> a terminal has to represent every non-CJK glyph as a single character cell... Not necessarily. Unicode has a dedicated property called East Asian Width [1] w

> a terminal has to represent every non-CJK glyph as a single character cell... Not necessarily. Unicode has a dedicated property called East Asian Width [1] which effectively affects the terminal rendering, and "Ambiguous" characters like arrows can be configured as full-width (because CJK users expect that). Even when the configuration itself doesn't exist, the font metric may be used to infer the glyph width in this case. [1] https://www.unicode.org/reports/tr11/ https://www.unicode.org/reports/tr11/