The main class of the program.
Sys is a singleton class, its only instance is accessible from everywhere with
Because of this, methods that should be accessible from everywhere, like
are defined in
Moreover, unless there is an ambiguity with
self, the receiver of a call to these methods is implicitly
Basically it means that the two following instructions are equivalent.
print "Hello World" sys.print "Hello World"
Methods Implicitly Defined in Sys
Sys is the class where are defined top-level methods,
i.e. those defined outside of any class like in a procedural language.
Basically it means that
redef class Sys fun foo do print "hello" end
is equivalent with
fun foo print "hello"
As a corollary, in a top-level method,
self (the current receiver) is always