but I haven’t found anywhere in the RM that defines what specifically tested_simple_expression and choice_simple_expression are vs just a regular simple_expression. The annotated RM wasn’t much more clear on it (unless I just missed something in the text):
If there is an italicized prefix (such as tested_ simple_expression), the prefix is indicating some semantic distinction rather than a syntactic distinction. Syntactically, a prefixed non-terminal is equivalent to the un-prefixed non-terminal (such as “simple_expression”), but semantically there is a difference. In this case, the distinction is given in RM 4.5.2(3.1/5):
You can read about this convention in RM 1.1.4(14), which is the “Method of Description” section of the manual:
If the name of any syntactic category starts with an italicized part, it is equivalent to the category name without the italicized part. The italicized part is intended to convey some semantic information. For example subtype_name and task_name are both equivalent to name alone.
I couldn’t find the terms listed in the index, so I didn’t realize they were more explained in a separate section. So I really do appreciate it! Thank you!