Merge pull request beeware#543 from Nurdok/feature/enumerate-iterator

Implement 'enumerate' as an Iterator

batavia/builtins/enumerate.js

@@ -1,4 +1,5 @@
 var exceptions = require('../core').exceptions
+var types = require('../types')
 
 function enumerate(args, kwargs) {
  if (arguments.length !== 2) {
@@ -7,13 +8,7 @@ function enumerate(args, kwargs) {
  if (kwargs && Object.keys(kwargs).length > 0) {
  throw new exceptions.TypeError.$pyclass("enumerate() doesn't accept keyword arguments")
  }
- var result = []
- var values = args[0]
- for (var i = 0; i < values.length; i++) {
- result.push([i, values[i]])
- }
- // FIXME this should return a generator, not list
- return result
+ return new types.Enumerate(args[0])
 }
 enumerate.__doc__ = 'enumerate(iterable[, start]) -> iterator for index, value of iterable\n\nReturn an enumerate object. iterable must be another object that supports\niteration. The enumerate object yields pairs containing a count (from\nstart, which defaults to zero) and a value yielded by the iterable argument.\nenumerate is useful for obtaining an indexed list:\n (0, seq[0]), (1, seq[1]), (2, seq[2]), ...'
 

batavia/types.js

@@ -47,6 +47,8 @@ types['Slice'] = require('./types/Slice')
 
 types['CallableIterator'] = require('./types/CallableIterator')
 
+types['Enumerate'] = require('./types/Enumerate')
+
 /*************************************************************************
  * Type comparison defintions that match Python-like behavior.
  *************************************************************************/

batavia/types/Enumerate.js

@@ -0,0 +1,37 @@
+var PyObject = require('../core').Object
+var create_pyclass = require('../core').create_pyclass
+
+/**************************************************
+ * Enumerate
+ **************************************************/
+
+function Enumerate(iterable) {
+ PyObject.call(this)
+ this.iterator = iterable.__iter__([])
+ this.count = 0
+}
+
+create_pyclass(Enumerate, 'enumerate')
+
+Enumerate.prototype.__next__ = function() {
+ var item = this.iterator.__next__([])
+ var types = require('../types')
+ var index = new types.Int(this.count)
+ this.count += 1
+
+ return new types.Tuple([index, item])
+}
+
+Enumerate.prototype.__iter__ = function() {
+ return this
+}
+
+Enumerate.prototype.__str__ = function() {
+ return '<enumerate object at 0x99999999>'
+}
+
+/**************************************************
+ * Module exports
+ **************************************************/
+
+module.exports = Enumerate

tests/builtins/test_enumerate.py

@@ -2,7 +2,21 @@
 
 
 class EnumerateTests(TranspileTestCase):
- pass
+ def test_enumerate_iter(self):
+ self.assertCodeExecution("""
+ iterator = enumerate('abc')
+ print(next(iterator))
+ print(next(iterator))
+ print(next(iterator))
+ try:
+ print(next(iterator))
+ except StopIteration:
+ pass
+ try:
+ print(next(iterator))
+ except StopIteration:
+ pass
+ """)
 
 
 class BuiltinEnumerateFunctionTests(BuiltinFunctionTestCase, TranspileTestCase):
@@ -11,20 +25,11 @@ class BuiltinEnumerateFunctionTests(BuiltinFunctionTestCase, TranspileTestCase):
  not_implemented = [
  'test_noargs',
  'test_bool',
- 'test_bytearray',
- 'test_bytes',
  'test_class',
  'test_complex',
- 'test_dict',
  'test_float',
- 'test_frozenset',
  'test_int',
- 'test_list',
  'test_None',
  'test_NotImplemented',
- 'test_range',
- 'test_set',
  'test_slice',
- 'test_str',
- 'test_tuple',
  ]