how do I test for a unique string with multiple possibilities?

Question

I'm writing a macro that takes a string and it returns an href based on that string. The string could have 150 different values. My question is how to write this in an efficient way. Using pdflatex.

Here's what I've got right now, shortened to two conditions for explanation:

\documentclass{article}
\usepackage{hyperref}
\newcommand{\myref}[1]{%
   \ifnum\pdfstrcmp{#1}{aaa}=0%
      \href{example.com/aaa}{my aaa link}
   \fi
   \ifnum\pdfstrcmp{#1}{bbb}=0%
      \href{example.com/bbb}{my bbb link}
   \fi
}
\begin{document}
Here is \myref{aaa}.
\end{document}

But of course once I get a success (#1=aaa, say), I'm still testing the other 149 conditions for no reason. How to code this efficiently?

Answer 1

I would e.g. create command names:

\documentclass{article}
\usepackage{hyperref}
\makeatletter
\@namedef{aaa@link}{\href{example.com/aaa}{my aaa link}}
\@namedef{bbb@link}{\href{example.com/bbb}{my bbb link}}

\newcommand{\myref}[1]{%
 \csname #1@link\endcsname}

\begin{document}
Here is \myref{aaa}.
\end{document}

Answer 2

let biber do the searching for you:

assuming there is a file test.bib with

@online{tex,
  note={my aaa text},
  url={tex.stackexchange.com}
}

@online{google,
  note={my bbb text},
  url={www.google.com}
}

then

\documentclass{article}
\usepackage{biblatex}

\addbibresource{test.bib}

\DeclareFieldFormat{url}{\href{#1}{\printfield{note}}}
\DeclareCiteCommand{\myref}{}{\usebibmacro{url}}{}{}

\usepackage{hyperref}

\begin{document}
Here is \myref{tex}

\myref{google}

\end{document}

Answer 3

You can use xparse:

\pdfcompresslevel=0
\documentclass{article}
\usepackage{xparse}
\usepackage{hyperref}

\ExplSyntaxOn

\NewDocumentCommand{\newref}{mmm}
 {% #1 = key, #2 = URL, #3 = description, #4 = options for \href
  \prop_gput:Nnx \g_tima_sites_prop { #1 @ url } { \tl_to_str:n { #2 } }
  \prop_gput:Nnn \g_tima_sites_prop { #1 @ desc } { #3 }
 }

\NewDocumentCommand{\myref}{m}
 {% #1 = key
  \tima_href:xx
   { \prop_item:Nn \g_tima_sites_prop {#1 @ url } }
   { \prop_item:Nn \g_tima_sites_prop {#1 @ desc } }
 }

\prop_new:N \g_tima_sites_prop
\cs_new_protected:Nn \tima_href:nn { \href{#1}{#2} }
\cs_generate_variant:Nn \tima_href:nn { xx }

\ExplSyntaxOff

\newref{texworks}{http://profs.scienze.univr.it/~gregorio/introtexworks}{\TeX works intro}
\newref{arara}{http://profs.scienze.univr.it/~gregorio/introarara}{Arara intro}
\newref{tex.sx}{https://tex.stackexchange.com}{Nice site}

\begin{document}

\myref{texworks}

\myref{arara}

\myref{tex.sx}

\end{document}