py: __repr__ and __str__ for bool, bytes, dict, ellipsis, list, module, none, string, tuple

Author: ncw

py/bool.go

@@ -36,6 +36,10 @@ func (a Bool) M__index__() (Int, error) {
 }
 
 func (a Bool) M__str__() (Object, error) {
+	return a.M__repr__()
+}
+
+func (a Bool) M__repr__() (Object, error) {
 	if a {
 		return String("True"), nil
 	}
@@ -89,5 +93,6 @@ func (a Bool) M__ne__(other Object) (Object, error) {
 var _ I__bool__ = Bool(false)
 var _ I__index__ = Bool(false)
 var _ I__str__ = Bool(false)
+var _ I__repr__ = Bool(false)
 var _ I__eq__ = Bool(false)
 var _ I__ne__ = Bool(false)

py/bytes.go

@@ -4,6 +4,7 @@ package py
 
 import (
 	"bytes"
+	"fmt"
 	"strings"
 )
 
@@ -141,6 +142,45 @@ func BytesFromObject(x Object) (Bytes, error) {
 	return b, nil
 }
 
+func (a Bytes) M__str__() (Object, error) {
+	return a.M__repr__()
+}
+
+func (a Bytes) M__repr__() (Object, error) {
+	// FIXME combine this with parser/stringescape.go into file in py?
+	var out bytes.Buffer
+	quote := '\''
+	if bytes.IndexByte(a, byte('\'')) >= 0 && !(bytes.IndexByte(a, byte('"')) >= 0) {
+		quote = '"'
+	}
+	out.WriteRune('b')
+	out.WriteRune(quote)
+	for _, c := range a {
+		switch {
+		case c < 0x20:
+			switch c {
+			case '\t':
+				out.WriteString(`\t`)
+			case '\n':
+				out.WriteString(`\n`)
+			case '\r':
+				out.WriteString(`\r`)
+			default:
+				fmt.Fprintf(&out, `\x%02x`, c)
+			}
+		case c < 0x7F:
+			if c == '\\' || (quote == '\'' && c == '\'') || (quote == '"' && c == '"') {
+				out.WriteRune('\\')
+			}
+			out.WriteByte(c)
+		default:
+			fmt.Fprintf(&out, "\\x%02x", c)
+		}
+	}
+	out.WriteRune(quote)
+	return String(out.String()), nil
+}
+
 // Convert an Object to an Bytes
 //
 // Retrurns ok as to whether the conversion worked or not

py/dict.go

@@ -5,6 +5,8 @@
 
 package py
 
+import "bytes"
+
 const dictDoc = `dict() -> new empty dictionary
 dict(mapping) -> new dictionary initialized from a mapping object's
     (key, value) pairs
@@ -49,6 +51,35 @@ func (d StringDict) Copy() StringDict {
 	return e
 }
 
+func (a StringDict) M__str__() (Object, error) {
+	return a.M__repr__()
+}
+
+func (a StringDict) M__repr__() (Object, error) {
+	var out bytes.Buffer
+	out.WriteRune('{')
+	spacer := false
+	for key, value := range a {
+		if spacer {
+			out.WriteString(", ")
+		}
+		keyStr, err := ReprAsString(String(key))
+		if err != nil {
+			return nil, err
+		}
+		valueStr, err := ReprAsString(value)
+		if err != nil {
+			return nil, err
+		}
+		out.WriteString(keyStr)
+		out.WriteString(": ")
+		out.WriteString(valueStr)
+		spacer = true
+	}
+	out.WriteRune('}')
+	return String(out.String()), nil
+}
+
 func (d StringDict) M__getitem__(key Object) (Object, error) {
 	str, ok := key.(String)
 	if ok {

py/ellipsis.go

@@ -18,7 +18,7 @@ func (a EllipsisType) M__bool__() (Object, error) {
 	return False, nil
 }
 
-func (a EllipsisType) M__str__() (Object, error) {
+func (a EllipsisType) M__repr__() (Object, error) {
 	return String("Ellipsis"), nil
 }
 
@@ -38,6 +38,6 @@ func (a EllipsisType) M__ne__(other Object) (Object, error) {
 
 // Check interface is satisfied
 var _ I__bool__ = Ellipsis
-var _ I__str__ = Ellipsis
+var _ I__repr__ = Ellipsis
 var _ I__eq__ = Ellipsis
 var _ I__eq__ = Ellipsis

