Add support for print to file and file flush.

Author: raff

builtin/builtin.go

@@ -6,7 +6,6 @@
 package builtin
 
 import (
-	"fmt"
 	"unicode/utf8"
 
 	"github.com/go-python/gpython/compile"
@@ -177,7 +176,7 @@ func builtin_print(self py.Object, args py.Tuple, kwargs py.StringDict) (py.Obje
 	var (
 		sepObj py.Object = py.String(" ")
 		endObj py.Object = py.String("\n")
-		file   py.Object
+		file   py.Object = py.MustGetModule("sys").Globals["stdout"]
 		flush  py.Object
 	)
 	kwlist := []string{"sep", "end", "file", "flush"}
@@ -187,19 +186,44 @@ func builtin_print(self py.Object, args py.Tuple, kwargs py.StringDict) (py.Obje
 	}
 	sep := sepObj.(py.String)
 	end := endObj.(py.String)
+
+	write, err := py.GetAttrString(file, "write")
+	if err != nil {
+		return nil, err
+	}
+
 	// FIXME ignoring file and flush
 	for i, v := range args {
 		v, err := py.Str(v)
 		if err != nil {
 			return nil, err
 		}
 
-		fmt.Printf("%v", v)
+		_, err = py.Call(write, py.Tuple{v}, nil)
+		if err != nil {
+			return nil, err
+		}
+
 		if i != len(args)-1 {
-			fmt.Print(sep)
+			_, err = py.Call(write, py.Tuple{sep}, nil)
+			if err != nil {
+				return nil, err
+			}
 		}
 	}
-	fmt.Print(end)
+
+	_, err = py.Call(write, py.Tuple{end}, nil)
+	if err != nil {
+		return nil, err
+	}
+
+	if shouldFlush, _ := py.MakeBool(flush); shouldFlush == py.True {
+		fflush, err := py.GetAttrString(file, "flush")
+		if err == nil {
+			py.Call(fflush, nil, nil)
+		}
+	}
+
 	return py.None, nil
 }
 

builtin/tests/builtin.py

@@ -147,9 +147,47 @@ def gen2():
 assert repr("hello") == "'hello'"
 
 doc="print"
-# FIXME - need io redirection to test
-#print("hello world")
-#print(1,2,3,sep=",",end=",\n")
+ok = False
+try:
+    print("hello", sep=1)
+except TypeError as e:
+    #if e.args[0] != "sep must be None or a string, not int":
+    #   raise
+    ok = True
+assert ok, "TypeError not raised"
+
+try:
+    print("hello", sep=" ", end=1)
+except TypeError as e:
+    #if e.args[0] != "end must be None or a string, not int":
+    #   raise
+    ok = True
+assert ok, "TypeError not raised"
+
+try:
+    print("hello", sep=" ", end="\n", file=1)
+except AttributeError as e:
+    print(e.args[0])
+    #if e.args[0] != "'int' object has no attribute 'write'":
+    #   raise
+    ok = True
+assert ok, "AttributeError not raised"
+
+f = open("testfile", "w")
+print("hello", "world", sep=" ", end="\n", file=f)
+assert f.close() is None
+
+f = open("testfile", "r")
+assert f.read() == "hello world\n"
+assert f.close() is None
+
+f = open("testfile", "w")
+print(1,2,3,sep=",",end=",\n", file=f)
+assert f.close() is None
+
+f= open("testfile", "r")
+assert f.read() == "1,2,3,\n"
+assert f.close() is None
 
 doc="round"
 assert round(1.1) == 1.0

py/file.go

@@ -28,6 +28,9 @@ func init() {
 	FileType.Dict["close"] = MustNewMethod("close", func(self Object) (Object, error) {
 		return self.(*File).Close()
 	}, 0, "close() -> None or (perhaps) an integer.  Close the file.\n\nSets data attribute .closed to True.  A closed file cannot be used for\nfurther I/O operations.  close() may be called more than once without\nerror.  Some kinds of file objects (for example, opened by popen())\nmay return an exit status upon closing.")
+	FileType.Dict["flush"] = MustNewMethod("flush", func(self Object) (Object, error) {
+		return self.(*File).Flush()
+	}, 0, "flush() -> Flush the write buffers of the stream if applicable. This does nothing for read-only and non-blocking streams.")
 }
 
 type FileMode int
@@ -138,6 +141,16 @@ func (o *File) Close() (Object, error) {
 	return None, nil
 }
 
+func (o *File) Flush() (Object, error) {
+	_ = o.File.Sync()
+	return None, nil
+}
+
+func (o *File) M__exit__(exc_type, exc_value, traceback Object) (Object, error) {
+	o.Close()
+	return None, nil
+}
+
 func OpenFile(filename, mode string, buffering int) (Object, error) {
 	var fileMode FileMode
 	var truncate bool
@@ -177,8 +190,8 @@ func OpenFile(filename, mode string, buffering int) (Object, error) {
 				return nil, ExceptionNewf(ValueError, "Must have exactly one of create/read/write/append mode and at most one plus")
 			}
 
+			truncate = (fileMode & FileWrite) != 0
 			fileMode |= FileReadWrite
-			truncate = false
 
 		case 'b':
 			if fileMode&FileReadWrite == 0 {
@@ -250,3 +263,4 @@ func OpenFile(filename, mode string, buffering int) (Object, error) {
 }
 
 // Check interface is satisfied
+var _ I__exit__ = (*File)(nil)