General ⇒ expl3 meta macro

[erwann]

I'd like to create a macro for creating external macros that conform to a template. Cld someone pls make a suggestion? Perhaps '\exp_args:Nc' somewhere?

Code: Select all

\documentclass{article}
\usepackage{xparse}

\ExplSyntaxOn

\cs_new:Npn
	\impl #1
		{
			(#1)
		}

\cs_new:Npn \metamacro #1 {
	\NewDocumentCommand {\cs:w #1 \cs_end: } 
%		{
			{ m }
			{
				\impl{#1}
			}
%		}
}

\metamacro{baz}

\ExplSyntaxOff

\begin{document}

\baz % Expected: (baz)

\end{document}

[cgnieder]

The first argument to \NewDocumentCommand can only be one command sequence token and not – like in your case – an instruction to build one. This means you have to build the command sequence token before passing it to \NewDocumentCommand.

Also you are not following expl3 guidelines and naming conventions. Here is a working suggestion:

Code: Select all

\documentclass{article}
\usepackage{xparse}
 
\ExplSyntaxOn
\cs_new:Npn \ewann_impl:n #1 { (#1) }
 
\cs_new_protected:Npn \ewann_metamacro:n #1
  {
    \exp_args:Nc \NewDocumentCommand {#1} {}
      { \ewann_impl:n {#1} }
  }

\NewDocumentCommand \metamacro {m}
  { \ewann_metamacro:n {#1} }
\ExplSyntaxOff
 
\begin{document}

\metamacro{baz}

\baz % Expected: (baz)
 
\end{document}