Interestingly, nobody mentioned Mathematica's (Wolfram langauge) approach of getting Unicode characters into code. "High level" mathematical symbols can be used

Interestingly, nobody mentioned Mathematica's (Wolfram langauge) approach of getting Unicode characters into code. "High level" mathematical symbols can be used in Wolfram language all over the place, for instance the arrow → indicating a Rule (http://reference.wolfram.com/language/ref/character/Rule.html http://reference.wolfram.com/language/ref/character/Rule.htm...) or ∞ indicating Infinity (http://reference.wolfram.com/language/ref/Infinity.html http://reference.wolfram.com/language/ref/Infinity.html). As Mathematica inherits the homoiconicity from LISP, ie. the paradigm "code is data", it abstracts the code representation (called "Forms", http://reference.wolfram.com/language/tutorial/FormsOfInputAndOutput.html http://reference.wolfram.com/language/tutorial/FormsOfInputA...). Every shortened code full of greek symbols can be written in a completely similar form in ASCII. Thus it is solely to the Mathematica notebook (a Qt-based GUI) to render the Unicode. The GUI also allows to quickly enter any named symbols with an approach like typing "[ESC] alpha [ESC]" and an α appears (cf. http://reference.wolfram.com/language/tutorial/SpecialCharacters-MathematicalAndOtherNotation.html http://reference.wolfram.com/language/tutorial/SpecialCharac...). I think this is the right approach: Let the beautification to be done by the code viewers. The approach to enter named symbols probably stems from (La)TeX where one writes "$\alpha$" to get α and is typical to Computer Algebra Systems. For instance, SageMath as well as SymPy allow to define something like a=var("alpha") and render it like α.