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 +186,43 @@ func builtin_print(self py.Object, args py.Tuple, kwargs py.StringDict) (py.Obje
 	}
 	sep := sepObj.(py.String)
 	end := endObj.(py.String)
-	// FIXME ignoring file and flush
+
+	write, err := py.GetAttrString(file, "write")
+	if err != nil {
+		return nil, err
+	}
+
 	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 {
+			return py.Call(fflush, nil, nil)
+		}
+	}
+
 	return py.None, nil
 }
 

builtin/tests/builtin.py

@@ -147,9 +147,42 @@ 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:
+    #if e.args[0] != "'int' object has no attribute 'write'":
+    #   raise
+    ok = True
+assert ok, "AttributeError not raised"
+
+with open("testfile", "w") as f:
+    print("hello", "world", sep=" ", end="\n", file=f)
+
+with open("testfile", "r") as f:
+    assert f.read() == "hello world\n"
+
+with open("testfile", "w") as f:
+    print(1,2,3,sep=",",end=",\n", file=f)
+
+with open("testfile", "r") as f:
+    assert f.read() == "1,2,3,\n"
 
 doc="round"
 assert round(1.1) == 1.0

py/file.go

@@ -16,6 +16,7 @@ import (
 )
 
 var FileType = NewType("file", `represents an open file`)
+var errClosed = ExceptionNewf(ValueError, "I/O operation on closed file.")
 
 func init() {
 	FileType.Dict["write"] = MustNewMethod("write", func(self Object, value Object) (Object, error) {
@@ -28,6 +29,9 @@ 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
@@ -71,6 +75,9 @@ func (o *File) Write(value Object) (Object, error) {
 	}
 
 	n, err := o.File.Write(b)
+	if err != nil && err.(*os.PathError).Err == os.ErrClosed {
+		return nil, errClosed
+	}
 	return Int(n), err
 }
 
@@ -123,10 +130,14 @@ func (o *File) Read(args Tuple, kwargs StringDict) (Object, error) {
 	}
 
 	b, err := ioutil.ReadAll(r)
-	if err == io.EOF {
-		return o.readResult(nil)
-	}
 	if err != nil {
+		if err == io.EOF {
+			return o.readResult(nil)
+		}
+		if perr, ok := err.(*os.PathError); ok && perr.Err == os.ErrClosed {
+			return nil, errClosed
+		}
+
 		return nil, err
 	}
 
@@ -138,6 +149,23 @@ func (o *File) Close() (Object, error) {
 	return None, nil
 }
 
+func (o *File) Flush() (Object, error) {
+	err := o.File.Sync()
+	if perr, ok := err.(*os.PathError); ok && perr.Err == os.ErrClosed {
+		return nil, errClosed
+	}
+
+	return None, nil
+}
+
+func (o *File) M__enter__() (Object, error) {
+	return o, nil
+}
+
+func (o *File) M__exit__(exc_type, exc_value, traceback Object) (Object, error) {
+	return o.Close()
+}
+
 func OpenFile(filename, mode string, buffering int) (Object, error) {
 	var fileMode FileMode
 	var truncate bool
@@ -177,8 +205,8 @@ 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 {
@@ -229,14 +257,15 @@ func OpenFile(filename, mode string, buffering int) (Object, error) {
 
 	f, err := os.OpenFile(filename, fmode, 0666)
 	if err != nil {
-		// XXX: should check for different types of errors
 		switch {
 		case os.IsExist(err):
 			return nil, ExceptionNewf(FileExistsError, err.Error())
 
 		case os.IsNotExist(err):
 			return nil, ExceptionNewf(FileNotFoundError, err.Error())
 		}
+
+		return nil, ExceptionNewf(OSError, err.Error())
 	}
 
 	if finfo, err := f.Stat(); err == nil {
@@ -250,3 +279,5 @@ func OpenFile(filename, mode string, buffering int) (Object, error) {
 }
 
 // Check interface is satisfied
+var _ I__enter__ = (*File)(nil)
+var _ I__exit__ = (*File)(nil)

py/tests/file.py

@@ -35,9 +35,13 @@
 assert n == 5
 
 doc = "close"
-f.close()
+assert f.close() == None
+
+assertRaises(ValueError, f.read, 1)
+assertRaises(ValueError, f.write, "")
+assertRaises(ValueError, f.flush)
 
 # closing a closed file should not throw an error
-f.close()
+assert f.close() == None
 
 doc = "finished"

pytest/pytest.go

@@ -12,7 +12,6 @@ import (
 	"testing"
 
 	_ "github.com/go-python/gpython/builtin"
-	_ "github.com/go-python/gpython/sys"
 	"github.com/go-python/gpython/compile"
 	"github.com/go-python/gpython/py"
 	_ "github.com/go-python/gpython/sys"