Module macro.lambda
Short anonymous functions (lambdas).
This syntax is suited to any naive token-processor because the payload is always inside parens. It is an example of a macro associated with a 'operator' character.
Syntax is \<args>(<expr>)
\x(x+10) is short for
function(x) return x+10 end. There may be a number of formal argumets,
e.g. \x,y(x+y) or there may be none, e.g. \(somefun()). Such functions
may return multiple values, e.g \x(x+1,x-1).