enum.py compiles and loads

5 files changed, 1480 insertions, 107 deletions

diff --git a/modules/language/python/compile.scm b/modules/language/python/compile.scm
index 170cb11..0b3b872 100644
--- a/modules/language/python/compile.scm
+++ b/modules/language/python/compile.scm
@@ -41,6 +41,11 @@
 (define-inlinable (H   x) `(@  (language python hash)    ,x))
 (define-inlinable (W   x) `(@  (language python with)    ,x))
 
+(define-syntax-rule (use a ...)
+  (catch #t
+    (lambda () (use-modules a ...))
+    (lambda x (raise (ImportError '(a ...))))))
+
 (define s/d 'set!)
 
 (define (pre) (warn "Patching guile will lead to way better experience use 'python.patch' on guile-2.2 e.g. (use-modules (language python guilemod))"))
@@ -119,8 +124,13 @@
   (match e
     (#f item)
     ((#:cfor for-e in-e cont)
-     `(,(F 'for) ((,@(map (g vs exp) for-e) : ,(exp vs in-e))) ()
-       ,(gen-sel vs cont item)))
+     (let lp ((for-e for-e))
+       (match for-e
+         (((#:power #f (#:tuple . l) . _))
+          (lp l))
+         (_
+          `(,(F 'for) ((,@(map (g vs exp) for-e) : ,(exp vs in-e))) ()
+            ,(gen-sel vs cont item))))))
     ((#:cif cif cont)
      `(if ,(exp vs cif)          
           ,(gen-sel vs cont item)))))
@@ -217,6 +227,23 @@
                   '()              
                   l)
             vs))
+
+    ((#:expr-stmt l (#:assign k . u))
+     (union
+      (union (fold (lambda (x s)
+                     (match x
+                       ((#:test (#:power v2 v1 () . _) . _)
+                        (if v2
+                            (union
+                             (union (list (exp '() v1))
+                                    (list (exp '() v2)))
+                             s)
+                            (union (list (exp '() v1)) s)))
+                       (_ s)))
+                   '()              
+                   l)
+             vs)
+      (scope `(#:expr-stmt ,k (#:asignvs . ,u)) vs)))
     
     ((x . y)
      (scope y (scope x vs)))
@@ -425,11 +452,17 @@
       (()
        '()))))
 
-(define (get-args_ vs arg)
+(define (getarg x)
+  (match x
+    ((#:tp x . l)
+     x)
+    (x x)))
+
+(define (get-args_ vs arg)  
   (let lp ((arg arg))
     (match arg
       (((#:arg x) . arg)
-       (cons (exp vs (car x))
+       (cons (exp vs (getarg x))
              (lp arg)))
       ((x . args)
        (lp args))
@@ -441,7 +474,7 @@
   (let lp ((arg arg))
     (match arg
       (((#:= x v) . arg)
-       (cons (list '= (exp vs (car x)) (exp vs v))
+       (cons (list '= (exp vs (getarg x)) (exp vs v))
              (lp arg)))
       
       ((x . args)
@@ -454,7 +487,7 @@
   (let lp ((arg arg))
     (match arg
       (((#:* x) . arg)
-       (cons (list '* (exp vs (car x)))
+       (cons (list '* (exp vs (getarg x)))
              (lp arg)))
 
       ((x . args)
@@ -467,7 +500,7 @@
   (let lp ((arg arg))
     (match arg
       (((#:** x) . arg)
-       (cons (list '** (exp vs (car x)))
+       (cons (list '** (exp vs (getarg x)))
              (lp arg)))
 
       ((x . args)
@@ -570,6 +603,7 @@
       ("//="  'floor-quotient)))
   
   (match x
+    ((#:verb x) x)
     ((#:test (#:power kind v addings . _) . _)
      (let* ((v       (exp vs v))
             (v.add   (if (is-prefix? v)
@@ -661,6 +695,18 @@
                    
     ...))
 
+(define (tr-comp op x y)
+  (match op
+    ((or "<" ">" "<=" ">=")
+     (list (G (string->symbol op)) x y))
+    ("!="    (list (G 'not) (list (O 'equal?) x y)))
+    ("=="    (list (O 'equal?) x y))
+    ("is"    (list (G 'eq?) x y))
+    ("isnot" (list (G 'not) (list (G 'eq?)    x y)))
+    ("in"    (list (L 'in) x y))
+    ("notin" (list (G 'not) (list (L 'in)     x y)))
+    ("<>"    (list (G 'not) (list (O 'equal?) x y)))))
+
 (gen-table x vs
  (#:power
   ((_ _ (x) () . #f)
@@ -869,7 +915,7 @@
                      `(,(G 'cons) '() '()))
                 ,(map (lambda (x) `(define ,x #f)) ls)
                 ,(exp vs code))))))))))
-(#:verb
+ (#:verb
   ((_ x) x))
  
  (#:scm
@@ -877,17 +923,17 @@
  
  (#:import
   ((_ (#:from (() . nm) . #f))
-   `(use-modules (language python module ,@(map (lambda (nm) (exp vs nm))
+   `(,(C 'use) (language python module ,@(map (lambda (nm) (exp vs nm))
 						nm))))
-  ((_ (#:from (() . nm) . l))
-   `(use-modules ((language python module ,@(map (lambda (nm) (exp vs nm))
+  ((_ (#:from (() . nm)  l))
+   `(,(C 'use)  ((language python module ,@(map (lambda (nm) (exp vs nm))
 						 nm))
-		  #:select ,(map (lambda (x)
-				   (match x
-					  ((a . #f)
-					   (exp vs a))
-					  ((a . b)
-					   (cons (exp vs a) (exp vs b)))))
+                 #:select ,(map (lambda (x)
+                                  (match x
+                                    ((a . #f)
+                                     (exp vs a))
+                                    ((a . b)
+                                     (cons (exp vs a) (exp vs b)))))
 				 l))))
 					      
