1 Grammar of the schema language {#flatbuffers_grammar} 2 ============================== 3 4 schema = include* 5 ( namespace\_decl | type\_decl | enum\_decl | root\_decl | 6 file_extension_decl | file_identifier_decl | 7 attribute\_decl | rpc\_decl | object )* 8 9 include = `include` string\_constant `;` 10 11 namespace\_decl = `namespace` ident ( `.` ident )* `;` 12 13 attribute\_decl = `attribute` ident | `"`ident`"` `;` 14 15 type\_decl = ( `table` | `struct` ) ident metadata `{` field\_decl+ `}` 16 17 enum\_decl = ( `enum` ident [ `:` type ] | `union` ident ) metadata `{` 18 commasep( enumval\_decl ) `}` 19 20 root\_decl = `root_type` ident `;` 21 22 field\_decl = ident `:` type [ `=` scalar ] metadata `;` 23 24 rpc\_decl = `rpc_service` ident `{` rpc\_method+ `}` 25 26 rpc\_method = ident `(` ident `)` `:` ident metadata `;` 27 28 type = `bool` | `byte` | `ubyte` | `short` | `ushort` | `int` | `uint` | 29 `float` | `long` | `ulong` | `double` | 30 `int8` | `uint8` | `int16` | `uint16` | `int32` | `uint32`| `int64` | `uint64` | 31 `float32` | `float64` | 32 `string` | `[` type `]` | ident 33 34 enumval\_decl = ident [ `=` integer\_constant ] 35 36 metadata = [ `(` commasep( ident [ `:` single\_value ] ) `)` ] 37 38 scalar = integer\_constant | float\_constant 39 40 object = { commasep( ident `:` value ) } 41 42 single\_value = scalar | string\_constant 43 44 value = single\_value | object | `[` commasep( value ) `]` 45 46 commasep(x) = [ x ( `,` x )\* ] 47 48 file_extension_decl = `file_extension` string\_constant `;` 49 50 file_identifier_decl = `file_identifier` string\_constant `;` 51 52 string\_constant = `\".*?\"` 53 54 ident = `[a-zA-Z_][a-zA-Z0-9_]*` 55 56 `[:digit:]` = `[0-9]` 57 58 `[:xdigit:]` = `[0-9a-fA-F]` 59 60 dec\_integer\_constant = `[-+]?[:digit:]+` 61 62 hex\_integer\_constant = `[-+]?0[xX][:xdigit:]+` 63 64 integer\_constant = dec\_integer\_constant | hex\_integer\_constant 65 66 dec\_float\_constant = `[-+]?(([.][:digit:]+)|([:digit:]+[.][:digit:]*)|([:digit:]+))([eE][-+]?[:digit:]+)?` 67 68 hex\_float\_constant = `[-+]?0[xX](([.][:xdigit:]+)|([:xdigit:]+[.][:xdigit:]*)|([:xdigit:]+))([pP][-+]?[:digit:]+)` 69 70 special\_float\_constant = `[-+]?(nan|inf|infinity)` 71 72 float\_constant = decimal\_float\_constant | hexadecimal\_float\_constant | special\_float\_constant 73 74 boolean\_constant = `(true|false)` | (integer\_constant ? `true` : `false`) 75
