Use of named arguments instead of numbers in LaTeX

Question

ConTeXt has a .mkvi file extension for modules (roughly similar to LaTeX packages) which allows to use named arguments like:

\def\foo[#parameters]#content{ #parameters ... #content ...}

instead of

\def\foo[#1]#2{#1 ... #2 ...}

Not really a difference, but it has an advantage that macros tend to be more readable. Are there any packages or functionalities which allow the same for LaTeX?

Answer 1

I wrote something like that some time ago to assist in another project of mine. Some internal macros started to have too many arguments and I was changing their order too often, so keeping track of the argument numbers was becoming a nuisance (and often lead to errors).

To solve that, I wrote the namedef package, that allows you to change from (an admittedly boring example):

\def\Say#1 to #2%
  {#1, #2!}

to

\named\def\Say#[greeting] to #[whom]%
  {#[greeting], #[whom]!}

The advantage I saw in this syntax is that if you decide to swap the order of #[greeting] and #[whom] in the parameter text, you don't have to change them in the replacement text—the advantage of semantics over syntax :-)

The code works by scanning the definition for #6[⟨name⟩], replacing them by numbers, and then handing the translated tokens for TeX to perform the definition.

The code is hosted at https://github.com/PhelypeOleinik/namedef. To build the .sty file, run tex namedef.ins, and to build the documentation, run pdflatex namedef.ins. The generated .sty file can be used in LaTeX with \usepackage{namedef}, or in other formats with \input namedef.sty.