { \prgReturn { \cFalseBool } }
  }

%%% --------------------------------------------------------
%%> \section{Interfaces for Property Lists (Prop)}
%%% --------------------------------------------------------

\prop_new:N \lTmpaProp     \prop_new:N \lTmpbProp     \prop_new:N \lTmpcProp
\prop_new:N \lTmpiProp     \prop_new:N \lTmpjProp     \prop_new:N \lTmpkProp
\prop_new:N \l@FunTmpxProp \prop_new:N \l@FunTmpyProp \prop_new:N \l@FunTmpzProp

\prop_new:N \gTmpaProp     \prop_new:N \gTmpbProp     \prop_new:N \gTmpcProp
\prop_new:N \gTmpiProp     \prop_new:N \gTmpjProp     \prop_new:N \gTmpkProp
\prop_new:N \g@FunTmpxProp \prop_new:N \g@FunTmpyProp \prop_new:N \g@FunTmpzProp

\prop_const_from_keyval:Nn \cEmptyProp {}

\prgNewFunction \propNew { M } { \prop_new:N #1 }

\prgNewFunction \propVarLog { M } { \prop_log:N #1 }

\prgNewFunction \propVarShow { M } { \prop_show:N #1 }

\prgNewFunction \propConstFromKeyval { M m }
  { \prop_const_from_keyval:Nn #1 { #2 } }

\prgNewFunction \propSetFromKeyval { M m }
  {
    \__fun_do_assignment:Nnn #1
      { \prop_gset_from_keyval:Nn #1 {#2} } { \prop_set_from_keyval:Nn #1 {#2} }
  }

\prgNewFunction \propSetEq { M M }
  {
    \__fun_do_assignment:Nnn #1
      { \prop_gset_eq:NN #1 #2 } { \prop_set_eq:NN #1 #2 }
  }

\prgNewFunction \propClear { M }
  {
    \__fun_do_assignment:Nnn #1 { \prop_gclear:N #1 } { \prop_clear:N #1 }
  }

\prgNewFunction \propClearNew { M }
  {
    \__fun_do_assignment:Nnn #1 { \prop_gclear_new:N #1 } { \prop_clear_new:N #1 }
  }

\prgNewFunction \propConcat { M M M }
  {
    \__fun_do_assignment:Nnn #1
      { \prop_gconcat:NNN #1 #2 #3 } { \prop_concat:NNN #1 #2 #3 }
  }

\prgNewFunction \propPut { M m m }
  {
    \__fun_do_assignment:Nnn #1
      { \prop_gput:Nnn #1 {#2} {#3} } { \prop_put:Nnn #1 {#2} {#3} }
  }

\prgNewFunction \propPutIfNew { M m m }
  {
    \__fun_do_assignment:Nnn #1
      { \prop_gput_if_new:Nnn #1 {#2} {#3} } { \prop_put_if_new:Nnn #1 {#2} {#3} }
  }

\prgNewFunction \propPutFromKeyval { M m }
  {
    \__fun_do_assignment:Nnn #1
      { \prop_gput_from_keyval:Nn #1 {#2} } { \prop_put_from_keyval:Nn #1 {#2} }
  }

\prgNewFunction \propVarRemove { M m }
  {
    \__fun_do_assignment:Nnn #1
      { \prop_gremove:Nn #1 {#2} } { \prop_remove:Nn #1 {#2} }
  }

\prgNewFunction \propVarCount { M } { \expWhole { \prop_count:N #1 } }

\prgNewFunction \propVarItem { M m } { \expWhole { \prop_item:Nn #1 {#2} } }

\prgNewFunction \propToKeyval { M } { \expWhole { \prop_to_keyval:N #1 } }

\prgNewFunction \propGet { M m M }
  {
    \prop_get:NnN #1 {#2} #3
    \__fun_quark_upgrade_no_value:N #3
  }
\prgNewFunction \propGetT { M m M n } { \prop_get:NnNT #1 {#2} #3 {#4} }
\prgNewFunction \propGetF { M m M n } { \prop_get:NnNF #1 {#2} #3 {#4} }
\prgNewFunction \propGetTF { M m M n n } { \prop_get:NnNTF #1 {#2} #3 {#4} {#5} }

