Ask HN: International Keyboard Layouts and Programming Syntax

I have been reading some older threads on HN and in other places and came across several comments and discussions about how punctuation characters in programming language syntax is or can be cumbersome for users of non-English keyboard layouts. The character that prompted this to stick in my mind was the ‘\’ and it’s non-ease of use for both Germanic and Japanese layouts. Other than sticking with letter based syntax, is there any consensus on what is the common denominator set of characters usable without complex multiple key modifiers in a global context?