Where to use which grammar rules
The following graphic depicts which grammar rules are to be used for which part of a graphical protocol definition in Pda:

| No. | Non-terminal symbol | Description |
|---|---|---|
| 1 | ProtDecl | Protocol declarations |
| 2 | AgentNameIdentifier | Agent declarations |
| 3 | Terms | Input/output terms of agents (optional) |
| 4 | AgentAction | Local agent actions (might be empty) |
| 5 | SendReceive | Send/Receive action specs (might be empty) |