+Parameters >> +Lambdacall(Lambda,A1,...), 
but arguments are reordered according to the list Parameters:
- The first 
length(Parameters)arguments from A1, ... are unified with (a copy of) Parameters, which may share them with variables in Lambda. - Possible excess arguments are passed by position.
 
| Parameters | is either a plain list of 
parameters or a term
{Free}/List. Free represents variables that are 
shared between the context and the Lambda term. This is 
needed for compiling Lambda expressions.  |