Implement range object (#87)

* Add __repr__, __str__ of range

__repr__ print start, stop of range
if step is not one, step is also printed

Fixes #86

* Add __eq__, __ne__ of range

__eq__ compare length, start, step of range

* Seperate range __repr__ for version constraint

strings.Builder is supported since v1.10,
so split files for older versions

* Add tests for range object

Author: HyeockJinKim

py/range.go

@@ -104,6 +104,14 @@ func (r *Range) M__iter__() (Object, error) {
 	}, nil
 }
 
+func (r *Range) M__str__() (Object, error) {
+	return r.M__repr__()
+}
+
+func (r *Range) M__repr__() (Object, error) {
+	return r.repr()
+}
+
 func (r *Range) M__len__() (Object, error) {
 	return r.Length, nil
 }
@@ -156,3 +164,58 @@ func computeRangeLength(start, stop, step Int) Int {
 var _ I__getitem__ = (*Range)(nil)
 var _ I__iter__ = (*Range)(nil)
 var _ I_iterator = (*RangeIterator)(nil)
+
+
+func (a *Range) M__eq__(other Object) (Object, error) {
+	b, ok := other.(*Range)
+	if !ok {
+		return NotImplemented, nil
+	}
+
+	if a.Length != b.Length {
+		return False, nil
+	}
+
+	if a.Length == 0 {
+		return True, nil
+	}
+	if a.Start != b.Start {
+		return False, nil
+	}
+
+	if a.Step == 1 {
+		return True, nil
+	}
+	if a.Step != b.Step {
+		return False, nil
+	}
+
+	return True, nil
+}
+
+func (a *Range) M__ne__(other Object) (Object, error) {
+	b, ok := other.(*Range)
+	if !ok {
+		return NotImplemented, nil
+	}
+
+	if a.Length != b.Length {
+		return True, nil
+	}
+
+	if a.Length == 0 {
+		return False, nil
+	}
+	if a.Start != b.Start {
+		return True, nil
+	}
+
+	if a.Step == 1 {
+		return False, nil
+	}
+	if a.Step != b.Step {
+		return True, nil
+	}
+
+	return False, nil
+}

py/range_repr110.go

@@ -0,0 +1,38 @@
+// Copyright 2018 The go-python Authors.  All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// +build go1.10
+// Range object
+
+package py
+
+import "strings"
+
+func (r *Range) repr() (Object, error) {
+	var b strings.Builder
+	b.WriteString("range(")
+	start, err := ReprAsString(r.Start)
+	if err != nil {
+		return nil, err
+	}
+	stop, err := ReprAsString(r.Stop)
+	if err != nil {
+		return nil, err
+	}
+	b.WriteString(start)
+	b.WriteString(", ")
+	b.WriteString(stop)
+
+	if r.Step != 1 {
+		step, err := ReprAsString(r.Step)
+		if err != nil {
+			return nil, err
+		}
+		b.WriteString(", ")
+		b.WriteString(step)
+	}
+	b.WriteString(")")
+
+	return String(b.String()), nil
+}

py/range_repr19.go

@@ -0,0 +1,38 @@
+// Copyright 2018 The go-python Authors.  All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// +build !go1.10
+// Range object
+
+package py
+
+import "bytes"
+
+func (r *Range) repr() (Object, error) {
+	var b bytes.Buffer
+	b.WriteString("range(")
+	start, err := ReprAsString(r.Start)
+	if err != nil {
+		return nil, err
+	}
+	stop, err := ReprAsString(r.Stop)
+	if err != nil {
+		return nil, err
+	}
+	b.WriteString(start)
+	b.WriteString(", ")
+	b.WriteString(stop)
+
+	if r.Step != 1 {
+		step, err := ReprAsString(r.Step)
+		if err != nil {
+			return nil, err
+		}
+		b.WriteString(", ")
+		b.WriteString(step)
+	}
+	b.WriteString(")")
+
+	return String(b.String()), nil
+}

py/tests/range.py

@@ -38,4 +38,42 @@
 assert b[-2] == 6
 assert b[-1] == 8
 
+doc="range_eq"
+assert range(10) == range(0, 10)
+assert not range(10) == 3
+assert range(20) != range(10)
+assert range(100, 200, 1) == range(100, 200)
+assert range(0, 10, 3) == range(0, 12, 3)
+assert range(2000, 100) == range(3, 1)
+assert range(0, 10, -3) == range(0, 12, -3)
+assert not range(0, 20, 2) == range(0, 20, 4)
+try:
+    range('3', 10) == range(2)
+except TypeError:
+    pass
+else:
+    assert False, "TypeError not raised"
+
+doc="range_ne"
+assert range(10, 0, -3) != range(12, 0, -3)
+assert range(10) != 3
+assert not range(100, 200, 1) != range(100, 200)
+assert range(0, 10) != range(0, 12)
+assert range(0, 10) != range(0, 10, 2)
+assert range(0, 20, 2) != range(0, 21, 2)
+assert range(0, 20, 2) != range(0, 20, 4)
+assert not range(0, 20, 3) != range(0, 20, 3)
+try:
+    range('3', 10) != range(2)
+except TypeError:
+    pass
+else:
+    assert False, "TypeError not raised"
+
+doc="range_str"
+assert str(range(10)) == 'range(0, 10)'
+assert str(range(10, 0, 3)) == 'range(10, 0, 3)'
+assert str(range(0, 3)) == 'range(0, 3)'
+assert str(range(10, 3, -2)) == 'range(10, 3, -2)'
+
 doc="finished"