\prgNewFunction \propPop { M m M }
  {
    \__fun_do_assignment:Nnn #1
      { \prop_gpop:NnN #1 {#2} #3 } { \prop_pop:NnN #1 {#2} #3 }
    \__fun_quark_upgrade_no_value:N #3
  }
\prgNewFunction \propPopT { M m M n }
  {
    \__fun_do_assignment:Nnn #1
      { \prop_gpop:NnNT #1 {#2} #3 {#4} } { \prop_pop:NnNT #1 {#2} #3 {#4} }
  }
\prgNewFunction \propPopF { M m M n }
  {
    \__fun_do_assignment:Nnn #1
      { \prop_gpop:NnNF #1 {#2} #3 {#4} } { \prop_pop:NnNF #1 {#2} #3 {#4} }
  }
\prgNewFunction \propPopTF { M m M n n }
  {
    \__fun_do_assignment:Nnn #1
      { \prop_gpop:NnNTF #1 {#2} #3 {#4} {#5} }
      { \prop_pop:NnNTF #1 {#2} #3 {#4} {#5} }
  }

\prgNewFunction \propVarMapInline { M n } { \prop_map_inline:Nn #1 {#2} }

\cs_set_eq:NN \propMapBreak \prop_map_break:

\prgNewConditional \propIfExist { M }
  {
    \prop_if_exist:NTF #1
      { \prgReturn { \cTrueBool } }  { \prgReturn { \cFalseBool } }
  }

\prgNewConditional \propVarIfEmpty { M }
  {
    \prop_if_empty:NTF #1
      { \prgReturn { \cTrueBool } }  { \prgReturn { \cFalseBool } }
  }

\prgNewConditional \propVarIfIn { M m }
  {
    \prop_if_in:NnTF #1 {#2}
      { \prgReturn { \cTrueBool } }  { \prgReturn { \cFalseBool } }
  }

%%% --------------------------------------------------------
%%> \section{Interfaces for Regular Expressions (Regex)}
%%% --------------------------------------------------------

\regex_new:N \lTmpaRegex  \regex_new:N \lTmpbRegex  \regex_new:N \lTmpcRegex
\regex_new:N \lTmpiRegex  \regex_new:N \lTmpjRegex  \regex_new:N \lTmpkRegex

\regex_new:N \gTmpaRegex  \regex_new:N \gTmpbRegex  \regex_new:N \gTmpcRegex
\regex_new:N \gTmpiRegex  \regex_new:N \gTmpjRegex  \regex_new:N \gTmpkRegex

\regex_new:N \l@FunTmpxRegex  \regex_new:N \g@FunTmpxRegex
\regex_new:N \l@FunTmpyRegex  \regex_new:N \g@FunTmpyRegex
\regex_new:N \l@FunTmpzRegex  \regex_new:N \g@FunTmpzRegex

\prgNewFunction \regexNew { M } { \regex_new:N #1 }

\prgNewFunction \regexSet { M m }
  {
    \__fun_do_assignment:Nnn #1
     { \regex_gset:Nn #1 {#2} } { \regex_set:Nn #1 {#2} }
  }

\prgNewFunction \regexConst { M m } { \regex_const:Nn #1 {#2} }

\prgNewFunction \regexLog { m } { \regex_log:n {#1} }

\prgNewFunction \regexVarLog { M } { \regex_log:N #1 }

\prgNewFunction \regexShow { m } { \regex_show:n {#1} }

\prgNewFunction \regexVarShow { M } { \regex_show:N #1 }

\prgNewConditional \regexMatch { m m }
  {
    \regex_match:nnTF {#1} {#2}
      { \prgReturn { \cTrueBool } }  { \prgReturn { \cFalseBool } }
  }

\prgNewConditional \regexVarMatch { M m }
  {
    \regex_match:NnTF #1 {#2}
      { \prgReturn { \cTrueBool } }  { \prgReturn { \cFalseBool } }
  }

\prgNewFunction \regexCount { m m M } { \regex_count:nnN {#1} {#2} #3 }

\prgNewFunction \regexVarCount { M m M } { \regex_count:NnN #1 {#2} #3 }

\prgNewFunction \regexMatchCase { m m }
  {
    \regex_match_case:nn {#1} {#2}
  }
\prgNewFunction \regexMatchCaseT { m m n }
  {
    \regex_match_case:nnT {#1} {#2} {#3}
  }
\prgNewFunction \regexMatchCaseF { m m n }
  {
    \regex_match_case:nnF {#1} {#2} {#3}
  }
\prgNewFunction \regexMatchCaseTF { m m n n }
  {
    \regex_match_case:nnTF {#1} {#2} {#3} {#4}
  }

