Emojis also severely lack semantics. They are specified in terms of what they should visually depict, not what they are supposed to mean.

Usage rather than specifications determine semantics and due to the points in my previous post those often disagree for Unicode emojis.

I'm glad you recognise the value of usage when it comes to emoticons vs. emoji...

emoji lack clear semantics too, consider the eggplant.

I think there's a difference. The code point will always mean "eggplant", it just happens that the concept can be interpreted in different ways according to context—just like the word itself. But ":-)" can only ever mean "colon minus rparens" before further interpretation.

What’s it called is syntax, what it’s means is always context dependent. That’s why we invented formal notation, so that we can have context free interpretation (it’s bundled with its semantic so you don’t need to apply some context to it)

Actually, according to Unicode, "-" doesn't mean minus - U+002D is hyphen-minus.

And as for the eggplant, your semantics-as-specified are useless when 99.9% of the usage has a different intended meaning due to the inherent lack of expressiveness in a corporate-approved emoji language.