   
@@ -923,71 +969,80 @@
  (#:for
   ((_ e in code . #f)
    (=> next)
-   (match e
-     (((#:power #f (#:identifier x . _) () . #f))
-      (match in
-        (((#:test power . _))
-         (match power
-           ((#:power #f
-                     (#:identifier "range" . _)
-                     ((#:arglist arglist . _))
-                     . _)
-            (match arglist
-              ((arg)
-               (let ((v   (gensym "v"))
-                     (x   (string->symbol x))
-                     (lp  (gensym "lp")))
-                 `(let ((,v ,(exp vs arg)))
-                    (let ,lp ((,x 0))
-                         (if (< ,x ,v)
-                             (begin
-                               ,(exp vs code)
-                               (,lp (+ ,x 1))))))))
-              ((arg1 arg2)
-               (let ((v1   (gensym "va"))
-                     (v2   (gensym "vb"))
-                     (lp  (gensym "lp")))
-                 `(let ((,v1 ,(exp vs arg1))
-                        (,v2 ,(exp vs arg2)))
-                    (let ,lp ((,x ,v1))
-                         (if (< ,x ,v2)
-                             (begin
-                               ,(exp vs code)
-                               (,lp (+ ,x 1))))))))
-              ((arg1 arg2 arg3)
-               (let ((v1   (gensym "va"))
-                     (v2   (gensym "vb"))
-                     (st   (gensym "vs"))
-                     (lp  (gensym "lp")))
-                 `(let ((,v1 ,(exp vs arg1))
-                        (,st ,(exp vs arg2))
-                        (,v2 ,(exp vs arg3)))
-                    (if (> st 0)
-                        (let ,lp ((,x ,v1))
-                             (if (< ,x ,v2)
-                                 (begin
-                                   ,(exp vs code)
-                                   (,lp (+ ,x ,st)))))
-                        (if (< st 0)
-                            (let ,lp ((,x ,v1))
-                                 (if (> ,x ,v2)
-                                     (begin
-                                       ,(exp vs code)
-                                       (,lp (+ ,x ,st)))))
-                            (error "range with step 0 not allowed"))))))
-              (_ (next))))
-           (_ (next))))
-        (_ (next))))
-     (_ (next))))
+   (let lp ((e e))
+     (match e
+       (((#:power #f (#:tuple . l) . _))
+        (lp l))
+       
+       (((#:power #f (#:identifier x . _) () . #f))
+        (match in
+          (((#:test power . _))
+           (match power
+             ((#:power #f
+                       (#:identifier "range" . _)
+                       ((#:arglist arglist . _))
+                       . _)
+              (match arglist
+                ((arg)
+                 (let ((v   (gensym "v"))
+                       (x   (string->symbol x))
+                       (lp  (gensym "lp")))
+                   `(let ((,v ,(exp vs arg)))
+                      (let ,lp ((,x 0))
+                           (if (< ,x ,v)
+                               (begin
+                                 ,(exp vs code)
+                                 (,lp (+ ,x 1))))))))
+                ((arg1 arg2)
+                 (let ((v1   (gensym "va"))
+                       (v2   (gensym "vb"))
+                       (lp  (gensym "lp")))
+                   `(let ((,v1 ,(exp vs arg1))
+                          (,v2 ,(exp vs arg2)))
+                      (let ,lp ((,x ,v1))
+                           (if (< ,x ,v2)
+                               (begin
+                                 ,(exp vs code)
+                                 (,lp (+ ,x 1))))))))
+                ((arg1 arg2 arg3)
+                 (let ((v1   (gensym "va"))
+                       (v2   (gensym "vb"))
+                       (st   (gensym "vs"))
+                       (lp  (gensym "lp")))
+                   `(let ((,v1 ,(exp vs arg1))
+                          (,st ,(exp vs arg2))
+                          (,v2 ,(exp vs arg3)))
+                      (if (> st 0)
+                          (let ,lp ((,x ,v1))
+                               (if (< ,x ,v2)
+                                   (begin
+                                     ,(exp vs code)
+                                     (,lp (+ ,x ,st)))))
+                          (if (< st 0)
+                              (let ,lp ((,x ,v1))
+                                   (if (> ,x ,v2)
+                                       (begin
+                                         ,(exp vs code)
+                                         (,lp (+ ,x ,st)))))
+                              (error "range with step 0 not allowed"))))))
+                (_ (next))))
+             (_ (next))))
+          (_ (next))))
+       (_ (next)))))
   
   ((_ es in code . else)
-   (let* ((es2   (map (g vs exp) es))
-          (vs2   (union es2 vs))
-          (code2 (exp vs2 code))
-          (p     (is-ec #t code2 #t (list (C 'break) (C 'continue))))
-          (else2 (if else (exp vs2 else) #f))
-          (in2   (map (g vs exp) in)))
-     (list (C 'cfor) es2 in2 code2 else2 p))))
+   (let lp ((es es))
+     (match es
+       (((#:power #f (#:tuple . l) . _))
+        (lp l))
+       (_            
+        (let* ((es2   (map (g vs exp) es))
+               (vs2   (union es2 vs))
+               (code2 (exp vs2 code))
+               (p     (is-ec #t code2 #t (list (C 'break) (C 'continue))))
+               (else2 (if else (exp vs2 else) #f))
+               (in2   (map (g vs exp) in)))
+          (list (C 'cfor) es2 in2 code2 else2 p)))))))
  
 
  (#:while
@@ -1016,11 +1071,11 @@
     
     
   ((_ x exc else . fin)
-   `(,(T 'try) ,(exp vs x)
+   `(,(T 'try) (lambda () ,(exp vs x))
      ,@(let lp ((exc exc) (r (if else (exp vs else) '())))
          (match exc
            ((((test . #f) code) . exc)
-            (lp exc (cons `(#:except ,(exp vs code)) r)))
+            (lp exc (cons `(#:except ,(exp vs test) ,(exp vs code)) r)))
 
 	   (((#f code) . exc)
             (lp exc (cons `(#:except ,(exp vs code)) r)))
@@ -1075,7 +1130,7 @@
          (set! ,(C 'inhibit-finally) #t)
          (let ((,g (,f ,@(gen-yargs vs args))))
            (,g))))))
-  
+ 
  (#:def
   ((_ f
       (#:types-args-list . args)
@@ -1199,8 +1254,12 @@
         `(cons ,(exp vs x) ,(lp l)))))))
  
  (#:lambdef
-  ((_ v e)
-   (list `lambda v (exp vs e))))
+  ((_ (#:var-args-list . v) e)
+   (let ((as (get-args_  vs v))
+         (a= (get-args=  vs v))
+         (a* (get-args*  vs v))
+         (** (get-args** vs v)))         
+     (list (C `lam) `(,@as ,@a* ,@a= ,@**) (exp vs e)))))
  
  (#:stmt
   ((_ l)
@@ -1214,7 +1273,12 @@
      (if (= (length l) 1)
 	 (car l)
 	 `(,(G 'values) ,@l))))
-   
+
+  ((_ l (#:assign x y . u))
+   (let ((z (gensym "x")))
+     `(let ((,x ,(exp vs `(#:expr-stmt1 ((#:verb ,z)) (#:assign ,y . ,u)))))
+        ,(exp vs `(#:expr-stmt ,x (#:assign ((#:verb ,z))))))))
+  
   ((_ l type)
    (=> fail)
    (call-with-values
@@ -1273,6 +1337,61 @@
                                      x)))
         (,(C 'raise) ,(C 'AssertionError) ',f ,n ,m))))
 
+
+  
+ (#:expr-stmt1
+  ((_ l (#:assign x y . u))
+   (let ((z (gensym "x")))
+     `(let ((,x ,(exp vs `(#:expr-stmt1 ((#:verb ,z))
+                                        (#:assign ,y . ,u)))))
+        ,(exp vs `(#:expr-stmt ,x (#:assign ((#:verb ,z))))))))
+  
+  ((_ l type)
+   (=> fail)
+   (call-with-values
+       (lambda () (match type
+                    ((#:assign u)
+                      (values #f u))
+                    ((#:augassign op u)
+                     (values op u))
+                    (_ (fail))))
+      
+     (lambda (op u)
+       (cond
+        ((= (length l) (length u))
+         (if (= (length l) 1)
+             `(begin
+                ,(make-set vs op (car l) (exp vs (car u)))
+                ,(exp vs (car l)))
+             `(begin
+                @,(map (lambda (l u) (make-set vs op l u))
+                       l
+                       (map (g vs exp) u))
+                (values ,@(map (g exp vs) l)))))
+        
+        ((and (= (length u) 1) (not op))         
+         (let ((vars (map (lambda (x) (gensym "v")) l))
+               (q    (gensym "q"))
+               (f    (gensym "f")))
+           `(begin
+              (call-with-values (lambda () ,(exp vs (car u)))
+                (letrec ((,f
+                          (case-lambda
+                            ((,q)
+                             (if (pair? ,q)
+                                 (apply ,f ,q)
+                                 (apply ,f (,(L 'to-list) ,q))))
+                            (,vars
+                             ,@(map (lambda (l v) (make-set vs op l v))
+                                    l vars)))))
+                  ,f))
+              (values ,@(map (g exp vs) l)))))
+        
+        ((and (= (length l) 1) (not op))
+         `(begin
+            ,(make-set vs op (car l) `(,(G 'list) ,@(map (g vs exp) u)))
+            (values ,(exp vs (car l))))))))))
+  
  (#:return
   ((_  x)
    (if x
@@ -1318,18 +1437,14 @@
    (exp vs x))
 
