Mathematica is the earliest thing I am aware of with this feature where it was Alt+. to expand selection in their notebook interface starting in the early 90s. But the thing I miss most that I still can't shake the muscle memory of after almost a decade of not using much Mathematica, is that single/double/triple/n-click scaled this way as well. So double-click selected a whole word (as in all editors), triple-click selected all the comma-separated multiple args of a function, 4-click for f(a,r,g,s), and so on.