py/internal.go

@@ -326,52 +326,52 @@ func DeleteAttr(self Object, keyObj Object) error {
 
 // Calls __str__ on the object
 //
-// If no method was found, returns ok as false
-func str(self Object) (res Object, ok bool, err error) {
-	if _, ok = self.(String); ok {
-		return self, true, nil
+// Calls __repr__ on the object or returns a sensible default
+func Repr(self Object) (Object, error) {
+	if I, ok := self.(I__repr__); ok {
+		return I.M__repr__()
+	} else if res, ok, err := TypeCall0(self, "__repr__"); ok {
+		return res, err
 	}
+	return String(fmt.Sprintf("<%s instance at %p>", self.Type().Name, self)), nil
+}
+
+// Calls __str__ on the object and if not found calls __repr__
+func Str(self Object) (Object, error) {
 	if I, ok := self.(I__str__); ok {
-		res, err = I.M__str__()
-		return res, true, err
+		return I.M__str__()
 	} else if res, ok, err := TypeCall0(self, "__str__"); ok {
-		return res, true, err
+		return res, err
 	}
-	return nil, false, nil
+	return Repr(self)
 }
 
-// Calls __str__ on the object
-func Str(self Object) (Object, error) {
-	res, ok, err := str(self)
+// Returns object as a string
+//
+// Calls Str then makes sure the output is a string
+func StrAsString(self Object) (string, error) {
+	res, err := Str(self)
 	if err != nil {
-		return nil, err
+		return "", err
 	}
+	str, ok := res.(String)
 	if !ok {
-		return nil, ExceptionNewf(TypeError, "object of type '%s' has no __str__()", self.Type().Name)
-	}
-	return res, err
-}
-
-// Calls __repr__ on the object or returns a sensible default
-func Repr(self Object) (Object, error) {
-	if I, ok := self.(I__repr__); ok {
-		return I.M__repr__()
-	} else if res, ok, err := TypeCall0(self, "__repr__"); ok {
-		return res, err
+		return "", ExceptionNewf(TypeError, "result of __str__ must be string, not '%s'", res.Type().Name)
 	}
-	return String(fmt.Sprintf("<%s instance at %p>", self.Type().Name, self)), nil
+	return string(str), nil
 }
 
 // Returns object as a string
 //
-// Calls __str__ then __repr__ on the object then makes something up
-func AsString(self Object) (Object, error) {
-	res, ok, err := str(self)
+// Calls Repr then makes sure the output is a string
+func ReprAsString(self Object) (string, error) {
+	res, err := Repr(self)
 	if err != nil {
-		return nil, err
+		return "", err
 	}
-	if ok {
-		return res, err
+	str, ok := res.(String)
+	if !ok {
+		return "", ExceptionNewf(TypeError, "result of __repr__ must be string, not '%s'", res.Type().Name)
 	}
-	return Repr(self)
+	return string(str), nil
 }

py/list.go

@@ -92,6 +92,14 @@ func (l *List) Len() int {
 	return len(l.Items)
 }
 
+func (l *List) M__str__() (Object, error) {
+	return l.M__repr__()
+}
+
+func (l *List) M__repr__() (Object, error) {
+	return Tuple(l.Items).repr("[", "]")
+}
+
 func (l *List) M__len__() (Object, error) {
 	return Int(len(l.Items)), nil
 }
@@ -243,6 +251,8 @@ func (a *List) M__imul__(other Object) (Object, error) {
 
 // Check interface is satisfied
 var _ sequenceArithmetic = (*List)(nil)
+var _ I__str__ = (*List)(nil)
+var _ I__repr__ = (*List)(nil)
 var _ I__len__ = (*List)(nil)
 var _ I__len__ = (*List)(nil)
 var _ I__bool__ = (*List)(nil)

py/module.go

@@ -2,6 +2,8 @@
 
 package py
 
+import "fmt"
+
 var (
 	// Registry of installed modules
 	modules = make(map[string]*Module)
@@ -27,6 +29,10 @@ func (o *Module) Type() *Type {
 	return ModuleType
 }
 
+func (m *Module) M__repr__() (Object, error) {
+	return String(fmt.Sprintf("<module %s>", m.Name)), nil
+}
+
 // Get the Dict
 func (m *Module) GetDict() StringDict {
 	return m.Globals

py/none.go

@@ -20,6 +20,10 @@ func (a NoneType) M__bool__() (Object, error) {
 }
 
 func (a NoneType) M__str__() (Object, error) {
+	return a.M__repr__()
+}
+
+func (a NoneType) M__repr__() (Object, error) {
 	return String("None"), nil
 }
 
@@ -51,5 +55,6 @@ func (a NoneType) M__ne__(other Object) (Object, error) {
 // Check interface is satisfied
 var _ I__bool__ = None
 var _ I__str__ = None
+var _ I__repr__ = None
 var _ I__eq__ = None
 var _ I__ne__ = None

py/string.go

@@ -49,7 +49,7 @@ func StrNew(metatype *Type, args Tuple, kwargs StringDict) (Object, error) {
 	}
 	// FIXME ignoring encoding
 	// FIXME ignoring buffer protocol
-	return AsString(sObj)
+	return Str(sObj)
 }
 