   ((_ x (op . y))
-   (define (tr op x y)
-     (match op
-       ((or "<" ">" "<=" ">=")
-        (list (G (string->symbol op)) x y))
-       ("!="    (list (G 'not) (list (O 'equal?) x y)))
-       ("=="    (list (O 'equal?) x y))
-       ("is"    (list (G 'eq?) x y))
-       ("isnot" (list (G 'not) (list (G 'eq?)    x y)))
-       ("in"    (list (L 'in) x y))
-       ("notin" (list (G 'not) (list (L 'in)     x y)))
-       ("<>"    (list (G 'not) (list (O 'equal?) x y)))))
-   (tr op (exp vs x) (exp vs y)))))
+   (tr-comp op (exp vs x) (exp vs y)))
+
+  ((_ x (op . y) . l)
+   (let ((m (gensym "op")))
+     `(let ((,m ,(exp vs y)))
+        (and ,(tr-comp op (exp vs x) m)
+             ,(exp vs `(#:comp (#:verb ,m) . ,l))))))))
+
 
 (define (exp vs x)
   (match (pr x)
@@ -1372,7 +1487,8 @@
                 arglist))
 
          `((,(G 'define-module) (language python module ,@args)
-            #:use-module (language python module python))
+            #:use-module (language python module python)
+            #:use-module (language python exceptions))
            (define __doc__    #f)
            (define __module__ '(language python module ,@args)))))
       (x '())))
@@ -1936,6 +2052,8 @@
 (define (export-all)
   (define mod (current-module))
   (if (module-defined? mod '__all__)
-      (for ((x : (module-ref mod '__all__))) ()
-           (module-export! mod (string->symbol (scm-str x))))))
+      (module-export! mod
+         (for ((x : (module-ref mod '__all__))) ((l '()))
+              (cons (string->symbol (scm-str x)) l)
+              #:final l))))
   
diff --git a/modules/language/python/exceptions.scm b/modules/language/python/exceptions.scm
index 99e8b97..93ce54d 100644
--- a/modules/language/python/exceptions.scm
+++ b/modules/language/python/exceptions.scm
@@ -7,7 +7,7 @@
                           SyntaxError SystemException
                           OSError ProcessLookupError PermissionError
                           None NotImplemented NotImplementedError
-			  RunTimeError AssertionError
+			  RunTimeError AssertionError ImportError
                           ModuleNotFoundError BlockingIOError))
 
 (define-syntax-rule (aif it p x y) (let ((it p)) (if it x y)))
@@ -28,8 +28,12 @@
            (format #f "~a"
                    (ref self '__name__))))))
 
-(define-syntax-rule (define-er nm k)
-  (define-python-class nm (Exception)))
+(define-syntax define-er
+  (syntax-rules ()
+    ((_ nm k)
+     (define-python-class nm (Exception)))
+    ((_ nm w k)
+     (define-python-class nm w))))
 
 (define StopIteration          'StopIteration)
 (define GeneratorExit          'GeneratorExit)
@@ -48,7 +52,8 @@
 (define-er NotImplementedError 'NotImplementedError)
 (define-er RunTimeError        'RunTimeError)
 (define AssertionError         'AssertionError)
-(define-er ModuleNotFoundError 'ModuleNotFoundError)
+(define-er ImportError         'ImportError)      
+(define-er ModuleNotFoundError (ImportError) 'ModuleNotFoundError)
 (define-er BlockingIOError     'BlockingIOError)
 
