Ask HN: Why aren't we using syntax-directed editors

Most editors parse code into an internal syntax tree for highlighting and type-checking and such, but still make us edit the text directly.

This seems ridiculous to me. Syntax and type errors should be impossible to create in the first place. Why aren't we manipulating code directly? Is it hard to learn? Is it hard to use? Has it been tried?

The more I think about it the more odd it seems that we never abstracted beyond raw text.