\prgNewFunction \regexExtractOnce { m m M }
  {
    \regex_extract_once:nnN {#1} {#2} #3
  }
\prgNewFunction \regexExtractOnceT { m m M n }
  {
    \regex_extract_once:nnNT {#1} {#2} #3 {#4}
  }
\prgNewFunction \regexExtractOnceF { m m M n }
  {
    \regex_extract_once:nnNF {#1} {#2} #3 {#4}
  }
\prgNewFunction \regexExtractOnceTF { m m M n n }
  {
    \regex_extract_once:nnNTF {#1} {#2} #3 {#4} {#5}
  }

\prgNewFunction \regexVarExtractOnce { M m M }
  {
    \regex_extract_once:NnN #1 {#2} #3
  }
\prgNewFunction \regexVarExtractOnceT { M m M n }
  {
    \regex_extract_once:NnNT #1 {#2} #3 {#4}
  }
\prgNewFunction \regexVarExtractOnceF { M m M n }
  {
    \regex_extract_once:NnNF #1 {#2} #3 {#4}
  }
\prgNewFunction \regexVarExtractOnceTF { M m M n n }
  {
    \regex_extract_once:NnNTF #1 {#2} #3 {#4} {#5}
  }

\prgNewFunction \regexExtractAll { m m M }
  {
    \regex_extract_all:nnN {#1} {#2} #3
  }
\prgNewFunction \regexExtractAllT { m m M n }
  {
    \regex_extract_all:nnNT {#1} {#2} #3 {#4}
  }
\prgNewFunction \regexExtractAllF { m m M n }
  {
    \regex_extract_all:nnNF {#1} {#2} #3 {#4}
  }
\prgNewFunction \regexExtractAllTF { m m M n n }
  {
    \regex_extract_all:nnNTF {#1} {#2} #3 {#4} {#5}
  }

\prgNewFunction \regexVarExtractAll { M m M }
  {
    \regex_extract_all:NnN #1 {#2} #3
  }
\prgNewFunction \regexVarExtractAllT { M m M n }
  {
    \regex_extract_all:NnNT #1 {#2} #3 {#4}
  }
\prgNewFunction \regexVarExtractAllF { M m M n }
  {
    \regex_extract_all:NnNF #1 {#2} #3 {#4}
  }
\prgNewFunction \regexVarExtractAllTF { M m M n n }
  {
    \regex_extract_all:NnNTF #1 {#2} #3 {#4} {#5}
  }

\prgNewFunction \regexSplit { m m M }
  {
    \regex_split:nnN {#1} {#2} #3
  }
\prgNewFunction \regexSplitT { m m M n }
  {
    \regex_split:nnNT {#1} {#2} #3 {#4}
  }
\prgNewFunction \regexSplitF { m m M n }
  {
    \regex_split:nnNF {#1} {#2} #3 {#4}
  }
\prgNewFunction \regexSplitTF { m m M n n }
  {
    \regex_split:nnNTF {#1} {#2} #3 {#4} {#5}
  }

\prgNewFunction \regexVarSplit { M m M }
  {
    \regex_split:NnN #1 {#2} #3
  }
\prgNewFunction \regexVarSplitT { M m M n }
  {
    \regex_split:NnNT #1 {#2} #3 {#4}
  }
\prgNewFunction \regexVarSplitF { M m M n }
  {
    \regex_split:NnNF #1 {#2} #3 {#4}
  }
\prgNewFunction \regexVarSplitTF { M m M n n }
  {
    \regex_split:NnNTF #1 {#2} #3 {#4} {#5}
  }

\prgNewFunction \regexReplaceOnce { m m M }
  {
    \regex_replace_once:nnN {#1} {#2} #3
  }
\prgNewFunction \regexReplaceOnceT { m m M n }
  {
    \regex_replace_once:nnNT {#1} {#2} #3 {#4}
  }
\prgNewFunction \regexReplaceOnceF { m m M n }
  {
    \regex_replace_once:nnNF {#1} {#2} #3 {#4}
  }
\prgNewFunction \regexReplaceOnceTF { m m M n n }
  {
    \regex_replace_once:nnNTF {#1} {#2} #3 {#4} {#5}
  }

