This is a very selective description of changes. The git commit log is the complete source for all changes.
Made a few small additions to these files:
p4-16-allowed-constructs.dotp4-16-allowed-constructs.txt
Added 'if' explicitly as something not allowed inside a parser state to the figure. The text version has had that for a while now, but it seemed prudent to add it to the figure version, since 'if' statements are commonly desired statements when writing programs, and I went to the trouble to investigate where the language spec allows and does not allow 'if' statements.
Added 'if' as something explicitly allowed inside a function definition.
Added note on 'if' inside of action declaration that the language spec explicitly allows implementations not to support 'if' inside of actions.
Added edge from 'switch' statement to the box representing allowed statements inside of blocks.