 (define NotImplemented (list 'NotImplemented))
diff --git a/modules/language/python/module/enum.py b/modules/language/python/module/enum.py
new file mode 100644
index 0000000..4f388ad
--- /dev/null
+++ b/modules/language/python/module/enum.py
@@ -0,0 +1,876 @@
+module(enum) ## needed in guile atm
+
+import sys
+from types import MappingProxyType, DynamicClassAttribute
+from functools import reduce
+from operator import or_ as _or_
+
+# try _collections first to reduce startup cost
+try:
+    from _collections import OrderedDict
+except ImportError:
+    from collections import OrderedDict
+
+
+__all__ = [
+        'EnumMeta',
+        'Enum', 'IntEnum', 'Flag', 'IntFlag',
+        'auto', 'unique',
+        ]
+
+
+def _is_descriptor(obj):
+    """Returns True if obj is a descriptor, False otherwise."""
+    return (
+            hasattr(obj, '__get__') or
+            hasattr(obj, '__set__') or
+            hasattr(obj, '__delete__'))
+
+
+def _is_dunder(name):
+    """Returns True if a __dunder__ name, False otherwise."""
+    return (name[:2] == name[-2:] == '__' and
+            name[2:3] != '_' and
+            name[-3:-2] != '_' and
+            len(name) > 4)
+
+
+def _is_sunder(name):
+    """Returns True if a _sunder_ name, False otherwise."""
+    return (name[0] == name[-1] == '_' and
+            name[1:2] != '_' and
+            name[-2:-1] != '_' and
+            len(name) > 2)
+
+def _make_class_unpicklable(cls):
+    """Make the given class un-picklable."""
+    def _break_on_call_reduce(self, proto):
+        raise TypeError('%r cannot be pickled' % self)
+    cls.__reduce_ex__ = _break_on_call_reduce
+    cls.__module__ = '<unknown>'
+
+_auto_null = object()
+class auto:
+    """
+    Instances are replaced with an appropriate value in Enum class suites.
+    """
+    value = _auto_null
+
+
+class _EnumDict(dict):
+    """Track enum member order and ensure member names are not reused.
+
+    EnumMeta will use the names found in self._member_names as the
+    enumeration member names.
+
+    """
+    def __init__(self):
+        super().__init__()
+        self._member_names = []
+        self._last_values = []
+
+    def __setitem__(self, key, value):
+        """Changes anything not dundered or not a descriptor.
+
+        If an enum member name is used twice, an error is raised; duplicate
+        values are not checked for.
+
+        Single underscore (sunder) names are reserved.
+
+        """
+        if _is_sunder(key):
+            if key not in (
+                    '_order_', '_create_pseudo_member_',
+                    '_generate_next_value_', '_missing_',
+                    ):
+                raise ValueError('_names_ are reserved for future Enum use')
+            if key == '_generate_next_value_':
+                setattr(self, '_generate_next_value', value)
+        elif _is_dunder(key):
+            if key == '__order__':
+                key = '_order_'
+        elif key in self._member_names:
+            # descriptor overwriting an enum?
+            raise TypeError('Attempted to reuse key: %r' % key)
+        elif not _is_descriptor(value):
+            if key in self:
+                # enum overwriting a descriptor?
+                raise TypeError('%r already defined as: %r' % (key, self[key]))
+            if isinstance(value, auto):
+                if value.value == _auto_null:
+                    value.value = self._generate_next_value(key, 1, len(self._member_names), self._last_values[:])
+                value = value.value
+            self._member_names.append(key)
+            self._last_values.append(value)
+        super().__setitem__(key, value)
+
+
+# Dummy value for Enum as EnumMeta explicitly checks for it, but of course
+# until EnumMeta finishes running the first time the Enum class doesn't exist.
+# This is also why there are checks in EnumMeta like `if Enum is not None`
+Enum = None
+
+
+class EnumMeta(type):
+    """Metaclass for Enum"""
+    @classmethod
+    def __prepare__(metacls, cls, bases):
+        # create the namespace dict
+        enum_dict = _EnumDict()
+        # inherit previous flags and _generate_next_value_ function
+        member_type, first_enum = metacls._get_mixins_(bases)
+        if first_enum is not None:
+            enum_dict['_generate_next_value_'] = getattr(first_enum, '_generate_next_value_', None)
+        return enum_dict
+
+    def __new__(metacls, cls, bases, classdict):
+        # an Enum class is final once enumeration items have been defined; it
+        # cannot be mixed with other types (int, float, etc.) if it has an
+        # inherited __new__ unless a new __new__ is defined (or the resulting
+        # class will fail).
+        member_type, first_enum = metacls._get_mixins_(bases)
+        __new__, save_new, use_args = metacls._find_new_(classdict, member_type,
+                                                        first_enum)
+
+        # save enum items into separate mapping so they don't get baked into
+        # the new class
+        enum_members = {k: classdict[k] for k in classdict._member_names}
+        for name in classdict._member_names:
+            del classdict[name]
+
+        # adjust the sunders
+        _order_ = classdict.pop('_order_', None)
+
+        # check for illegal enum names (any others?)
+        invalid_names = set(enum_members) & {'mro', }
+        if invalid_names:
+            raise ValueError('Invalid enum member name: {0}'.format(
+                ','.join(invalid_names)))
+
+        # create a default docstring if one has not been provided
+        if '__doc__' not in classdict:
+            classdict['__doc__'] = 'An enumeration.'
+
+        # create our new Enum type
+        enum_class = super().__new__(metacls, cls, bases, classdict)
+        enum_class._member_names_ = []               # names in definition order
+        enum_class._member_map_ = OrderedDict()      # name->value map
+        enum_class._member_type_ = member_type
+
+        # save attributes from super classes so we know if we can take
+        # the shortcut of storing members in the class dict
+        base_attributes = {a for b in enum_class.mro() for a in b.__dict__}
+
+        # Reverse value->name map for hashable values.
+        enum_class._value2member_map_ = {}
+
+        # If a custom type is mixed into the Enum, and it does not know how
+        # to pickle itself, pickle.dumps will succeed but pickle.loads will
+        # fail.  Rather than have the error show up later and possibly far
+        # from the source, sabotage the pickle protocol for this class so
+        # that pickle.dumps also fails.
+        #
+        # However, if the new class implements its own __reduce_ex__, do not
+        # sabotage -- it's on them to make sure it works correctly.  We use
+        # __reduce_ex__ instead of any of the others as it is preferred by
+        # pickle over __reduce__, and it handles all pickle protocols.
+        if '__reduce_ex__' not in classdict:
+            if member_type is not object:
+                methods = ('__getnewargs_ex__', '__getnewargs__',
+                        '__reduce_ex__', '__reduce__')
+                if not any(m in member_type.__dict__ for m in methods):
+                    _make_class_unpicklable(enum_class)
+
+        # instantiate them, checking for duplicates as we go
+        # we instantiate first instead of checking for duplicates first in case
+        # a custom __new__ is doing something funky with the values -- such as
+        # auto-numbering ;)
+        for member_name in classdict._member_names:
+            value = enum_members[member_name]
+            if not isinstance(value, tuple):
+                args = (value, )
+            else:
+                args = value
+            if member_type is tuple:   # special case for tuple enums
+                args = (args, )     # wrap it one more time
+            if not use_args:
+                enum_member = __new__(enum_class)
+                if not hasattr(enum_member, '_value_'):
+                    enum_member._value_ = value
+            else:
+                enum_member = __new__(enum_class, *args)
+                if not hasattr(enum_member, '_value_'):
+                    if member_type is object:
+                        enum_member._value_ = value
+                    else:
+                        enum_member._value_ = member_type(*args)
+            value = enum_member._value_
+            enum_member._name_ = member_name
+            enum_member.__objclass__ = enum_class
+            enum_member.__init__(*args)
+            # If another member with the same value was already defined, the
