Lookup table in Latex

Question

I have a bunch of automatically generated LaTeX code with hypertargets of the form "functionname_2093840289fad1337", i.e the name of a function with a hash appended. I would like to refer to those functions from the rest of the document by only referring to the function name which I know is unique. I would like a lookup function something like this:

\hyperdyperlink{functionname}

that emits

\hyperlink{functionname_2093840289fad1337}{functionname}

Note that I can't calculate the hash but I'm prepared to write a table that maps each functionname to functionname+hash. What's the best way to write this kind of function?

Slack

Answer 1

Does this work?

\makeatletter
\newcommand\hashlink[2]{%
    \@namedef{hashlink-#1}{#2}%
}
\newcommand\hyperdyperlink[1]{%
    \hyperlink
    {#1_\@nameuse{hashlink-#1}}
    {#1}%
}
\hashlink{functionname}{2093840289fad1337}
\hyperdyperlink{functionname}
\makeatother

(Untested.)

---

Later: To branch the code depending if you've defined the link target, you can write something like

\newcommand\hyperdyperlink[1]{%
    \@ifundefined{hashlink-#1}{%
    [whatever else you want to do]
    }{%
    \hyperlink{#1_\@nameuse{hashlink-#1}}{#1}%
    }%
}

(Update: oops; that was pretty broken as first posted, sorry. Now fixed, I hope.)

Grunberg

Only problem I've found is that I get a really hairy error if I haven't defined the link target yet. Is it possible to see if a name exist and do something different (like linking to {} or similar?) – Slack

Answer 2

Since the function names are unique, could you not define the hyperlink targets without the hash appended?

Alternatively, you could create a new LaTeX macro for each function. The code that generates the LaTeX code could do this by outputting code like this:

\newcommand{\linkFoo}{\hyperlink{foo_2093840289fad1337}{foo}}
\newcommand{\linkBar}{\hyperlink{bar_4323812312asf1342}{bar}}

Then use \linkFoo and friends in your hand-written part.

You could also implement a proper lookup table with TeX macros if you really wanted -- see this thread for an example -- but this solution is quite easy and simpler to understand (IMHO).

Gaekwar

Thanks for the comment. The hashes represents the parameter lists and return types but we work with C symbols only which doesn't support overloading of function names. – Slack

@Will: ah, I guess you mean to point out that \ifcase is only for integer cases... that makes sense now that I think of it with the \today macro :-) – Gaekwar

I've removed the \ifcase example since it didn't make much sense. – Gaekwar

You also wouldn't have wanted to count from zero all the way up to 2093840289fad1337 number of \or's :) – Grunberg