1Use in Lobster {#flatbuffers_guide_use_lobster}
2==============
3
4## Before you get started
5
6Before diving into the FlatBuffers usage in Lobster, it should be noted that the
7[Tutorial](@ref flatbuffers_guide_tutorial) page has a complete guide to general
8FlatBuffers usage in all of the supported languages (including Lobster). This
9page is designed to cover the nuances of FlatBuffers usage, specific to
10Lobster.
11
12You should also have read the [Building](@ref flatbuffers_guide_building)
13documentation 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 Lobster library code location
18
19The code for the FlatBuffers Lobster library can be found at
20`flatbuffers/lobster`. You can browse the library code on the
21[FlatBuffers GitHub page](https://github.com/google/flatbuffers/tree/master/
22lobster).
23
24## Testing the FlatBuffers Lobster library
25
26The code to test the Lobster library can be found at `flatbuffers/tests`.
27The test code itself is located in [lobstertest.lobster](https://github.com/google/
28flatbuffers/blob/master/tests/lobstertest.lobster).
29
30To run the tests, run `lobster lobstertest.lobster`. To obtain Lobster itself,
31go to the [Lobster homepage](http://strlen.com/lobster) or
32[github](https://github.com/aardappel/lobster) to learn how to build it for your
33platform.
34
35## Using the FlatBuffers Lobster library
36
37*Note: See [Tutorial](@ref flatbuffers_guide_tutorial) for a more in-depth
38example of how to use FlatBuffers in Lobster.*
39
40There is support for both reading and writing FlatBuffers in Lobster.
41
42To use FlatBuffers in your own code, first generate Lobster classes from your
43schema with the `--lobster` option to `flatc`. Then you can include both
44FlatBuffers and the generated code to read or write a FlatBuffer.
45
46For example, here is how you would read a FlatBuffer binary file in Lobster:
47First, import the library and the generated code. Then read a FlatBuffer binary
48file into a string, which you pass to the `GetRootAsMonster` function:
49
50~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~{.lobster}
51 include "monster_generated.lobster"
52
53 let fb = read_file("monsterdata_test.mon")
54 assert fb
55 let monster = MyGame_Example_GetRootAsMonster(fb)
56~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
57
58Now you can access values like this:
59
60~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~{.lobster}
61 let hp = monster.hp
62 let pos = monster.pos
63~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
64
65As you can see, even though `hp` and `pos` are functions that access FlatBuffer
66data in-place in the string buffer, they appear as field accesses.
67
68## Speed
69
70Using FlatBuffers in Lobster should be relatively fast, as the implementation
71makes use of native support for writing binary values, and access of vtables.
72Both generated code and the runtime library are therefore small and fast.
73
74Actual speed will depend on whether you use Lobster as bytecode VM or compiled to
75C++.
76
77## Text Parsing
78
79Lobster has full support for parsing JSON into FlatBuffers, or generating
80JSON from FlatBuffers. See `samples/sample_test.lobster` for an example.
81
82This uses the C++ parser and generator underneath, so should be both fast and
83conformant.
84
85<br>
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