In C++ you can make a macro function that takes any number of arguments but does nothing. I end up using that to label a scope because that scope block will then collapse in the IDE. I usually declare any variables that are going to be 'output' by that scope block just above it.
This creates the ability to break down isolated parts of a long function that don't need to be repeated. Variables being used also don't need to be declared as function inputs which also simplifies things significantly compared to a function.
This doesn't address making the compiler enforce much, though it does show that anything declared in the scope doesn't pollute the large function it is in.
I wish more IDEs had the ability to chunk code like this on-the-fly. I think it's technically possible, and maybe even possible to insert artificial blocks automatically, showing you how your code layout chunks automatically... Hmm.
You know, once I'm less busy I might try implementing something like this.
auto result_value = [var1, var2, &var3]() {
var3 = var1 + var2
return var1 * var2
}()
return result_value * 5
E.g. something like:
You could also define which variables defined in the block get elevated, like return values: This is also a more tailored solution to the problem than a function, it allows finer-grained control over scope restriction.It's frustrating that most existing languages don't have this kind of feature. Regular scope blocks suck because they don't allow you to define the specific ways in which they are permeable, so they only restrict scope in one direction (things inside the scope block are restricted) - but the outer scope is what you really want to restrict.
You could also introduce this functionality to IDEs, without modifying existing languages. Highlight a few lines, and it could show you a pop-up explaining which variables that section reads, mutates and defines. I think that would make reading long pieces of code significantly easier.