How to define acronyms in ConTeXt?

Question

The acronym packages allows one to easily create and display acronyms, with a simple syntax, like \ac{usb}. The first time this is called, is will say “Universal Serial Bus (USB)”, but after that, just “USB”. I found nothing about this in the documentation, but this article on PDF-strings seems to offer similar functionality, but the example seems incomplete. How can I define and display acronyms in ConTeXt?

Answer 1

The context version of this functionality is called 'synonyms', types of which are defined using \definesynonyms. The wiki page for definesynonyms contains some examples, but in short:

\definesynonyms[acronym][acronyms][\infull]

\acronym[VVV]{vvv}{Bureau of Tourist Information}
\starttext
The Dutch \VVV\ (\infull{VVV}) can provide you with the tourist information on Hasselt.
\stoptext

There now also a \setupsynonyms[acronyms] and \placelistofacronyms. That are used to produce a list of (used or all) acronyms.

As far as I know, ConTeXt does not have a built-in feature for 'first use'.

Answer 2

The theory behind this is easy, if you don't need to index the acronyms.

\def\newacronym#1#2#3{% #1 = key, #2 = abbreviated form, #3 = expanded form
  \expandafter\def\csname ac@#1\endcsname{%
    #3~(#2)%
    \expandafter\gdef\csname ac@#1\endcsname{#2}%
   }%
}
\def\ac#1{\csname ac@#1\endcsname}

\newacronym{usb}{USB}{Universal Serial Bus}
\newacronym{ml}{ML}{Murphy's Law}

Here's \ac{usb} and \ac{ml}; let's see that \ac{usb} works 
not according to \ac{ml}.

\bye