diff --git a/py/internal.go b/py/internal.go
index 7c3e999a..bf654631 100644
--- a/py/internal.go
+++ b/py/internal.go
@@ -87,10 +87,21 @@ func MakeGoInt64(a Object) (int64, error) {
//
// Will raise TypeError if Index can't be run on this object
func Index(a Object) (Int, error) {
- A, ok := a.(I__index__)
- if ok {
+ if A, ok := a.(I__index__); ok {
return A.M__index__()
}
+
+ if A, ok, err := TypeCall0(a, "__index__"); ok {
+ if err != nil {
+ return 0, err
+ }
+ if res, ok := A.(Int); ok {
+ return res, nil
+ }
+
+ return 0, err
+ }
+
return 0, ExceptionNewf(TypeError, "unsupported operand type(s) for index: '%s'", a.Type().Name)
}
diff --git a/py/range.go b/py/range.go
index 31e85963..fe31497e 100644
--- a/py/range.go
+++ b/py/range.go
@@ -79,18 +79,18 @@ func RangeNew(metatype *Type, args Tuple, kwargs StringDict) (Object, error) {
}
func (r *Range) M__getitem__(key Object) (Object, error) {
+ if slice, ok := key.(*Slice); ok {
+ return computeRangeSlice(r, slice)
+ }
+
index, err := Index(key)
if err != nil {
return nil, err
}
- // TODO(corona10): Support slice case
- length := computeRangeLength(r.Start, r.Stop, r.Step)
- if index < 0 {
- index += length
- }
+ index = computeNegativeIndex(index, r.Length)
- if index < 0 || index >= length {
- return nil, ExceptionNewf(TypeError, "range object index out of range")
+ if index < 0 || index >= r.Length {
+ return nil, ExceptionNewf(IndexError, "range object index out of range")
}
result := computeItem(r, index)
return result, nil
@@ -160,6 +160,69 @@ func computeRangeLength(start, stop, step Int) Int {
return res
}
+func computeNegativeIndex(index, length Int) Int {
+ if index < 0 {
+ index += length
+ }
+ return index
+}
+
+func computeBoundIndex(index, length Int) Int {
+ if index < 0 {
+ index = 0
+ } else if index > length {
+ index = length
+ }
+ return index
+}
+
+func computeRangeSlice(r *Range, s *Slice) (Object, error) {
+ start, err := Index(s.Start)
+ if err != nil {
+ start = 0
+ }
+ stop, err := Index(s.Stop)
+ if err != nil {
+ stop = r.Length
+ }
+
+ step, err := Index(s.Step)
+ if err != nil {
+ step = 1
+ }
+ if step == 0 {
+ return nil, ExceptionNewf(ValueError, "slice step cannot be zero")
+ }
+ start = computeNegativeIndex(start, r.Length)
+ stop = computeNegativeIndex(stop, r.Length)
+
+ start = computeBoundIndex(start, r.Length)
+ stop = computeBoundIndex(stop, r.Length)
+
+ startIndex := computeItem(r, start)
+ stopIndex := computeItem(r, stop)
+ stepIndex := step * r.Step
+
+ var sliceLength Int
+ if start < stop {
+ if stepIndex < 0 {
+ startIndex, stopIndex = stopIndex-1, startIndex-1
+ }
+ } else {
+ if stepIndex < 0 {
+ startIndex, stopIndex = stopIndex+1, startIndex+1
+ }
+ }
+ sliceLength = computeRangeLength(startIndex, stopIndex, stepIndex)
+
+ return &Range{
+ Start: startIndex,
+ Stop: stopIndex,
+ Step: stepIndex,
+ Length: sliceLength,
+ }, nil
+}
+
// Check interface is satisfied
var _ I__getitem__ = (*Range)(nil)
var _ I__iter__ = (*Range)(nil)
diff --git a/py/tests/range.py b/py/tests/range.py
index 0d3a54fc..44eca5db 100644
--- a/py/tests/range.py
+++ b/py/tests/range.py
@@ -76,4 +76,44 @@
assert str(range(0, 3)) == 'range(0, 3)'
assert str(range(10, 3, -2)) == 'range(10, 3, -2)'
+doc="range_slice"
+a = range(10)
+assert a[::-1][0] == 9
+assert a[::-1][9] == 0
+assert a[0:3][0] == 0
+assert a[0:3][2] == 2
+assert a[-3:10][0] == 7
+assert a[-100:13][0] == 0
+assert a[-100:13][9] == 9
+
+try:
+ a[0:3][3]
+except IndexError:
+ pass
+else:
+ assert False, "IndexError not raised"
+try:
+ a[100:13][0]
+except IndexError:
+ pass
+else:
+ assert False, "IndexError not raised"
+try:
+ a[0:3:0]
+except ValueError:
+ pass
+else:
+ assert False, "ValueError not raised"
+
+doc="range_index"
+class Index:
+ def __index__(self):
+ return 1
+
+a = range(10)
+b = Index()
+assert a[b] == 1
+assert a[b:10] == a[1:10]
+assert a[10:b:-1] == a[10:1:-1]
+
doc="finished"
pFad - Phonifier reborn
Pfad - The Proxy pFad of © 2024 Garber Painting. All rights reserved.
Note: This service is not intended for secure transactions such as banking, social media, email, or purchasing. Use at your own risk. We assume no liability whatsoever for broken pages.
Alternative Proxies:
Alternative Proxy
pFad Proxy
pFad v3 Proxy
pFad v4 Proxy