Calling Python function from Go and getting the function return value

Question

I am writing a Go program. From this Go program, I would like to call a Python function defined in another file and receive the function\'s return value so I can use it in

Answer 1

I managed to have some working code for this by simply removing the quote around the command itself:

package main

import "fmt"
import "os/exec"

func main() {
    cmd := exec.Command("python",  "-c", "import pythonfile; print pythonfile.cat_strings('foo', 'bar')")
    fmt.Println(cmd.Args)
    out, err := cmd.CombinedOutput()
    if err != nil { fmt.Println(err); }
    fmt.Println(string(out))
}

And sure enough, in the source, you have this function (for Windows, at least, I don't know if that works for other OSes):

// EscapeArg rewrites command line argument s as prescribed
// in http://msdn.microsoft.com/en-us/library/ms880421.
// This function returns "" (2 double quotes) if s is empty.
// Alternatively, these transformations are done:
// - every back slash (\) is doubled, but only if immediately
//   followed by double quote (");
// - every double quote (") is escaped by back slash (\);
// - finally, s is wrapped with double quotes (arg -> "arg"),
//   but only if there is space or tab inside s.
func EscapeArg(s string) string { ...

So your code is ending up passing the following command line call:

$ python -c "'import pythonfile; print pythonfile.cat_strings(\\"foo\\", \\"bar\\")'"

Which, if tested, evaluates to a string and returns nothing, hence the 0-length output.