1 Use in Lua {#flatbuffers_guide_use_lua} 2 ============= 3 4 ## Before you get started 5 6 Before diving into the FlatBuffers usage in Lua, it should be noted that the 7 [Tutorial](@ref flatbuffers_guide_tutorial) page has a complete guide to general 8 FlatBuffers usage in all of the supported languages (including Lua). This 9 page is designed to cover the nuances of FlatBuffers usage, specific to 10 Lua. 11 12 You should also have read the [Building](@ref flatbuffers_guide_building) 13 documentation to build `flatc` and should be familiar with 14 [Using the schema compiler](@ref flatbuffers_guide_using_schema_compiler) and 15 [Writing a schema](@ref flatbuffers_guide_writing_schema). 16 17 ## FlatBuffers Lua library code location 18 19 The code for the FlatBuffers Lua library can be found at 20 `flatbuffers/lua`. You can browse the library code on the 21 [FlatBuffers GitHub page](https://github.com/google/flatbuffers/tree/master/lua). 22 23 ## Testing the FlatBuffers Lua library 24 25 The code to test the Lua library can be found at `flatbuffers/tests`. 26 The test code itself is located in [luatest.lua](https://github.com/google/ 27 flatbuffers/blob/master/tests/luatest.lua). 28 29 To run the tests, use the [LuaTest.sh](https://github.com/google/flatbuffers/ 30 blob/master/tests/LuaTest.sh) shell script. 31 32 *Note: This script requires [Lua 5.3](https://www.lua.org/) to be 33 installed.* 34 35 ## Using the FlatBuffers Lua library 36 37 *Note: See [Tutorial](@ref flatbuffers_guide_tutorial) for a more in-depth 38 example of how to use FlatBuffers in Lua.* 39 40 There is support for both reading and writing FlatBuffers in Lua. 41 42 To use FlatBuffers in your own code, first generate Lua classes from your 43 schema with the `--lua` option to `flatc`. Then you can include both 44 FlatBuffers and the generated code to read or write a FlatBuffer. 45 46 For example, here is how you would read a FlatBuffer binary file in Lua: 47 First, require the module and the generated code. Then read a FlatBuffer binary 48 file into a `string`, which you pass to the `GetRootAsMonster` function: 49 50 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~{.lua} 51 -- require the library 52 local flatbuffers = require("flatbuffers") 53 54 -- require the generated code 55 local monster = require("MyGame.Sample.Monster") 56 57 -- read the flatbuffer from a file into a string 58 local f = io.open('monster.dat', 'rb') 59 local buf = f:read('*a') 60 f:close() 61 62 -- parse the flatbuffer to get an instance to the root monster 63 local monster1 = monster.GetRootAsMonster(buf, 0) 64 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 65 66 Now you can access values like this: 67 68 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~{.lua} 69 -- use the : notation to access member data 70 local hp = monster1:Hp() 71 local pos = monster1:Pos() 72 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 73 74 75 ## Text Parsing 76 77 There currently is no support for parsing text (Schema's and JSON) directly 78 from Lua, though you could use the C++ parser through SWIG or ctypes. Please 79 see the C++ documentation for more on text parsing. 80 81 <br> 82
