75 lines
2.2 KiB
Markdown
75 lines
2.2 KiB
Markdown
Grammar of the schema language {#flatbuffers_grammar}
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==============================
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schema = include*
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( namespace\_decl | type\_decl | enum\_decl | root\_decl |
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file_extension_decl | file_identifier_decl |
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attribute\_decl | rpc\_decl | object )*
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include = `include` string\_constant `;`
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namespace\_decl = `namespace` ident ( `.` ident )* `;`
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attribute\_decl = `attribute` ident | `"` ident `"` `;`
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type\_decl = ( `table` | `struct` ) ident metadata `{` field\_decl+ `}`
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enum\_decl = ( `enum` ident `:` type | `union` ident ) metadata `{`
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commasep( enumval\_decl ) `}`
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root\_decl = `root_type` ident `;`
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field\_decl = ident `:` type [ `=` scalar ] metadata `;`
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rpc\_decl = `rpc_service` ident `{` rpc\_method+ `}`
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rpc\_method = ident `(` ident `)` `:` ident metadata `;`
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type = `bool` | `byte` | `ubyte` | `short` | `ushort` | `int` | `uint` |
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`float` | `long` | `ulong` | `double` |
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`int8` | `uint8` | `int16` | `uint16` | `int32` | `uint32`| `int64` | `uint64` |
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`float32` | `float64` |
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`string` | `[` type `]` | ident
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enumval\_decl = ident [ `=` integer\_constant ] metadata
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metadata = [ `(` commasep( ident [ `:` single\_value ] ) `)` ]
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scalar = boolean\_constant | integer\_constant | float\_constant
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object = `{` commasep( ident `:` value ) `}`
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single\_value = scalar | string\_constant
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value = single\_value | object | `[` commasep( value ) `]`
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commasep(x) = [ x ( `,` x )\* ]
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file_extension_decl = `file_extension` string\_constant `;`
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file_identifier_decl = `file_identifier` string\_constant `;`
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string\_constant = `\".*?\"`
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ident = `[a-zA-Z_][a-zA-Z0-9_]*`
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`[:digit:]` = `[0-9]`
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`[:xdigit:]` = `[0-9a-fA-F]`
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dec\_integer\_constant = `[-+]?[:digit:]+`
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hex\_integer\_constant = `[-+]?0[xX][:xdigit:]+`
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integer\_constant = dec\_integer\_constant | hex\_integer\_constant
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dec\_float\_constant = `[-+]?(([.][:digit:]+)|([:digit:]+[.][:digit:]*)|([:digit:]+))([eE][-+]?[:digit:]+)?`
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hex\_float\_constant = `[-+]?0[xX](([.][:xdigit:]+)|([:xdigit:]+[.][:xdigit:]*)|([:xdigit:]+))([pP][-+]?[:digit:]+)`
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special\_float\_constant = `[-+]?(nan|inf|infinity)`
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float\_constant = dec\_float\_constant | hex\_float\_constant | special\_float\_constant
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boolean\_constant = `true` | `false`
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