module join;

context Collection(OclAny) def : join(f : Lambda(OclAny, OclAny) : OclAny) : OclAny =
	self->iterate(e; acc : OclAny = OclUndefined |
		if acc.oclIsUndefined() then
			e
		else 
			f(acc, e)
		endif
	);

context Env static def : main() : Set(String) =
	env.modules.getKeys()->join(x, y | x + ', ' + y).debug('module names');