2

I have this code borrowed from a similar stack thread

\newcounter{susis}

\newcommand{\myHyperlink}[2]{%
\refstepcounter{susis}\label{susislink#1}%
\ifcsname r@susistarget#1\endcsname
\hyperlink{#1}{\textcolor{blue}{#2}}%
\else
\hyperlink{#1}{\textcolor{red}{#2}}%
\fi
}

\newcommand{\myHypertarget}[2]{%
\refstepcounter{susis}\label{susistarget#1}%
\ifcsname r@susislink#1\endcsname
\hypertarget{#1}{\textcolor{teal}{#2}}%
\else
\hypertarget{#1}{\fbox{\textcolor{red}{#2}}}%
\fi
}

And it works when I run \myHyperlink{Hello}{Hello}. However, when I try to do \myHyperlink{\lor}{\lor} (logical OR symbol), it says: Missing \endcsname inserted. <to be read again> \lor.

How would I fix this error?

Additional info: I'm trying to target and link math operators. It works with normal hypertarget and hyperlink, but I want to include the additional feature: if the link refers to an undeclared target, it would display in red text instead of blue.

japseow
  • 161
  • 1
    welcome to tex.se! \lor is math expression, so it should be in math environment: $\lor$. if this influence on working of your hyper links, i cant test (you not provide complete small document beginning with \documentclass{...} and ending with \end{document}) – Zarko Feb 04 '18 at 05:39

3 Answers3

1

You need to employ the directive in the form

\myHyperlink{lor}{$\lor$}

Two general recommendations:

  • The first argument should be a simple string -- no macros of any kind

  • If the second argument is a math-mode command, such as \lor, you need to employ math mode to typeset it, i.e., surround \lor with $ symbols.

enter image description here

\documentclass{article}
\usepackage{xcolor,hyperref}
\hypersetup{colorlinks}

\newcounter{susis}
\makeatletter
\newcommand{\myHyperlink}[2]{%
   \refstepcounter{susis}\label{susislink#1}%
   \ifcsname r@susistarget#1\endcsname
      \hyperlink{#1}{\textcolor{blue}{#2}}%
   \else
      \hyperlink{#1}{\textcolor{red}{#2}}%
   \fi
}
\newcommand{\myHypertarget}[2]{%
   \refstepcounter{susis}\label{susistarget#1}%
   \ifcsname r@susislink#1\endcsname
      \hypertarget{#1}{\textcolor{teal}{#2}}%
   \else
      \hypertarget{#1}{\fbox{\textcolor{red}{#2}}}%
   \fi
}
\makeatother

\begin{document}
\myHyperlink{Hello}{Hello} \myHypertarget{Hello}{Hello}

\myHyperlink{lor}{$\lor$} \myHypertarget{lor}{$\lor$}

\myHyperlink{good1}{Good1} \myHypertarget{good2}{Good2}

\myHyperlink{wedge}{$\wedge$} \myHypertarget{dots}{$\dots$}
\end{document}
Mico
  • 506,678
  • 1
    I'm aware that it's discouraged to use macros to for hyperref, but aren't there any workarounds? targeting and linking works perfectly if where weren't any \ifcsnames around.

    Edit: And my notes is full of \land, \lor, \implies, \lnot, etc. and every time I call these things, I want to link them to the original target. It would be very difficult if for each call of \lor, i had to link{lor}{\lor}, instead of simply link{\lor}

     – japseow Feb 04 '18 at 08:33
  • @japseow - Both user-level macros contain the instruction \label{susislink#1}. Some "TeX-special" characters are allowed in the argument of \label -- but not all. In particular, the backslash character isn't allowed. Similarly, the directive \ifcsname r@susistarget#1\endcsname only works if #1 doesn't contain a backslash character. It's for these reasons that one a LaTeX macro that contains a backslash isn't allowed in the first argument of either \myHyperlink} or \myHypertarget}. – Mico Feb 04 '18 at 13:17
1

I would use an approach with an optional argument for the internal name; if it's present, it is used; otherwise, the mandatory argument is used.

However, you need to use $ around \lor, because it's an inherently mathematical command.

The internal name is “stringified” and suitable protection is added around it in the .aux file.

\documentclass{article}
\usepackage[
  paperwidth=5cm,
  paperheight=5cm,
  vmargin=2mm,
  hmargin=0.5cm,
  includehead,includefoot
]{geometry}
\usepackage{xcolor,xparse,hyperref}

\hypersetup{colorlinks}

\newcounter{susis}

\ExplSyntaxOn

\NewDocumentCommand{\myHyperlink}{ O{#2}m }
 {
  \japseow_hyperlink:nn { \tl_to_str:n { #1 } } { #2 }
 }
\NewDocumentCommand{\myHypertarget}{ O{#2}m }
 {
  \japseow_hypertarget:nn { \tl_to_str:n { #1 } } { #2 }
 }

\cs_new_protected:Nn \japseow_hyperlink:nn
 {
  \refstepcounter{susis}\label{susislink\protectlabel{#1}}
  \tl_if_exist:cTF { r@susistarget#1 }
   {
    \hyperlink{#1}{\textcolor{blue}{#2}}
   }
   {
    \hyperlink{#1}{\textcolor{red}{#2}}
   }
 }
\cs_new_protected:Nn \japseow_hypertarget:nn
 {
  \refstepcounter{susis}\label{susistarget\protectlabel{#1}}
  \tl_if_exist:cTF { r@susislink#1 }
   {
    \hypertarget{#1}{\textcolor{teal}{#2}}
   }
   {
    \hypertarget{#1}{\fbox{\textcolor{red}{#2}}}
   }
}
\NewDocumentCommand\protectlabel{m}
 {
  \tl_to_str:n { #1 }
 }
\ExplSyntaxOff

\begin{document}

\myHyperlink{Hello}\clearpage

\myHypertarget{Hello}\clearpage

\myHyperlink{$\lor$}\clearpage

\myHypertarget{$\lor$}\clearpage

\myHyperlink[weird]{This is too weird for using as a link}\clearpage

\myHypertarget[weird]{Good2}\clearpage

\myHypertarget[ops]{Whatever}

\end{document}

enter image description here

egreg
  • 1,121,712
  • Wow it works! But, I'm having a problem in my \begin{tcolorbox} \begin{align} ... \end{align} \end{tcolorbox}. I'm getting: Multiple \label's: label 'susistarget\protectlabel {unusedlabed}' will be lost. whenever I try to use the myHypertarget within the tcolorbox and align – japseow Feb 04 '18 at 13:30
  • It seems to happen when I have a hypertarget and hyperlink at the same line (even if the link doesn't refer to the target) – japseow Feb 04 '18 at 13:37
  • @japseow With align it's a very different thing, I'm afraid. – egreg Feb 04 '18 at 13:43
  • I'm not very well-versed in LaTex, but will this solution work?

    I create a dynamic array/arraylist of strings. Whenever I create a new hypertarget, I add the "string-ified" input into the arraylist.

    Then when I call a new hyperlink, it checks if the stringified input is contained in the arraylist. If not, color it red instead of blue.

    Though, I don't even have a clue on how to implement it.

     – japseow Feb 04 '18 at 15:12
0

The desired functionality can be accomplished by combining these answers:

https://tex.stackexchange.com/a/168835/143704

https://tex.stackexchange.com/a/30484/143704

japseow
  • 161