The "Grammar and Parser" of the "Custom Language Support Tutorial" says "Note that the
SimpleTypes class in the
elementTypeHolderClass attribute above specifies the name of a class that gets generated from the grammar; it doesn't exist at this point".
But the "Lexer and Parser Definition" starts using SimpleTypes class after generating a Lexer class by Simple.flex file with JFlex Generator. And does't describe how to write the
SimpleTypes class before or after.
How do I write a org.intellij.sdk.language.psi.SimpleTypes?