Merge pull request beeware#525 from ivanistheone/builtin_filter

add filter builtin
indexOutOfBound5 · May 2, 2017 · dfdf402 · dfdf402
2 parents 72c7864 + 288dbab
commit dfdf402
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Showing 3 changed files with 50 additions and 43 deletions.
diff --git a/python/common/org/Python.java b/python/common/org/Python.java
@@ -674,8 +674,7 @@ public static org.python.Object exec() {
             args = {"function", "iterable"}
     )
     public static org.python.Object filter(org.python.Object function, org.python.Object iterable) {
-        org.python.Iterable iterator = org.Python.iter(iterable);
-        throw new org.python.exceptions.NotImplementedError("Builtin function 'filter' not implemented");
+        return new org.python.types.Filter(function, org.Python.iter(iterable));
     }
 
     @org.python.Method(

diff --git a/python/common/org/python/types/Filter.java b/python/common/org/python/types/Filter.java
@@ -0,0 +1,39 @@
+package org.python.types;
+
+public class Filter extends org.python.types.Object implements org.python.Iterable {
+    private org.python.Callable callable;
+    private org.python.Iterable iterator;
+
+    public Filter(org.python.Object callable, org.python.Iterable iterator) {
+        if (org.python.types.NoneType.NONE == callable) {
+            this.callable = null;
+        } else {
+            this.callable = (org.python.Callable) callable;
+        }
+        this.iterator = iterator;
+    }
+
+    @org.python.Method(
+            __doc__ = "Implement iter(self)."
+    )
+    public org.python.Iterable __iter__() {
+        return this;
+    }
+
+    @org.python.Method(
+            __doc__ = "Implement next(self)."
+    )
+    public org.python.Object __next__() {
+        while (true) {           // loop until we find first true
+            org.python.Object current = iterator.__next__();
+            org.python.Object value = current;
+            if (callable != null) {
+                org.python.Object[] args = new org.python.Object[] {current};
+                value = callable.invoke(args, new java.util.HashMap());
+            }
+            if (value.toBoolean()) {
+                return current;
+            }
+        }
+    }
+}
diff --git a/tests/builtins/test_filter.py b/tests/builtins/test_filter.py
@@ -1,53 +1,22 @@
 from .. utils import TranspileTestCase, BuiltinTwoargFunctionTestCase
 
-from unittest import expectedFailure
-
 
 class FilterTests(TranspileTestCase):
-    base_code = """
-            #placeholder while list()s etc aren't fully implemented
-            class ListLike:
-                x = %s
-                index = 0
-
-                def __iter__(self):
-                    return self
-
-                def __next__(self):
-                    self.index = self.index + 1
-                    if self.index > len(self.x):
-                        raise StopIteration
-                    return self.x[self.index]
-
-            def testish(x):
-                return %s
-
-            print(filter(testish, ListLike()))
-            mylist = ListLike()
-            print(filter(testish, mylist).__next__())
-            print(filter(testish, mylist).__next__())
-            print(filter(testish, mylist).__next__())
-            try:
-                print(filter(testish, mylist).__next__())
-            except StopIteration:
-                pass
-    """
 
-    @expectedFailure
     def test_bool(self):
-        self.assertCodeExecution(self.base_code % ("[True, False, True]", "bool(x)"))
+        self.assertCodeExecution('print(list(filter(bool, [True, False, True])))')
+        self.assertCodeExecution('print(list(filter(bool, [1, 0, 3, -1])))')
+        self.assertCodeExecution('print(list(filter(bool, [])))')
 
-    @expectedFailure
-    def test_bytearray(self):
-        self.assertCodeExecution(self.base_code % ("b'123'", "x"))
+    def test_none(self):
+        self.assertCodeExecution('print(list(filter(None, [True, False, True])))')
+        self.assertCodeExecution('print(list(filter(None, [])))')
 
-    @expectedFailure
-    def test_float(self):
-        self.assertCodeExecution(self.base_code % ("[3.14, 2.17, 1.0]", "x > 1"))
+    def test_lambda(self):
+        self.assertCodeExecution('print(list(filter(lambda x: x > 1, [3, 4, 56, 1, -11])))')
 
-    @expectedFailure
-    def test_int(self):
-        self.assertCodeExecution(self.base_code % ("[1, 2, 3]", "x * 2"))
+    def test_wrong_argument(self):
+        self.assertCodeExecution('print(list(filter(None, None)))', exits_early=True)
 
 
 class BuiltinFilterFunctionTests(BuiltinTwoargFunctionTestCase, TranspileTestCase):