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74 lines
2.5 KiB
Markdown
74 lines
2.5 KiB
Markdown
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# Python for RiveScript Go
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It'd be nice if rivescript-go were able to parse and run Python object macros for RiveScript bots, by using the [Python C API](https://docs.python.org/3/c-api/index.html).
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There are two projects I found so far: [sbinet/go-python](https://github.com/sbinet/go-python) and [qur/gopy](https://github.com/qur/gopy). They both only support Python 2 so far, but that will work for now.
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I did some experimenting and came up with the following Go code that demonstrates the key pieces of functionality needed: dynamically parse a Python function, call the function giving it an array of string arguments, and retrieve the result of the function as a Go string.
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```go
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package main
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import (
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"fmt"
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"github.com/sbinet/go-python"
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)
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func init() {
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err := python.Initialize()
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if err != nil {
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panic(err.Error())
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}
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}
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func main() {
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// The source code of the python function we wanna be able to call.
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pycode := `
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def test(rs, args):
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print "Test works"
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return "Forwards: {}\nBackwards: {}".format(
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" ".join(args),
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" ".join(args[::-1]),
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)
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`
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// The []string to use as the 'args' param to `def test()`
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args := StringList_ToPython("Hello", "world")
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defer args.DecRef() // Always do this so Python can count references well.
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// To load the function you can simply eval the code in the global scope:
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python.PyRun_SimpleString(pycode)
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// Get the main module's dictionary so we can get a reference to our
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// function back out of it.
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main_module := python.PyImport_AddModule("__main__")
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main_dict := python.PyModule_GetDict(main_module)
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test_function := python.PyDict_GetItemString(main_dict, "test")
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// The tuple of (rs, args) arguments to pass to the function.
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// This tuple is the *args in Python lingo.
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test_args := python.PyTuple_New(2)
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python.PyTuple_SetItem(test_args, 0, python.Py_None)
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python.PyTuple_SetItem(test_args, 1, StringList_ToPython("Hello", "world"))
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// Call the actual Python function now. Functions return a *PyObject, and
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// we can cast it back to a string.
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returned := test_function.CallObject(test_args)
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result := python.PyString_AsString(returned)
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// Print the result of the function.
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fmt.Println("Result:", result)
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}
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// StringList_ToPython is a helper function that simply converts a Go []string
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// into a Python List of the same length with the same contents.
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func StringList_ToPython(items... string) *python.PyObject {
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list := python.PyList_New(len(items))
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for i, item := range items {
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python.PyList_SetItem(list, i, python.PyString_FromString(item))
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}
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return list
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}
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```
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