Feature request: make using variables easier

[yann-soubeyrand]

Hello,

I find that using strings to reference elements prevents us from taking advantage of the features offered by our IDEs (like static analysis, re-factoring, etc.). However, defining variables brings a lot of scopes challenges.

The following does not work:

var _ = Design(func() {
	SoftwareSystem("mysystem1", func() {
		container1 := Container("mycontainer1", func() {
		})
	})

	SoftwareSystem("mysystem2", func() {
		Container("mycontainer2", func() {
			Uses(container1, "Uses")
		})
	})
})

We have to pre-declare variables like the following:

var _ = Design(func() {
	var container1 *expr.Container
	
	SoftwareSystem("mysystem1", func() {
		container1 = Container("mycontainer1", func() {
		})
	})

	SoftwareSystem("mysystem2", func() {
		Container("mycontainer2", func() {
			Uses(container1, "Uses")
		})
	})
})

I would like to be able to write something like the following instead:

var _ = Design(func() {
	system1 := SoftwareSystem("mysystem1", func() {
	})

	container1 := system1.AddContainer(Container("mycontainer1", func() {
	}))

	SoftwareSystem("mysystem2", func() {
		Container("mycontainer2", func() {
			Uses(container1, "Uses")
		})
	})
})

[raphael]

That makes sense. As you know the DSL is currently purely descriptive, that is all DSL functions are global functions, there is no method. The idea is to keep it simple and easy to use even for people that might not be software engineers.

That being said adding more flexibility like suggested above does have the potential to really increase the expressiveness of the DSL. We would have to be very judicious and careful about the newly introduced DSL to make sure the trade-off is worth it.

TL;DR I would love to see a more flushed out proposal!