\prgNewFunction \regexVarReplaceOnce { M m M }
  {
    \regex_replace_once:NnN #1 {#2} #3
  }
\prgNewFunction \regexVarReplaceOnceT { M m M n }
  {
    \regex_replace_once:NnNT #1 {#2} #3 {#4}
  }
\prgNewFunction \regexVarReplaceOnceF { M m M n }
  {
    \regex_replace_once:NnNF #1 {#2} #3 {#4}
  }
\prgNewFunction \regexVarReplaceOnceTF { M m M n n }
  {
    \regex_replace_once:NnNTF #1 {#2} #3 {#4} {#5}
  }

\prgNewFunction \regexReplaceAll { m m M }
  {
    \regex_replace_all:nnN {#1} {#2} #3
  }
\prgNewFunction \regexReplaceAllT { m m M n }
  {
    \regex_replace_all:nnNT {#1} {#2} #3 {#4}
  }
\prgNewFunction \regexReplaceAllF { m m M n }
  {
    \regex_replace_all:nnNF {#1} {#2} #3 {#4}
  }
\prgNewFunction \regexReplaceAllTF { m m M n n }
  {
    \regex_replace_all:nnNTF {#1} {#2} #3 {#4} {#5}
  }

\prgNewFunction \regexVarReplaceAll { M m M }
  {
    \regex_replace_all:NnN #1 {#2} #3
  }
\prgNewFunction \regexVarReplaceAllT { M m M n }
  {
    \regex_replace_all:NnNT #1 {#2} #3 {#4}
  }
\prgNewFunction \regexVarReplaceAllF { M m M n }
  {
    \regex_replace_all:NnNF #1 {#2} #3 {#4}
  }
\prgNewFunction \regexVarReplaceAllTF { M m M n n }
  {
    \regex_replace_all:NnNTF #1 {#2} #3 {#4} {#5}
  }

\prgNewFunction \regexReplaceCaseOnce { m M }
  {
    \regex_replace_case_once:nN {#1} #2
  }
\prgNewFunction \regexReplaceCaseOnceT { m M n }
  {
    \regex_replace_case_once:nN {#1} #2 {#3}
  }
\prgNewFunction \regexReplaceCaseOnceF { m M n }
  {
    \regex_replace_case_once:nN {#1} #2 {#3}
  }
\prgNewFunction \regexReplaceCaseOnceTF { m M n n }
  {
    \regex_replace_case_once:nN {#1} #2 {#3} {#4}
  }

\prgNewFunction \regexReplaceCaseAll { m M }
  {
    \regex_replace_case_all:nN {#1} #2
  }
\prgNewFunction \regexReplaceCaseAllT { m M n }
  {
    \regex_replace_case_all:nN {#1} #2 {#3}
  }
\prgNewFunction \regexReplaceCaseAllF { m M n }
  {
    \regex_replace_case_all:nN {#1} #2 {#3}
  }
\prgNewFunction \regexReplaceCaseAllTF { m M n n }
  {
    \regex_replace_case_all:nN {#1} #2 {#3} {#4}
  }

%%% --------------------------------------------------------
%%> \section{Interfaces for Token Manipulation (Token)}
%%% --------------------------------------------------------

\prgNewFunction \charLowercase { M } { \expWhole { \char_lowercase:N #1 } }

\prgNewFunction \charUppercase { M } { \expWhole { \char_uppercase:N #1 } }

\prgNewFunction \charTitlecase { M } { \expWhole { \char_titlecase:N #1 } }

\prgNewFunction \charFoldcase { M } { \expWhole { \char_foldcase:N #1 } }

\prgNewFunction \charStrLowercase { M } { \expWhole { \char_str_lowercase:N #1 } }

\prgNewFunction \charStrUppercase { M } { \expWhole { \char_str_uppercase:N #1 } }

\prgNewFunction \charStrTitlecase { M } { \expWhole { \char_str_titlecase:N #1 } }

\prgNewFunction \charStrFoldcase { M } { \expWhole { \char_str_foldcase:N #1 } }

\prgNewFunction \charSetLccode { m m } { \char_set_lccode:nn {#1} {#2} }

\prgNewFunction \charValueLccode { m } { \expWhole { \char_value_lccode:n {#1} } }

\prgNewFunction \charSetUccode { m m } { \char_set_uccode:nn {#1} {#2} }

\prgNewFunction \charValueUccode { m } { \expWhole { \char_value_uccode:n {#1} } }

%%% --------------------------------------------------------
%%> \section{Interfaces for Text Processing (Text)}
%%% --------------------------------------------------------

\prgNewFunction \textExpand { m }
  {
    \expWhole { \text_expand:n {#1} }
  }

\prgNewFunction \textLowercase { m }
  {
    \expWhole { \text_lowercase:n {#1} }
  }