 // Intern s possibly returning a reference to an already interned string

py/tests/bytes.py

@@ -0,0 +1,19 @@
+doc="str"
+assert str(b"") == "b''"
+assert str(b"hello") == r"b'hello'"
+assert str(rb"""hel"lo""") == r"""b'hel"lo'"""
+assert str(b"""he
+llo""") == r"""b'he\nllo'"""
+assert str(rb"""hel'lo""") == r'''b"hel'lo"'''
+assert str(b'\x00\x01\x02\x03\x04\x05\x06\x07\x08\t\n\x0b\x0c\r\x0e\x0f\x10\x11\x12\x13\x14\x15\x16\x17\x18\x19\x1a\x1b\x1c\x1d\x1e\x1f !"#$%&\'()*+,-./0123456789:;<=>?@ABCDEFGHIJKLMNOPQRSTUVWXYZ[\\]^_`abcdefghijklmnopqrstuvwxyz{|}~\x7f\x80\x81\x82\x83\x84\x85\x86\x87\x88\x89\x8a\x8b\x8c\x8d\x8e\x8f\x90\x91\x92\x93\x94\x95\x96\x97\x98\x99\x9a\x9b\x9c\x9d\x9e\x9f\xa0\xa1\xa2\xa3\xa4\xa5\xa6\xa7\xa8\xa9\xaa\xab\xac\xad\xae\xaf\xb0\xb1\xb2\xb3\xb4\xb5\xb6\xb7\xb8\xb9\xba\xbb\xbc\xbd\xbe\xbf\xc0\xc1\xc2\xc3\xc4\xc5\xc6\xc7\xc8\xc9\xca\xcb\xcc\xcd\xce\xcf\xd0\xd1\xd2\xd3\xd4\xd5\xd6\xd7\xd8\xd9\xda\xdb\xdc\xdd\xde\xdf\xe0\xe1\xe2\xe3\xe4\xe5\xe6\xe7\xe8\xe9\xea\xeb\xec\xed\xee\xef\xf0\xf1\xf2\xf3\xf4\xf5\xf6\xf7\xf8\xf9\xfa\xfb\xfc\xfd\xfe\xff') == r"""b'\x00\x01\x02\x03\x04\x05\x06\x07\x08\t\n\x0b\x0c\r\x0e\x0f\x10\x11\x12\x13\x14\x15\x16\x17\x18\x19\x1a\x1b\x1c\x1d\x1e\x1f !"#$%&\'()*+,-./0123456789:;<=>?@ABCDEFGHIJKLMNOPQRSTUVWXYZ[\\]^_`abcdefghijklmnopqrstuvwxyz{|}~\x7f\x80\x81\x82\x83\x84\x85\x86\x87\x88\x89\x8a\x8b\x8c\x8d\x8e\x8f\x90\x91\x92\x93\x94\x95\x96\x97\x98\x99\x9a\x9b\x9c\x9d\x9e\x9f\xa0\xa1\xa2\xa3\xa4\xa5\xa6\xa7\xa8\xa9\xaa\xab\xac\xad\xae\xaf\xb0\xb1\xb2\xb3\xb4\xb5\xb6\xb7\xb8\xb9\xba\xbb\xbc\xbd\xbe\xbf\xc0\xc1\xc2\xc3\xc4\xc5\xc6\xc7\xc8\xc9\xca\xcb\xcc\xcd\xce\xcf\xd0\xd1\xd2\xd3\xd4\xd5\xd6\xd7\xd8\xd9\xda\xdb\xdc\xdd\xde\xdf\xe0\xe1\xe2\xe3\xe4\xe5\xe6\xe7\xe8\xe9\xea\xeb\xec\xed\xee\xef\xf0\xf1\xf2\xf3\xf4\xf5\xf6\xf7\xf8\xf9\xfa\xfb\xfc\xfd\xfe\xff'"""
+
+doc="repr"
+assert repr(b"") == "b''"
+assert repr(b"hello") == r"b'hello'"
+assert repr(rb"""hel"lo""") == r"""b'hel"lo'"""
+assert repr(b"""he
+llo""") == r"""b'he\nllo'"""
+assert repr(rb"""hel'lo""") == r'''b"hel'lo"'''
+assert repr(b'\x00\x01\x02\x03\x04\x05\x06\x07\x08\t\n\x0b\x0c\r\x0e\x0f\x10\x11\x12\x13\x14\x15\x16\x17\x18\x19\x1a\x1b\x1c\x1d\x1e\x1f !"#$%&\'()*+,-./0123456789:;<=>?@ABCDEFGHIJKLMNOPQRSTUVWXYZ[\\]^_`abcdefghijklmnopqrstuvwxyz{|}~\x7f\x80\x81\x82\x83\x84\x85\x86\x87\x88\x89\x8a\x8b\x8c\x8d\x8e\x8f\x90\x91\x92\x93\x94\x95\x96\x97\x98\x99\x9a\x9b\x9c\x9d\x9e\x9f\xa0\xa1\xa2\xa3\xa4\xa5\xa6\xa7\xa8\xa9\xaa\xab\xac\xad\xae\xaf\xb0\xb1\xb2\xb3\xb4\xb5\xb6\xb7\xb8\xb9\xba\xbb\xbc\xbd\xbe\xbf\xc0\xc1\xc2\xc3\xc4\xc5\xc6\xc7\xc8\xc9\xca\xcb\xcc\xcd\xce\xcf\xd0\xd1\xd2\xd3\xd4\xd5\xd6\xd7\xd8\xd9\xda\xdb\xdc\xdd\xde\xdf\xe0\xe1\xe2\xe3\xe4\xe5\xe6\xe7\xe8\xe9\xea\xeb\xec\xed\xee\xef\xf0\xf1\xf2\xf3\xf4\xf5\xf6\xf7\xf8\xf9\xfa\xfb\xfc\xfd\xfe\xff') == r"""b'\x00\x01\x02\x03\x04\x05\x06\x07\x08\t\n\x0b\x0c\r\x0e\x0f\x10\x11\x12\x13\x14\x15\x16\x17\x18\x19\x1a\x1b\x1c\x1d\x1e\x1f !"#$%&\'()*+,-./0123456789:;<=>?@ABCDEFGHIJKLMNOPQRSTUVWXYZ[\\]^_`abcdefghijklmnopqrstuvwxyz{|}~\x7f\x80\x81\x82\x83\x84\x85\x86\x87\x88\x89\x8a\x8b\x8c\x8d\x8e\x8f\x90\x91\x92\x93\x94\x95\x96\x97\x98\x99\x9a\x9b\x9c\x9d\x9e\x9f\xa0\xa1\xa2\xa3\xa4\xa5\xa6\xa7\xa8\xa9\xaa\xab\xac\xad\xae\xaf\xb0\xb1\xb2\xb3\xb4\xb5\xb6\xb7\xb8\xb9\xba\xbb\xbc\xbd\xbe\xbf\xc0\xc1\xc2\xc3\xc4\xc5\xc6\xc7\xc8\xc9\xca\xcb\xcc\xcd\xce\xcf\xd0\xd1\xd2\xd3\xd4\xd5\xd6\xd7\xd8\xd9\xda\xdb\xdc\xdd\xde\xdf\xe0\xe1\xe2\xe3\xe4\xe5\xe6\xe7\xe8\xe9\xea\xeb\xec\xed\xee\xef\xf0\xf1\xf2\xf3\xf4\xf5\xf6\xf7\xf8\xf9\xfa\xfb\xfc\xfd\xfe\xff'"""
+
+doc="finished"

