doc/manual/dollar-ref.tex

   1 \section[Dollar extension]{{\tt dollar}: generic syntax for macros}
   2 When you write a short-lived macro which takes reasonably short arguments, you
   3 generally don't want to write a supporting syntax for it. The dollar library
   4 allows you to call it in a generic way: if you store your macro in the table
   5 {\tt mlp.macros}, say as function {\tt mlp.macros.foobar}, then you can call it
   6 in your code as {\tt\$foobar(arg1, arg2...)}: it will receive as parameters the
   7 ASTs of the pseudo-call's arguments.
   8
   9 \paragraph{Example}~
  10 \begin{verbatim}
  11 -{ block:
  12    require 'dollar'
  13    function doller.LOG(id)
  14       match id with `Id{ id_name } ->
  15          return +{ printf("%s = %s", id_name,
  16                           table.tostring(-{id})) }
  17       end
  18    end }
  19
  20 local x = { 1, 2, 3 }
  21 $LOG(x) -- prints "x = { 1, 2, 3 }" when executed
  22 \end{verbatim}