Using extended grapheme clusters as characters means truncation, concatenation, length measurement and transformations like reversal all work in the expected way, even in the presence of combining characters. More standard libraries should consider adopting this model!
The article fails to discuss non-monospaced fonts, which make this problem even more pronounced. For a long time Word would screw up a ligature if it also included a color change. The only hope is length(source_data, rendering_environment) as a function.
I think proportional fonts makes this issue less pronounced because for more people it makes intuitive sense that you can't get string width by just counting characters, and thus they end up using proper measurement functions.
