https://blogs.embarcadero.com/using-delphis-expressions-engine/
https://github.com/torvalds/linux/blob/master/scripts/kconfig/expr.c
https://beltoforion.de/en/muparser/
C++ Mathematical Expression Library (ExprTk) - By Arash
C library for parsing and evaluating simple expressions.
evaluating expressions
https://stackoverflow.com/questions/1326258/mathematical-expression-parser-in-delphi
https://github.com/Crownie88/Delphi-mathematic-expression-parser/blob/master/MathExpParser.pas