+            # new member becomes an alias to the existing one.
+            for name, canonical_member in enum_class._member_map_.items():
+                if canonical_member._value_ == enum_member._value_:
+                    enum_member = canonical_member
+                    break
+            else:
+                # Aliases don't appear in member names (only in __members__).
+                enum_class._member_names_.append(member_name)
+            # performance boost for any member that would not shadow
+            # a DynamicClassAttribute
+            if member_name not in base_attributes:
+                setattr(enum_class, member_name, enum_member)
+            # now add to _member_map_
+            enum_class._member_map_[member_name] = enum_member
+            try:
+                # This may fail if value is not hashable. We can't add the value
+                # to the map, and by-value lookups for this value will be
+                # linear.
+                enum_class._value2member_map_[value] = enum_member
+            except TypeError:
+                pass
+
+        # double check that repr and friends are not the mixin's or various
+        # things break (such as pickle)
+        for name in ('__repr__', '__str__', '__format__', '__reduce_ex__'):
+            class_method = getattr(enum_class, name)
+            obj_method = getattr(member_type, name, None)
+            enum_method = getattr(first_enum, name, None)
+            if obj_method is not None and obj_method is class_method:
+                setattr(enum_class, name, enum_method)
+
+        # replace any other __new__ with our own (as long as Enum is not None,
+        # anyway) -- again, this is to support pickle
+        if Enum is not None:
+            # if the user defined their own __new__, save it before it gets
+            # clobbered in case they subclass later
+            if save_new:
+                enum_class.__new_member__ = __new__
+            enum_class.__new__ = Enum.__new__
+
+        # py3 support for definition order (helps keep py2/py3 code in sync)
+        if _order_ is not None:
+            if isinstance(_order_, str):
+                _order_ = _order_.replace(',', ' ').split()
+            if _order_ != enum_class._member_names_:
+                raise TypeError('member order does not match _order_')
+
+        return enum_class
+
+    def __bool__(self):
+        """
+        classes/types should always be True.
+        """
+        return True
+
+    def __call__(cls, value, names=None, *, module=None, qualname=None, type=None, start=1):
+        """Either returns an existing member, or creates a new enum class.
+
+        This method is used both when an enum class is given a value to match
+        to an enumeration member (i.e. Color(3)) and for the functional API
+        (i.e. Color = Enum('Color', names='RED GREEN BLUE')).
+
+        When used for the functional API:
+
+        `value` will be the name of the new class.
+
+        `names` should be either a string of white-space/comma delimited names
+        (values will start at `start`), or an iterator/mapping of name, value pairs.
+
+        `module` should be set to the module this class is being created in;
+        if it is not set, an attempt to find that module will be made, but if
+        it fails the class will not be picklable.
+
+        `qualname` should be set to the actual location this class can be found
+        at in its module; by default it is set to the global scope.  If this is
+        not correct, unpickling will fail in some circumstances.
+
+        `type`, if set, will be mixed in as the first base class.
+
+        """
+        if names is None:  # simple value lookup
+            return cls.__new__(cls, value)
+        # otherwise, functional API: we're creating a new Enum type
+        return cls._create_(value, names, module=module, qualname=qualname, type=type, start=start)
+
+    def __contains__(cls, member):
+        return isinstance(member, cls) and member._name_ in cls._member_map_
+
+    def __delattr__(cls, attr):
+        # nicer error message when someone tries to delete an attribute
+        # (see issue19025).
+        if attr in cls._member_map_:
+            raise AttributeError(
+                    "%s: cannot delete Enum member." % cls.__name__)
+        super().__delattr__(attr)
+
+    def __dir__(self):
+        return (['__class__', '__doc__', '__members__', '__module__'] +
+                self._member_names_)
+
+    def __getattr__(cls, name):
+        """Return the enum member matching `name`
+
+        We use __getattr__ instead of descriptors or inserting into the enum
+        class' __dict__ in order to support `name` and `value` being both
+        properties for enum members (which live in the class' __dict__) and
+        enum members themselves.
+
+        """
+        if _is_dunder(name):
+            raise AttributeError(name)
+        try:
+            return cls._member_map_[name]
+        except KeyError:
+            raise AttributeError(name) from None
+
+    def __getitem__(cls, name):
+        return cls._member_map_[name]
+
+    def __iter__(cls):
+        return (cls._member_map_[name] for name in cls._member_names_)
+
+    def __len__(cls):
+        return len(cls._member_names_)
+
+    @property
+    def __members__(cls):
+        """Returns a mapping of member name->value.
+
+        This mapping lists all enum members, including aliases. Note that this
+        is a read-only view of the internal mapping.
+
+        """
+        return MappingProxyType(cls._member_map_)
+
+    def __repr__(cls):
+        return "<enum %r>" % cls.__name__
+
+    def __reversed__(cls):
+        return (cls._member_map_[name] for name in reversed(cls._member_names_))
+
+    def __setattr__(cls, name, value):
+        """Block attempts to reassign Enum members.
+
+        A simple assignment to the class namespace only changes one of the
+        several possible ways to get an Enum member from the Enum class,
+        resulting in an inconsistent Enumeration.
+
+        """
+        member_map = cls.__dict__.get('_member_map_', {})
+        if name in member_map:
+            raise AttributeError('Cannot reassign members.')
+        super().__setattr__(name, value)
+
+    def _create_(cls, class_name, names=None, *, module=None, qualname=None, type=None, start=1):
+        """Convenience method to create a new Enum class.
+
+        `names` can be:
+
+        * A string containing member names, separated either with spaces or
+          commas.  Values are incremented by 1 from `start`.
+        * An iterable of member names.  Values are incremented by 1 from `start`.
+        * An iterable of (member name, value) pairs.
+        * A mapping of member name -> value pairs.
+
+        """
+        metacls = cls.__class__
+        bases = (cls, ) if type is None else (type, cls)
+        _, first_enum = cls._get_mixins_(bases)
+        classdict = metacls.__prepare__(class_name, bases)
+
+        # special processing needed for names?
+        if isinstance(names, str):
+            names = names.replace(',', ' ').split()
+        if isinstance(names, (tuple, list)) and names and isinstance(names[0], str):
+            original_names, names = names, []
+            last_values = []
+            for count, name in enumerate(original_names):
+                value = first_enum._generate_next_value_(name, start, count, last_values[:])
+                last_values.append(value)
+                names.append((name, value))
+
+        # Here, names is either an iterable of (name, value) or a mapping.
+        for item in names:
+            if isinstance(item, str):
+                member_name, member_value = item, names[item]
+            else:
+                member_name, member_value = item
+            classdict[member_name] = member_value
+        enum_class = metacls.__new__(metacls, class_name, bases, classdict)
+
+        # TODO: replace the frame hack if a blessed way to know the calling
+        # module is ever developed
+        if module is None:
+            try:
+                module = sys._getframe(2).f_globals['__name__']
+            except (AttributeError, ValueError) as exc:
+                pass
+        if module is None:
+            _make_class_unpicklable(enum_class)
+        else:
+            enum_class.__module__ = module
+        if qualname is not None:
+            enum_class.__qualname__ = qualname
+
+        return enum_class
+
+    @staticmethod
+    def _get_mixins_(bases):
+        """Returns the type for creating enum members, and the first inherited
+        enum class.
+
+        bases: the tuple of bases that was given to __new__
