add `itertools` (#239)

docs/modules/itertools.md

@@ -0,0 +1,7 @@
+---
+icon: package
+label: itertools
+---
+
+### `itertools.zip_longest(a, b)`
+

python/itertools.py

@@ -0,0 +1,13 @@
+def zip_longest(a, b):
+    a = iter(a)
+    b = iter(b)
+    while True:
+        ai = next(a)
+        bi = next(b)
+        if ai is StopIteration and bi is StopIteration:
+            break
+        if ai is StopIteration:
+            ai = None
+        if bi is StopIteration:
+            bi = None
+        yield ai, bi

src/pocketpy.cpp

@@ -1606,6 +1606,7 @@ void VM::post_init(){
     _lazy_modules["typing"] = kPythonLibs_typing;
     _lazy_modules["datetime"] = kPythonLibs_datetime;
     _lazy_modules["cmath"] = kPythonLibs_cmath;
+    _lazy_modules["itertools"] = kPythonLibs_itertools;
 
     try{
         CodeObject_ code = compile(kPythonLibs_builtins, "<builtins>", EXEC_MODE);

tests/86_itertools.py

@@ -0,0 +1,6 @@
+from itertools import zip_longest
+
+a = [1, 2, 3]
+b = [2]
+
+assert list(zip_longest(a, b)) == [(1, 2), (2, None), (3, None)]