This is the complete grammar for Tosh in BNF syntax. It shows you the actual rules which the parser uses.
It's mostly useful for testing and debugging Tosh itself, although it can be useful if you want to get a precise idea of how Tosh's syntax works. You're probably better off reading the guide, honestly.
The rules for the core grammar were defined by hand. The rest of the blocks are generated from the actual Scratch 2.0 definitions using code.