py/tests/dict.py

@@ -0,0 +1,11 @@
+doc="str"
+assert str({}) == "{}"
+a = str({"a":"b","c":5.5})
+assert a == "{'a': 'b', 'c': 5.5}" or a == "{'c': 5.5, 'a': 'b'}"
+
+doc="repr"
+assert repr({}) == "{}"
+a = repr({"a":"b","c":5.5})
+assert a == "{'a': 'b', 'c': 5.5}" or a == "{'c': 5.5, 'a': 'b'}"
+
+doc="finished"

py/tests/list.py

@@ -0,0 +1,13 @@
+doc="str"
+assert str([]) == "[]"
+assert str([1,2,3]) == "[1, 2, 3]"
+assert str([1,[2,3],4]) == "[1, [2, 3], 4]"
+assert str(["1",[2.5,17,[]]]) == "['1', [2.5, 17, []]]"
+
+doc="repr"
+assert repr([]) == "[]"
+assert repr([1,2,3]) == "[1, 2, 3]"
+assert repr([1,[2,3],4]) == "[1, [2, 3], 4]"
+assert repr(["1",[2.5,17,[]]]) == "['1', [2.5, 17, []]]"
+
+doc="finished"

py/tests/tuple.py

@@ -0,0 +1,13 @@
+doc="str"
+assert str(()) == "()"
+assert str((1,2,3)) == "(1, 2, 3)"
+assert str((1,(2,3),4)) == "(1, (2, 3), 4)"
+assert str(("1",(2.5,17,()))) == "('1', (2.5, 17, ()))"
+
+doc="repr"
+assert repr(()) == "()"
+assert repr((1,2,3)) == "(1, 2, 3)"
+assert repr((1,(2,3),4)) == "(1, (2, 3), 4)"
+assert repr(("1",(2.5,17,()))) == "('1', (2.5, 17, ()))"
+
+doc="finished"