+
+        """
+        if not bases:
+            return object, Enum
+
+        # double check that we are not subclassing a class with existing
+        # enumeration members; while we're at it, see if any other data
+        # type has been mixed in so we can use the correct __new__
+        member_type = first_enum = None
+        for base in bases:
+            if  (base is not Enum and
+                    issubclass(base, Enum) and
+                    base._member_names_):
+                raise TypeError("Cannot extend enumerations")
+        # base is now the last base in bases
+        if not issubclass(base, Enum):
+            raise TypeError("new enumerations must be created as "
+                    "`ClassName([mixin_type,] enum_type)`")
+
+        # get correct mix-in type (either mix-in type of Enum subclass, or
+        # first base if last base is Enum)
+        if not issubclass(bases[0], Enum):
+            member_type = bases[0]     # first data type
+            first_enum = bases[-1]  # enum type
+        else:
+            for base in bases[0].__mro__:
+                # most common: (IntEnum, int, Enum, object)
+                # possible:    (<Enum 'AutoIntEnum'>, <Enum 'IntEnum'>,
+                #               <class 'int'>, <Enum 'Enum'>,
+                #               <class 'object'>)
+                if issubclass(base, Enum):
+                    if first_enum is None:
+                        first_enum = base
+                else:
+                    if member_type is None:
+                        member_type = base
+
+        return member_type, first_enum
+
+    @staticmethod
+    def _find_new_(classdict, member_type, first_enum):
+        """Returns the __new__ to be used for creating the enum members.
+
+        classdict: the class dictionary given to __new__
+        member_type: the data type whose __new__ will be used by default
+        first_enum: enumeration to check for an overriding __new__
+
+        """
+        # now find the correct __new__, checking to see of one was defined
+        # by the user; also check earlier enum classes in case a __new__ was
+        # saved as __new_member__
+        __new__ = classdict.get('__new__', None)
+
+        # should __new__ be saved as __new_member__ later?
+        save_new = __new__ is not None
+
+        if __new__ is None:
+            # check all possibles for __new_member__ before falling back to
+            # __new__
+            for method in ('__new_member__', '__new__'):
+                for possible in (member_type, first_enum):
+                    target = getattr(possible, method, None)
+                    if target not in {
+                            None,
+                            None.__new__,
+                            object.__new__,
+                            Enum.__new__,
+                            }:
+                        __new__ = target
+                        break
+                if __new__ is not None:
+                    break
+            else:
+                __new__ = object.__new__
+
+        # if a non-object.__new__ is used then whatever value/tuple was
+        # assigned to the enum member name will be passed to __new__ and to the
+        # new enum member's __init__
+        if __new__ is object.__new__:
+            use_args = False
+        else:
+            use_args = True
+
+        return __new__, save_new, use_args
+
+class Enum(metaclass=EnumMeta):
+    """Generic enumeration.
+
+    Derive from this class to define new enumerations.
+
+    """
+    def __new__(cls, value):
+        # all enum instances are actually created during class construction
+        # without calling this method; this method is called by the metaclass'
+        # __call__ (i.e. Color(3) ), and by pickle
+        if type(value) is cls:
+            # For lookups like Color(Color.RED)
+            return value
+        # by-value search for a matching enum member
+        # see if it's in the reverse mapping (for hashable values)
+        try:
+            if value in cls._value2member_map_:
+                return cls._value2member_map_[value]
+        except TypeError:
+            # not there, now do long search -- O(n) behavior
+            for member in cls._member_map_.values():
+                if member._value_ == value:
+                    return member
+        # still not found -- try _missing_ hook
+        return cls._missing_(value)
+
+    def _generate_next_value_(name, start, count, last_values):
+        for last_value in reversed(last_values):
+            try:
+                return last_value + 1
+            except TypeError:
+                pass
+        else:
+            return start
+
+    @classmethod
+    def _missing_(cls, value):
+        raise ValueError("%r is not a valid %s" % (value, cls.__name__))
+
+    def __repr__(self):
+        return "<%s.%s: %r>" % (
+                self.__class__.__name__, self._name_, self._value_)
+
+    def __str__(self):
+        return "%s.%s" % (self.__class__.__name__, self._name_)
+
+    def __dir__(self):
+        added_behavior = [
+                m
+                for cls in self.__class__.mro()
+                for m in cls.__dict__
+                if m[0] != '_' and m not in self._member_map_
+                ]
+        return (['__class__', '__doc__', '__module__'] + added_behavior)
+
+    def __format__(self, format_spec):
+        # mixed-in Enums should use the mixed-in type's __format__, otherwise
+        # we can get strange results with the Enum name showing up instead of
+        # the value
+
+        # pure Enum branch
+        if self._member_type_ is object:
+            cls = str
+            val = str(self)
+        # mix-in branch
+        else:
+            cls = self._member_type_
+            val = self._value_
+        return cls.__format__(val, format_spec)
+
+    def __hash__(self):
+        return hash(self._name_)
+
+    def __reduce_ex__(self, proto):
+        return self.__class__, (self._value_, )
+
+    # DynamicClassAttribute is used to provide access to the `name` and
+    # `value` properties of enum members while keeping some measure of
+    # protection from modification, while still allowing for an enumeration
+    # to have members named `name` and `value`.  This works because enumeration
+    # members are not set directly on the enum class -- __getattr__ is
+    # used to look them up.
+
+    @DynamicClassAttribute
+    def name(self):
+        """The name of the Enum member."""
+        return self._name_
+
+    @DynamicClassAttribute
+    def value(self):
+        """The value of the Enum member."""
+        return self._value_
+
+    @classmethod
+    def _convert(cls, name, module, filter, source=None):
+        """
+        Create a new Enum subclass that replaces a collection of global constants
+        """
+        # convert all constants from source (or module) that pass filter() to
+        # a new Enum called name, and export the enum and its members back to
+        # module;
+        # also, replace the __reduce_ex__ method so unpickling works in
+        # previous Python versions
+        module_globals = vars(sys.modules[module])
+        if source:
+            source = vars(source)
+        else:
+            source = module_globals
+        # We use an OrderedDict of sorted source keys so that the
+        # _value2member_map is populated in the same order every time
+        # for a consistent reverse mapping of number to name when there
+        # are multiple names for the same number rather than varying
+        # between runs due to hash randomization of the module dictionary.
+        members = [
+                (name, source[name])
+                for name in source.keys()
+                if filter(name)]
+        try:
+            # sort by value
+            members.sort(key=lambda t: (t[1], t[0]))
+        except TypeError:
+            # unless some values aren't comparable, in which case sort by name
+            members.sort(key=lambda t: t[0])
+        cls = cls(name, members, module=module)
+        cls.__reduce_ex__ = _reduce_ex_by_name
+        module_globals.update(cls.__members__)
+        module_globals[name] = cls
+        return cls
+
+
+class IntEnum(int, Enum):
+    """Enum where members are also (and must be) ints"""
+
+
+def _reduce_ex_by_name(self, proto):
+    return self.name
+
+class Flag(Enum):
+    """Support for flags"""
+
+    def _generate_next_value_(name, start, count, last_values):
+        """
+        Generate the next value when not given.
+
+        name: the name of the member
+        start: the initital start value or None
