Latex: \newcommand interpret # symbol problem - latex

Question

I defined a new command
\newcommand{\test}[1]{\href{https://github.com/microsoft/vscode/blob/main/package.json#1}{#1}}
When I use it as follows:
\test{#L4}
the url will be interpreted as:
https://github.com/microsoft/vscode/blob/main/package.json##L4
There is an extra # in the url, which is unexpected. What I really want is:
https://github.com/microsoft/vscode/blob/main/package.json#L4
which means line 4 of the package.json code
The easiest but no so elegant way to solve the problem is as follows.
\test{\#L4}
but what if other special characters like _ appear in the part of url I copy? It's boring to correct these meaningless grammar mistakes.
Is there any more elegant way to solve the problem? What I want is to copy plain text, which is part of url to the latex code and no extra efforts like adding \ escape character before # and other special characters are needed.

Answer 1

What I want is to copy plain text, which is part of url to the latex code and no extra efforts like adding \ escape character before # and other special characters are needed.
I am afraid it will require extra effort because # is used as a parameter for macros in LaTeX. You can play with redefining categories and when # is consumed, restore its original meaning.
I have another solution based on expl3 where I save the main address and create links with additional parts. See a small demo below
\documentclass{article}
\usepackage[colorlinks]{hyperref}
\usepackage[margin=1in]{geometry} % To fit long links without breaks
\ExplSyntaxOn
\str_new:N \l__xaddr_main_str
\str_new:N \l__xaddr_show_str
\cs_new:Npn \combine_addr:n #1 {
\str_set:Nn \l_tmpa_str {#1}
\str_concat:NNN \l__xaddr_show_str \l__xaddr_main_str \l_tmpa_str
}
\NewDocumentCommand\xsetmainaddr{v}{
\str_set:Nn \l__xaddr_main_str {#1}}
\NewDocumentCommand\xdisplay{v}{%
\str_if_empty:NF \l__xaddr_main_str {
\combine_addr:n {#1}
\str_use:N \l__xaddr_show_str
}}
\NewDocumentCommand\xhref{vv}{%
\str_if_empty:NF \l__xaddr_main_str {
\combine_addr:n {#1}
\href{\l__xaddr_show_str}{#2}
}}
\ExplSyntaxOff
\setlength\parindent{0pt} % To fit long links without breaks
\begin{document}
\xhref{#L4}{GitHub} % Nothing to display. The main address is not defined.
\xsetmainaddr{https://github.com/microsoft/vscode/blob/main/package.json}
\par\xdisplay{#L4} % Display the full address including #L4
\par\xdisplay{#something_else%20here} % all characters accepted
\par\xhref{#L4}{GitHub} % Generates link: <address>#L4
\bigskip
\xsetmainaddr{http://www.google.com} % New address
\par\xhref{}{Google} % Generates link
\end{document}