all: use cpkg to print via C-stdio so outputs are sync'd with python's i/o layer

Change-Id: If1dfa6e3cbb74cf4cd4852ea6db850c3318b388b

_examples/cpkg/cpkg.go

@@ -7,7 +7,7 @@ package cpkg
 //#include <stdio.h>
 //#include <string.h>
 //#include <stdlib.h>
-//void hello(const char *str) {
+//void cpkg_printf(const char *str) {
 //	fprintf(stdout, str);
 //}
 import "C"
@@ -17,12 +17,27 @@ import (
 	"unsafe"
 )
 
+// Hi prints hi from Go (via C's stdio)
+func Hi() {
+	cstr := C.CString("hi from go\n")
+	defer C.free(unsafe.Pointer(cstr))
+	C.cpkg_printf(cstr)
+}
+
 // Hello prints a string via C's stdio
 func Hello(s string) {
 	if s == "" {
 		s = "you"
 	}
-	cstr := C.CString(fmt.Sprintf("hello %s from C\n", s))
+	cstr := C.CString(fmt.Sprintf("hello %s from go\n", s))
 	defer C.free(unsafe.Pointer(cstr))
-	C.hello(cstr)
+	C.cpkg_printf(cstr)
+}
+
+// Printf prints a string via C's stdio
+func Printf(format string, args ...interface{}) {
+	str := fmt.Sprintf(format, args...)
+	cstr := C.CString(str)
+	defer C.free(unsafe.Pointer(cstr))
+	C.cpkg_printf(cstr)
 }

_examples/hi/hi.go

@@ -7,6 +7,8 @@ package hi
 
 import (
 	"fmt"
+
+	"github.com/go-python/gopy/_examples/cpkg"
 )
 
 const (
@@ -23,12 +25,12 @@ var (
 
 // Hi prints hi from Go
 func Hi() {
-	fmt.Printf("hi from go\n")
+	cpkg.Hi()
 }
 
 // Hello prints a greeting from Go
 func Hello(s string) {
-	fmt.Printf("hello %s from go\n", s)
+	cpkg.Hello(s)
 }
 
 // Concat concatenates two strings together and returns the resulting string.
@@ -86,11 +88,11 @@ func (p *Person) greet() string {
 
 // Work makes a Person go to work for h hours
 func (p *Person) Work(h int) error {
-	fmt.Printf("working...\n")
+	cpkg.Printf("working...\n")
 	if h > 7 {
 		return fmt.Errorf("can't work for %d hours!", h)
 	}
-	fmt.Printf("worked for %d hours\n", h)
+	cpkg.Printf("worked for %d hours\n", h)
 	return nil
 }
 

main_test.go

@@ -49,14 +49,7 @@ func TestBind(t *testing.T) {
 		t.Fatalf("error copying 'test.py': %v\n", err)
 	}
 
-	want := []byte(`hi from go
+	want := []byte(`--- doc(hi)...
-hello you from go
-working...
-worked for 2 hours
-working...
-working...
-worked for 4 hours
---- doc(hi)...
 package hi exposes a few Go functions to be wrapped and used from Python.
 
 --- hi.GetUniverse(): 42
@@ -76,12 +69,14 @@ Hi()
 Hi prints hi from Go
 
 --- hi.Hi()...
+hi from go
 --- doc(hi.Hello)...
 Hello(str s) 
 
 Hello prints a greeting from Go
 
 --- hi.Hello('you')...
+hello you from go
 --- doc(hi.Add)...
 Add(int i, int j) int
 
@@ -118,14 +113,19 @@ hi.Person{Name="foo", Age=42}
 --- p.Age: 42
 --- p.Name: foo
 --- p.Work(2)...
+working...
+worked for 2 hours
 --- p.Work(24)...
+working...
 caught: can't work for 24 hours!
 --- p.Salary(2): 20
 --- p.Salary(24): caught: can't work for 24 hours!
 caught: Person.__init__ takes no argument | err-type: <type 'exceptions.TypeError'>
 --- hi.NewPerson('me', 666): hi.Person{Name="me", Age=666}
 --- hi.NewPersonWithAge(666): hi.Person{Name="stranger", Age=666}
---- hi.NewActivePerson(4): hi.Person{Name="", Age=0}
+--- hi.NewActivePerson(4):working...
+worked for 4 hours
+ hi.Person{Name="", Age=0}
 --- c = hi.Couple()...
 hi.Couple{P1=hi.Person{Name="", Age=0}, P2=hi.Person{Name="", Age=0}}
 --- c.P1: hi.Person{Name="", Age=0}