py/README

py/README.md

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+Linking Python to Go
+=====
+
+TODO
+
+## Demo
+
+The `_demo` directory contains our demos (it start with `_` to prevent the `go` command from compiling it):
+
+* [hellopy](_demo/hellopy/hello.go): link Python to Go and say `Hello world`
+* [clpy](_demo/clpy/cleval.go): compile Python code and eval.
+* [callpy](_demo/callpy/call.go): call Python standard library function `math.sqrt`.
+
+### How to run demos
+
+To run the demos in directory `_demo`, you need to set the `LLGO_LIB_PYTHON` environment variable first. Assuming you use Python 3.12, and the `libpython3.12.so` (or `libpython3.12.dylib` or `python3.12.lib`) file is in the /foo/bar directory, then you need to set `LLGO_LIB_PYTHON` to:
+
+```sh
+export LLGO_LIB_PYTHON=/foo/bar/python3.12
+```
+
+For example, `/opt/homebrew/Frameworks/Python.framework/Versions/3.12/libpython3.12.dylib` is a typical python lib location under macOS. So we should set it like this:
+
+```sh
+export LLGO_LIB_PYTHON=/opt/homebrew/Frameworks/Python.framework/Versions/3.12/python3.12
+```
+
+Then you can run the demos in directory `_demo`:
+
+```sh
+cd <demo-directory>  # eg. cd _demo/hellopy
+llgo run .
+```

py/_demo/callpy/call.go

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+package main
+
+import (
+	"github.com/goplus/llgo/c"
+	"github.com/goplus/llgo/py"
+)
+
+func main() {
+	py.Initialize()
+	py.SetProgramName(*c.Argv)
+	math := py.ImportModule(c.Str("math"))
+	sqrt := math.GetAttrString(c.Str("sqrt"))
+	sqrt2 := sqrt.CallOneArg(py.Float(2)).FloatAsDouble()
+	c.Printf(c.Str("sqrt(2) = %f\n"), sqrt2)
+	py.Finalize()
+}

py/_demo/clpy/cleval.go

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+package main
+
+import (
+	"github.com/goplus/llgo/c"
+	"github.com/goplus/llgo/py"
+)
+
+func main() {
+	py.Initialize()
+	py.SetProgramName(*c.Argv)
+	code := py.CompileString(c.Str(`print('Hello, World!')`), c.Str(`hello.py`), py.EvalInput)
+	if code != nil {
+		mod := py.ImportModule(c.Str("__main__"))
+		gbl := mod.GetDict()
+
+		result := py.EvalCode(code, gbl, nil)
+
+		result.DecRef()
+		mod.DecRef()
+		code.DecRef()
+	}
+	py.Finalize()
+}

py/_demo/hellopy/hello.go

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+package main
+
+import (
+	"github.com/goplus/llgo/c"
+	"github.com/goplus/llgo/py"
+)
+
+func main() {
+	py.Initialize()
+	py.SetProgramName(*c.Argv)
+	py.RunSimpleString(c.Str(`print('Hello, World!')`))
+	py.Finalize()
+}