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62 lines
2.1 KiB
Plaintext
62 lines
2.1 KiB
Plaintext
{0 Example backend plugins }
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This directory contains backend plugins that demonstrate how those can be
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written and used with Catala. They probably don't provide much value otherwise.
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Use [make plugins] from the root of the source tree to build them.
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A plugin is created by writing an OCaml module that calls
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[Driver.Plugin.register_lcalc] or [Driver.Plugin.register_scalc] and that links
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against [catala.driver]. Here is an example dune stanza to compile it:
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{v
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(executable
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(name my-plugin)
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(modes plugin)
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(modules my_plugin_main_module)
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(libraries catala.driver))
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v}
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See the following module for the registration interface:
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{!modules: Driver.Plugin}
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{1 Using plugins}
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Plugins are dynamically loaded. The Catala compiler will be looking for them at
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startup within [<prefix>/lib/catala/plugins] (assuming that the compiler is
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installed into [<prefix>/bin]), or any other directory specified through the
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`--plugin-dir` command-line flag or by setting the [CATALA_PLUGINS] environment
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variable.
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The plugin of your choice can then be called just like the built-in backends, using:
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{v
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$ catala MyPlugin <file> [options]
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v}
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{1 Examples}
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{2 python example}
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This trivial example registers a plugin that uses the [scalc] format as input.
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It simply calls the code of the built-in Python backend, and should be no
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different to using the normal Catala Python output mode.
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{2 [js_of_ocaml] wrapper generator example}
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This plugin generates a [js_of_ocaml] wrapper from the [lcalc] representation
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of a Catala program.
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It start by generating the OCaml module before generating the [_api_web.ml]
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one, which contains all the class types and conversion functions between the
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OCaml types and their corresponding JS objects. At the end the module exposes
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all methods in a JS lib [<module_name>Lib].
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See the `law_source/` directory in the
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{{:https://catalalang.github.io/catala/french_law_ocaml.tar.gz}
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OCaml french law bundle} for examples of generated code.
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{2 JSON schema generator example}
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This plugin generates a {{:https://json-schema.org} JSON schema} corresponding
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to a scope of a Catala program.
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