move python demos to _pydemo

README.md

@@ -37,6 +37,11 @@ go install -v ./...
 TODO
 
 
+## Python support
+
+TODO
+
+
 ## Demo
 
 The `_demo` directory contains our demos (it start with `_` to prevent the `go` command from compiling it):
@@ -46,13 +51,37 @@ The `_demo` directory contains our demos (it start with `_` to prevent the `go`
 * [qsort](_demo/qsort/qsort.go): call C function with a callback (eg. qsort)
 * [genints](_demo/genints/genints.go): various forms of closure usage (including C function, recv.method and anonymous function)
 * [llama2-c](_demo/llama2-c): inference Llama 2 (It's the first llgo AI example)
+
+And the `_pydemo` directory contains python related demos:
+
 * [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`:
+
 ```sh
 cd <demo-directory>  # eg. cd _demo/genints
 llgo run .
 ```
+
+To run the demos in directory `_pydemo`, 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 `_pydemo`:
+
+```sh
+cd <demo-directory>  # eg. cd _pydemo/hellopy
+llgo run .
+```

py/python.go

@@ -23,7 +23,7 @@ import (
 )
 
 const (
-	LLGoPackage = "link: $LLGO_PYTHON_ROOT/python3.12"
+	LLGoPackage = "link: $LLGO_LIB_PYTHON"
 )
 
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