\prgNewFunction \textUppercase { m }
  {
    \expWhole { \text_uppercase:n {#1} }
  }

\prgNewFunction \textTitlecase { m }
  {
    \expWhole { \text_titlecase:n {#1} }
  }

\prgNewFunction \textTitlecaseFirst { m }
  {
    \expWhole { \text_titlecase_first:n {#1} }
  }

\prgNewFunction \textLangLowercase { m m }
  {
    \expWhole { \text_lowercase:nn {#1} {#2} }
  }

\prgNewFunction \textLangUppercase { m m }
  {
    \expWhole { \text_uppercase:nn {#1} {#2} }
  }

\prgNewFunction \textLangTitlecase { m m }
  {
    \expWhole { \text_titlecase:nn {#1} {#2} }
  }

\prgNewFunction \textLangTitlecaseFirst { m m }
  {
    \expWhole { \text_titlecase_first:nn {#1} {#2} }
  }

%%% --------------------------------------------------------
%%> \section{Interfaces for Files (File)}
%%% --------------------------------------------------------

\msg_new:nnn { functional } { file-not-found } { File ~ "#1" ~ not ~ found! }

\prgNewFunction \fileInput { m }
  {
    \file_get:nnN {#1} {} \l@FunTmpxTl
    \quark_if_no_value:NTF \l@FunTmpxTl
      { \msg_error:nnn { functional } { file-not-found } { #1 } }
      { \tlUse \l@FunTmpxTl }
  }

\prgNewFunction \fileIfExistInput { m }
  {
    \file_get:nnN {#1} {} \l@FunTmpxTl
    \quark_if_no_value:NF \l@FunTmpxTl { \tlUse \l@FunTmpxTl }
  }

\prgNewFunction \fileIfExistInputF { m n }
  {
    \file_get:nnN {#1} {} \l@FunTmpxTl
    \quark_if_no_value:NTF \l@FunTmpxTl { #2 } { \tlUse \l@FunTmpxTl }
  }

\cs_set_eq:NN \fileInputStop \file_input_stop:

\prgNewFunction \fileGet { m m M }
  {
    \file_get:nnN {#1} {#2} #3
    \__fun_quark_upgrade_no_value:N #3
  }

\prgNewFunction \fileGetT { m m M n }
  {
    \file_get:nnNT {#1} {#2} #3 {#4}
  }

\prgNewFunction \fileGetF { m m M n }
  {
    \file_get:nnNF {#1} {#2} #3 {#4}
  }

\prgNewFunction \fileGetTF { m m M n n }
  {
    \file_get:nnNTF {#1} {#2} #3 {#4} {#5}
  }

\prgNewConditional \fileIfExist { m }
  {
    \file_if_exist:nTF {#1}
      { \prgReturn { \cTrueBool } }  { \prgReturn { \cFalseBool } }
  }

%%% --------------------------------------------------------
%%> \section{Interfaces for Quarks (Quark)}
%%% --------------------------------------------------------

\quark_new:N \qNoValue

\cs_new_protected:Npn \__fun_quark_upgrade_no_value:N #1
  {
    \quark_if_no_value:NT #1 { \tl_set_eq:NN #1 \qNoValue }
  }

\prgNewConditional \quarkVarIfNoValue { M }
  {
    \tl_if_eq:NNTF \qNoValue #1
      { \prgReturn { \cTrueBool } }  { \prgReturn { \cFalseBool } }
  }

%%% --------------------------------------------------------
%%> \section{Interfaces to Legacy Concepts (Legacy)}
%%% --------------------------------------------------------

\prgNewConditional \legacyIf { m }
  {
    \legacy_if:nTF {#1}
      { \prgReturn { \cTrueBool } }  { \prgReturn { \cFalseBool } }
  }

\prgNewFunction \legacyIfSetTrue { m }
  {
    \__fun_do_assignment:Nnn \c@name
      { \legacy_if_gset_true:n {#1} } { \legacy_if_set_true:n {#1} }
  }

\prgNewFunction \legacyIfSetFalse { m }
  {
    \__fun_do_assignment:Nnn \c@name
      { \legacy_if_gset_false:n {#1} } { \legacy_if_set_false:n {#1} }
  }

\prgNewFunction \legacyIfSet { m m }
  {
    \__fun_do_assignment:Nnn \c@name
      { \legacy_if_gset:nn {#1} {#2} } { \legacy_if_set:nn {#1} {#2} }
  }