From: A systematic process for obtaining the behavior of context-sensitive systems
Expression | Meaning | Example |
---|---|---|
blank space | Sequence | (t1 t2), first t1 and then t2 |
| | Alternative | (t1 |t2), t1 xor t2 |
? | Optional | (t1 t2? t3), first t1 and then t3, or first t1 followed by t2 and t3 |
* | Zero or more times | (t1 t2* t3), first t1, then t2 zero or more times, then t3 |
+ | One or more times | (t1 t2+), first t1, then t2 one or more times |
- | Parallelism | t1-t2, t1 is executed at the same time as t2. |