+        count: the number of existing members
+        last_value: the last value assigned or None
+        """
+        if not count:
+            return start if start is not None else 1
+        for last_value in reversed(last_values):
+            try:
+                high_bit = _high_bit(last_value)
+                break
+            except Exception:
+                raise TypeError('Invalid Flag value: %r' % last_value) from None
+        return 2 ** (high_bit+1)
+
+    @classmethod
+    def _missing_(cls, value):
+        original_value = value
+        if value < 0:
+            value = ~value
+        possible_member = cls._create_pseudo_member_(value)
+        if original_value < 0:
+            possible_member = ~possible_member
+        return possible_member
+
+    @classmethod
+    def _create_pseudo_member_(cls, value):
+        """
+        Create a composite member iff value contains only members.
+        """
+        pseudo_member = cls._value2member_map_.get(value, None)
+        if pseudo_member is None:
+            # verify all bits are accounted for
+            _, extra_flags = _decompose(cls, value)
+            if extra_flags:
+                raise ValueError("%r is not a valid %s" % (value, cls.__name__))
+            # construct a singleton enum pseudo-member
+            pseudo_member = object.__new__(cls)
+            pseudo_member._name_ = None
+            pseudo_member._value_ = value
+            # use setdefault in case another thread already created a composite
+            # with this value
+            pseudo_member = cls._value2member_map_.setdefault(value, pseudo_member)
+        return pseudo_member
+
+    def __contains__(self, other):
+        if not isinstance(other, self.__class__):
+            return NotImplemented
+        return other._value_ & self._value_ == other._value_
+
+    def __repr__(self):
+        cls = self.__class__
+        if self._name_ is not None:
+            return '<%s.%s: %r>' % (cls.__name__, self._name_, self._value_)
+        members, uncovered = _decompose(cls, self._value_)
+        return '<%s.%s: %r>' % (
+                cls.__name__,
+                '|'.join([str(m._name_ or m._value_) for m in members]),
+                self._value_,
+                )
+
+    def __str__(self):
+        cls = self.__class__
+        if self._name_ is not None:
+            return '%s.%s' % (cls.__name__, self._name_)
+        members, uncovered = _decompose(cls, self._value_)
+        if len(members) == 1 and members[0]._name_ is None:
+            return '%s.%r' % (cls.__name__, members[0]._value_)
+        else:
+            return '%s.%s' % (
+                    cls.__name__,
+                    '|'.join([str(m._name_ or m._value_) for m in members]),
+                    )
+
+    def __bool__(self):
+        return bool(self._value_)
+
+    def __or__(self, other):
+        if not isinstance(other, self.__class__):
+            return NotImplemented
+        return self.__class__(self._value_ | other._value_)
+
+    def __and__(self, other):
+        if not isinstance(other, self.__class__):
+            return NotImplemented
+        return self.__class__(self._value_ & other._value_)
+
+    def __xor__(self, other):
+        if not isinstance(other, self.__class__):
+            return NotImplemented
+        return self.__class__(self._value_ ^ other._value_)
+
+    def __invert__(self):
+        members, uncovered = _decompose(self.__class__, self._value_)
+        inverted_members = [
+                m for m in self.__class__
+                if m not in members and not m._value_ & self._value_
+                ]
+        inverted = reduce(_or_, inverted_members, self.__class__(0))
+        return self.__class__(inverted)
+
+
+class IntFlag(int, Flag):
+    """Support for integer-based Flags"""
+
+    @classmethod
+    def _missing_(cls, value):
+        if not isinstance(value, int):
+            raise ValueError("%r is not a valid %s" % (value, cls.__name__))
+        new_member = cls._create_pseudo_member_(value)
+        return new_member
+
+    @classmethod
+    def _create_pseudo_member_(cls, value):
+        pseudo_member = cls._value2member_map_.get(value, None)
+        if pseudo_member is None:
+            need_to_create = [value]
+            # get unaccounted for bits
+            _, extra_flags = _decompose(cls, value)
+            # timer = 10
+            while extra_flags:
+                # timer -= 1
+                bit = _high_bit(extra_flags)
+                flag_value = 2 ** bit
+                if (flag_value not in cls._value2member_map_ and
+                        flag_value not in need_to_create
+                        ):
+                    need_to_create.append(flag_value)
+                if extra_flags == -flag_value:
+                    extra_flags = 0
+                else:
+                    extra_flags ^= flag_value
+            for value in reversed(need_to_create):
+                # construct singleton pseudo-members
+                pseudo_member = int.__new__(cls, value)
+                pseudo_member._name_ = None
+                pseudo_member._value_ = value
+                # use setdefault in case another thread already created a composite
+                # with this value
+                pseudo_member = cls._value2member_map_.setdefault(value, pseudo_member)
+        return pseudo_member
+
+    def __or__(self, other):
+        if not isinstance(other, (self.__class__, int)):
+            return NotImplemented
+        result = self.__class__(self._value_ | self.__class__(other)._value_)
+        return result
+
+    def __and__(self, other):
+        if not isinstance(other, (self.__class__, int)):
+            return NotImplemented
+        return self.__class__(self._value_ & self.__class__(other)._value_)
+
+    def __xor__(self, other):
+        if not isinstance(other, (self.__class__, int)):
+            return NotImplemented
+        return self.__class__(self._value_ ^ self.__class__(other)._value_)
+
+    __ror__ = __or__
+    __rand__ = __and__
+    __rxor__ = __xor__
+
+    def __invert__(self):
+        result = self.__class__(~self._value_)
+        return result
+
+
+def _high_bit(value):
+    """returns index of highest bit, or -1 if value is zero or negative"""
+    return value.bit_length() - 1
+
+def unique(enumeration):
+    """Class decorator for enumerations ensuring unique member values."""
+    duplicates = []
+    for name, member in enumeration.__members__.items():
+        if name != member.name:
+            duplicates.append((name, member.name))
+    if duplicates:
+        alias_details = ', '.join(
+                ["%s -> %s" % (alias, name) for (alias, name) in duplicates])
+        raise ValueError('duplicate values found in %r: %s' %
+                (enumeration, alias_details))
+    return enumeration
+
+def _decompose(flag, value):
+    """Extract all members from the value."""
+    # _decompose is only called if the value is not named
+    not_covered = value
+    negative = value < 0
+    # issue29167: wrap accesses to _value2member_map_ in a list to avoid race
+    #             conditions between iterating over it and having more psuedo-
+    #             members added to it
+    if negative:
+        # only check for named flags
+        flags_to_check = [
+                (m, v)
+                for v, m in list(flag._value2member_map_.items())
+                if m.name is not None
+                ]
+    else:
+        # check for named flags and powers-of-two flags
+        flags_to_check = [
+                (m, v)
+                for v, m in list(flag._value2member_map_.items())
+                if m.name is not None or _power_of_two(v)
+                ]
+    members = []
+    for member, member_value in flags_to_check:
+        if member_value and member_value & value == member_value:
+            members.append(member)
+            not_covered &= ~member_value
+    if not members and value in flag._value2member_map_:
+        members.append(flag._value2member_map_[value])
+    members.sort(key=lambda m: m._value_, reverse=True)
+    if len(members) > 1 and members[0].value == value:
+        # we have the breakdown, don't need the value member itself
+        members.pop(0)
+    return members, not_covered
+
+def _power_of_two(value):
+    if value < 1:
+        return False
+    return value == 2 ** _high_bit(value)
diff --git a/modules/language/python/module/io.scm b/modules/language/python/module/io.scm
index dceced8..87a2ec8 100644
--- a/modules/language/python/module/io.scm
+++ b/modules/language/python/module/io.scm
@@ -411,8 +411,13 @@
       (set self 'raw raw)))
 
