====== ALIASFN ======

//Since version 2.2//

Syntax:

  aliasfn <const int address>, "<function name>"
  
The ''ALIASFN'' directive registers a new function alias in order to make it possible to call a user function without the ''USR'' keyword. This directive is mainly used in extensions.

The function name must be a valid identifier - i. e. it starts with an alpha char or underscore and contains alphanumeric chars and underscores only. It may be appended with a sigil - any of these characters: ''!#%$'' indicating that the function alias refers to a function that returns a specific type. The default is ''#'' (integer).

The same alias for different types is allowed and encouraged, for example you can define the aliases ''myFunc!'' and ''myFunc#'' that point to different addresses.

Example:

  aliasfn $c000, "myfunc"
  
  rem -- Assuming that a machine code function resides at address $C000,
  rem -- the following two function calls are identical:
  
  x = usr($c000, arg1, arg2)
  y = myfunc(arg1, arg2)