   (define peek
-    (lambda (self)
-      (raise UnsupportedOperation peek))))
+    (lambda* (self #:optional (size 1))
+      (check (self port)
+        (list->string
+         (let ((r (peek-char port)))
+           (if (char? r)
+               (list r)
+               (list))))))))
 
 (define-python-class BufferedWriter (BufferedIOBase)
   (define __init__
diff --git a/modules/language/python/module/types.scm b/modules/language/python/module/types.scm
new file mode 100644
index 0000000..840b901
--- /dev/null
+++ b/modules/language/python/module/types.scm
@@ -0,0 +1,369 @@
+(define-module (language python module types)
+  #:use-module (oop goops)
+  #:use-module (oop pf-objects)
+  #:use-module (language python exceptions)
+  #:use-module (language python def)
+  #:use-module (language python bool)
+  #:use-module ((language python module python)
+                 #:select (getattr type))
+  #:export (MappingProxyType DynamicClassAttribute Functiontype LambdaType))
+  
+"""
+Define names for built-in types that aren't directly accessible as a builtin.
+"""
+(define MappingProxyType       <hashtable>)
+(define FunctionType           <procedure>)
+(define LambdaType             <procedure>)
+
+(define-python-class  DynamicClassAttribute ()
+  "Route attribute access on a class to __getattr__.
+
+  This is a descriptor, used to define attributes that act differently when
+  accessed through an instance and through a class.  Instance access remains
+  normal, but access to an attribute through a class will be routed to the
+  class's __getattr__ method; this is done by raising AttributeError.
+
+  This allows one to have properties active on an instance, and have virtual
+  attributes on the class with the same name (see Enum for an example).
+  "
+  
+  (define __init__
+    (lam (self (= fget None) (= fset None) (= fdel None) (= doc None))
+         (set self 'fget fget)
+         (set self 'fset fset)
+         (set self 'fdel fdel)
+         
+         ;; next two lines make DynamicClassAttribute act the same as property
+         (set self '__doc__ (or (bool doc) (ref fget '__doc__)))
+         (set self 'overwrite_doc  (eq? doc  None))
+         
+         ;; support for abstract methods
+         (set self '__isabstractmethod__
+              (bool (getattr fget '__isabstractmethod__' #f)))))
+
+  (define __get__
+    (lam (self instance (= ownerclass None))
+         (cond
+          ((eq? instance None)
+           (if (bool (ref self '__isabstractmethod__))
+               self
+               (raise (AttributeError))))
+          ((eq? (ref self 'fget) None)
+           (raise (AttributeError "unreadable attribute")))
+          (else
+           ((ref self 'fget) instance)))))
+
+  (define __set__
+    (lambda (self instance value)
+      (if (eq? (ref self 'fset) None)
+          (raise (AttributeError "can't set attribute"))
+          ((ref self 'fset) instance value))))
+
+  (define __delete__
+    (lambda (self instance)
+      (if (eq? (ref self 'fdel) None)
+          (raise (AttributeError "can't delete attribute"))
+          ((ref self 'fdel) instance))))
+
+  (define getter
+    (lambda (self fget)
+      (let* ((fdoc (if (ref self 'overwrite_doc)
+                       (ref fget '__doc__)
+                       None))
+             (result ((type self)
+                      fget
+                      (ref self 'fset)
+                      (ref self 'fdel)
+                      (or (bool fdoc) (ref self '__doc__)))))
+        
+        (set result 'overwrite_doc (ref self 'overwrite_doc))
+        result)))
+
+  (define setter
+    (lambda (self fset)
+      (let ((result ((type self)
+                     (ref self 'fget)
+                     fset
+                     (ref self 'fdel)
+                     (ref self '__doc__))))
+        
+        (set result 'overwrite_doc (ref self 'overwrite_doc))
+        result)))
+  
+  (define deleter
+    (lambda (self fdel)
+      (let ((result ((type self)
+                     (ref self 'fget)
+                     (ref self 'fset)
+                     fdel
+                     (ref self '__doc__))))
+        
+        (set result 'overwrite_doc (ref self 'overwrite_doc))
+        result))))
+
+#|
+import sys
+
+# Iterators in Python aren't a matter of type but of protocol.  A large
+# and changing number of builtin types implement *some* flavor of
+# iterator.  Don't check the type!  Use hasattr to check for both
+# "__iter__" and "__next__" attributes instead.
+
+def _f(): pass
+FunctionType = type(_f)
+LambdaType = type(lambda: None)         # Same as FunctionType
+MappingProxyType = type(type.__dict__)
+CodeType = type(_f.__code__)
+
+SimpleNamespace = type(sys.implementation)
+
+def _g():
+   yield 1
+GeneratorType = type(_g())
+
+async def _c(): pass
+_c = _c()
+CoroutineType = type(_c)
+_c.close()  # Prevent ResourceWarning
+
+async def _ag():
+    yield
+_ag = _ag()
+AsyncGeneratorType = type(_ag)
+
+class _C:
+    def _m(self): pass
+MethodType = type(_C()._m)
+
+BuiltinFunctionType = type(len)
+BuiltinMethodType = type([].append)     # Same as BuiltinFunctionType
+
+ModuleType = type(sys)
+
+try:
+    raise TypeError
+except TypeError:
+    tb = sys.exc_info()[2]
+    TracebackType = type(tb)
+    FrameType = type(tb.tb_frame)
+    tb = None; del tb
+
+# For Jython, the following two types are identical
+GetSetDescriptorType = type(FunctionType.__code__)
+MemberDescriptorType = type(FunctionType.__globals__)
+
+del sys, _f, _g, _C, _c,                           # Not for export
+
+
+# Provide a PEP 3115 compliant mechanism for class creation
+def new_class(name, bases=(), kwds=None, exec_body=None):
+    """Create a class object dynamically using the appropriate metaclass."""
+    meta, ns, kwds = prepare_class(name, bases, kwds)
+    if exec_body is not None:
+        exec_body(ns)
+    return meta(name, bases, ns, **kwds)
+
+def prepare_class(name, bases=(), kwds=None):
+    """Call the __prepare__ method of the appropriate metaclass.
+
+    Returns (metaclass, namespace, kwds) as a 3-tuple
+
+    *metaclass* is the appropriate metaclass
+    *namespace* is the prepared class namespace
+    *kwds* is an updated copy of the passed in kwds argument with any
+    'metaclass' entry removed. If no kwds argument is passed in, this will
+    be an empty dict.
+    """
+    if kwds is None:
+        kwds = {}
+    else:
+        kwds = dict(kwds) # Don't alter the provided mapping
+    if 'metaclass' in kwds:
+        meta = kwds.pop('metaclass')
+    else:
+        if bases:
+            meta = type(bases[0])
+        else:
+            meta = type
+    if isinstance(meta, type):
+        # when meta is a type, we first determine the most-derived metaclass
+        # instead of invoking the initial candidate directly
+        meta = _calculate_meta(meta, bases)
+    if hasattr(meta, '__prepare__'):
+        ns = meta.__prepare__(name, bases, **kwds)
+    else:
+        ns = {}
+    return meta, ns, kwds
+
+def _calculate_meta(meta, bases):
+    """Calculate the most derived metaclass."""
+    winner = meta
+    for base in bases:
+        base_meta = type(base)
+        if issubclass(winner, base_meta):
+            continue
+        if issubclass(base_meta, winner):
+            winner = base_meta
+            continue
+        # else:
+        raise TypeError("metaclass conflict: "
+                        "the metaclass of a derived class "
+                        "must be a (non-strict) subclass "
+                        "of the metaclasses of all its bases")
+    return winner
+
+class DynamicClassAttribute:
+    """Route attribute access on a class to __getattr__.
+
+    This is a descriptor, used to define attributes that act differently when
+    accessed through an instance and through a class.  Instance access remains
+    normal, but access to an attribute through a class will be routed to the
+    class's __getattr__ method; this is done by raising AttributeError.
+
+    This allows one to have properties active on an instance, and have virtual
+    attributes on the class with the same name (see Enum for an example).
+
+    """
+    def __init__(self, fget=None, fset=None, fdel=None, doc=None):
+        self.fget = fget
+        self.fset = fset
+        self.fdel = fdel
+        # next two lines make DynamicClassAttribute act the same as property
+        self.__doc__ = doc or fget.__doc__
+        self.overwrite_doc = doc is None
+        # support for abstract methods
+        self.__isabstractmethod__ = bool(getattr(fget, '__isabstractmethod__', False))
+
+    def __get__(self, instance, ownerclass=None):
+        if instance is None:
+            if self.__isabstractmethod__:
+                return self
+            raise AttributeError()
+        elif self.fget is None:
+            raise AttributeError("unreadable attribute")
+        return self.fget(instance)
+
+    def __set__(self, instance, value):
+        if self.fset is None:
+            raise AttributeError("can't set attribute")
+        self.fset(instance, value)
+
+    def __delete__(self, instance):
+        if self.fdel is None:
+            raise AttributeError("can't delete attribute")
+        self.fdel(instance)
+
+    def getter(self, fget):
+        fdoc = fget.__doc__ if self.overwrite_doc else None
+        result = type(self)(fget, self.fset, self.fdel, fdoc or self.__doc__)
+        result.overwrite_doc = self.overwrite_doc
+        return result
+
+    def setter(self, fset):
+        result = type(self)(self.fget, fset, self.fdel, self.__doc__)
+        result.overwrite_doc = self.overwrite_doc
+        return result
+
+    def deleter(self, fdel):
+        result = type(self)(self.fget, self.fset, fdel, self.__doc__)
+        result.overwrite_doc = self.overwrite_doc
+        return result
+
+
+import functools as _functools
+import collections.abc as _collections_abc
+
+class _GeneratorWrapper:
+    # TODO: Implement this in C.
+    def __init__(self, gen):
+        self.__wrapped = gen
+        self.__isgen = gen.__class__ is GeneratorType
+        self.__name__ = getattr(gen, '__name__', None)
+        self.__qualname__ = getattr(gen, '__qualname__', None)
+    def send(self, val):
+        return self.__wrapped.send(val)
+    def throw(self, tp, *rest):
+        return self.__wrapped.throw(tp, *rest)
+    def close(self):
+        return self.__wrapped.close()
+    @property
+    def gi_code(self):
+        return self.__wrapped.gi_code
+    @property
+    def gi_frame(self):
+        return self.__wrapped.gi_frame
+    @property
+    def gi_running(self):
+        return self.__wrapped.gi_running
+    @property
+    def gi_yieldfrom(self):
+        return self.__wrapped.gi_yieldfrom
+    cr_code = gi_code
+    cr_frame = gi_frame
+    cr_running = gi_running
+    cr_await = gi_yieldfrom
+    def __next__(self):
+        return next(self.__wrapped)
+    def __iter__(self):
+        if self.__isgen:
+            return self.__wrapped
+        return self
+    __await__ = __iter__
+
+def coroutine(func):
+    """Convert regular generator function to a coroutine."""
+
+    if not callable(func):
+        raise TypeError('types.coroutine() expects a callable')
+
+    if (func.__class__ is FunctionType and
+        getattr(func, '__code__', None).__class__ is CodeType):
+
+        co_flags = func.__code__.co_flags
+
+        # Check if 'func' is a coroutine function.
+        # (0x180 == CO_COROUTINE | CO_ITERABLE_COROUTINE)
+        if co_flags & 0x180:
+            return func
+
+        # Check if 'func' is a generator function.
+        # (0x20 == CO_GENERATOR)
+        if co_flags & 0x20:
+            # TODO: Implement this in C.
+            co = func.__code__
+            func.__code__ = CodeType(
+                co.co_argcount, co.co_kwonlyargcount, co.co_nlocals,
+                co.co_stacksize,
+                co.co_flags | 0x100,  # 0x100 == CO_ITERABLE_COROUTINE
+                co.co_code,
+                co.co_consts, co.co_names, co.co_varnames, co.co_filename,
+                co.co_name, co.co_firstlineno, co.co_lnotab, co.co_freevars,
+                co.co_cellvars)
+            return func
+
+    # The following code is primarily to support functions that
+    # return generator-like objects (for instance generators
+    # compiled with Cython).
+
+    @_functools.wraps(func)
+    def wrapped(*args, **kwargs):
+        coro = func(*args, **kwargs)
+        if (coro.__class__ is CoroutineType or
+            coro.__class__ is GeneratorType and coro.gi_code.co_flags & 0x100):
+            # 'coro' is a native coroutine object or an iterable coroutine
+            return coro
+        if (isinstance(coro, _collections_abc.Generator) and
+            not isinstance(coro, _collections_abc.Coroutine)):
+            # 'coro' is either a pure Python generator iterator, or it
+            # implements collections.abc.Generator (and does not implement
+            # collections.abc.Coroutine).
+            return _GeneratorWrapper(coro)
+        # 'coro' is either an instance of collections.abc.Coroutine or
+        # some other object -- pass it through.
+        return coro
+
+    return wrapped
+
+
+__all__ = [n for n in globals() if n[:1] != '_']
+|#