Merge pull request #761 from larme/fix-replace-hyobject

Add 'replace_hy_obj' to safely replace Hy objects

hy/importer.py

@@ -20,7 +20,7 @@
 # DEALINGS IN THE SOFTWARE.
 
 from hy.compiler import hy_compile, HyTypeError
-from hy.models import HyObject
+from hy.models import HyObject, replace_hy_obj
 from hy.lex import tokenize, LexException
 from hy.errors import HyIOError
 
@@ -107,7 +107,7 @@ def hy_eval(hytree, namespace, module_name):
     foo.end_line = 0
     foo.start_column = 0
     foo.end_column = 0
-    hytree.replace(foo)
+    replace_hy_obj(hytree, foo)
     _ast, expr = hy_compile(hytree, module_name, get_expr=True)
 
     # Spoof the positions in the generated ast...

hy/macros.py

@@ -18,20 +18,13 @@
 # FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
 # DEALINGS IN THE SOFTWARE.
 
+from hy.models import replace_hy_obj, wrap_value
 from hy.models.expression import HyExpression
 from hy.models.string import HyString
-from hy.models.symbol import HySymbol
-from hy.models.list import HyList
-from hy.models.integer import HyInteger
-from hy.models.float import HyFloat
-from hy.models.complex import HyComplex
-from hy.models.dict import HyDict
-from hy._compat import str_type, long_type
 
 from hy.errors import HyTypeError, HyMacroExpansionError
 
 from collections import defaultdict
-import sys
 
 CORE_MACROS = [
     "hy.core.bootstrap",
@@ -106,37 +99,6 @@ def require(source_module, target_module):
         reader_refs[name] = reader
 
 
-# type -> wrapping function mapping for _wrap_value
-_wrappers = {
-    int: HyInteger,
-    bool: lambda x: HySymbol("True") if x else HySymbol("False"),
-    float: HyFloat,
-    complex: HyComplex,
-    str_type: HyString,
-    dict: lambda d: HyDict(_wrap_value(x) for x in sum(d.items(), ())),
-    list: lambda l: HyList(_wrap_value(x) for x in l),
-    tuple: lambda t: HyList(_wrap_value(x) for x in t),
-    type(None): lambda foo: HySymbol("None"),
-    HyExpression: lambda e: HyExpression(_wrap_value(x) for x in e),
-}
-
-if sys.version_info[0] < 3:  # do not add long on python3
-    _wrappers[long_type] = HyInteger
-
-
-def _wrap_value(x):
-    """Wrap `x` into the corresponding Hy type.
-
-    This allows a macro to return an unquoted expression transparently.
-
-    """
-    wrapper = _wrappers.get(type(x))
-    if wrapper is None:
-        return x
-    else:
-        return wrapper(x)
-
-
 def load_macros(module_name):
     """Load the hy builtin macros for module `module_name`.
 
@@ -194,7 +156,8 @@ def macroexpand_1(tree, module_name):
                 m = _hy_macros[None].get(fn)
             if m is not None:
                 try:
-                    obj = _wrap_value(m(*ntree[1:]))
+                    obj = wrap_value(m(*ntree[1:]))
+
                 except HyTypeError as e:
                     if e.expression is None:
                         e.expression = tree
@@ -202,7 +165,7 @@ def macroexpand_1(tree, module_name):
                 except Exception as e:
                     msg = "expanding `" + str(tree[0]) + "': " + repr(e)
                     raise HyMacroExpansionError(tree, msg)
-                obj.replace(tree)
+                replace_hy_obj(obj, tree)
                 return obj
 
         return ntree
@@ -223,4 +186,4 @@ def reader_macroexpand(char, tree, module_name):
         )
 
     expr = _hy_reader[module_name][char](tree)
-    return _wrap_value(expr).replace(tree)
+    return replace_hy_obj(wrap_value(expr), tree)

hy/models/__init__.py

@@ -35,3 +35,35 @@ class HyObject(object):
             raise TypeError("Can't replace a non Hy object with a Hy object")
 
         return self
+
+_wrappers = {}
+
+
+def wrap_value(x):
+    """Wrap `x` into the corresponding Hy type.
+
+    This allows replace_hy_obj to convert a non Hy object to a Hy object.
+
+    This also allows a macro to return an unquoted expression transparently.
+
+    """
+
+    wrapper = _wrappers.get(type(x))
+    if wrapper is None:
+        return x
+    else:
+        return wrapper(x)
+
+
+def replace_hy_obj(obj, other):
+
+    if isinstance(obj, HyObject):
+        return obj.replace(other)
+
+    wrapped_obj = wrap_value(obj)
+
+    if isinstance(wrapped_obj, HyObject):
+        return wrapped_obj.replace(other)
+    else:
+        raise TypeError("Don't know how to wrap a %s object to a HyObject"
+                        % type(obj))

hy/models/complex.py

@@ -18,7 +18,7 @@
 # FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
 # DEALINGS IN THE SOFTWARE.
 
-from hy.models import HyObject
+from hy.models import HyObject, _wrappers
 
 
 class HyComplex(HyObject, complex):
@@ -30,3 +30,5 @@ class HyComplex(HyObject, complex):
     def __new__(cls, number, *args, **kwargs):
         number = complex(number)
         return super(HyComplex, cls).__new__(cls, number)
+
+_wrappers[complex] = HyComplex

hy/models/cons.py

@@ -18,8 +18,7 @@
 # FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
 # DEALINGS IN THE SOFTWARE.
 
-from hy.macros import _wrap_value
+from hy.models import HyObject, replace_hy_obj, wrap_value
-from hy.models import HyObject
 from hy.models.expression import HyExpression
 from hy.models.symbol import HySymbol
 
@@ -42,17 +41,17 @@ class HyCons(HyObject):
                     if cdr[0] in ("unquote", "unquote_splice"):
                         return super(HyCons, cls).__new__(cls)
 
-            return cdr.__class__([_wrap_value(car)] + cdr)
+            return cdr.__class__([wrap_value(car)] + cdr)
 
         elif cdr is None:
-            return HyExpression([_wrap_value(car)])
+            return HyExpression([wrap_value(car)])
 
         else:
             return super(HyCons, cls).__new__(cls)
 
     def __init__(self, car, cdr):
-        self.car = _wrap_value(car)
+        self.car = wrap_value(car)
-        self.cdr = _wrap_value(cdr)
+        self.cdr = wrap_value(cdr)
 
     def __getitem__(self, n):
         if n == 0:
@@ -88,9 +87,9 @@ class HyCons(HyObject):
 
     def replace(self, other):
         if self.car is not None:
-            self.car.replace(other)
+            replace_hy_obj(self.car, other)
         if self.cdr is not None:
-            self.cdr.replace(other)
+            replace_hy_obj(self.cdr, other)
 
         HyObject.replace(self, other)
 

hy/models/dict.py

@@ -18,6 +18,7 @@
 # FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
 # DEALINGS IN THE SOFTWARE.
 
+from hy.models import _wrappers, wrap_value
 from hy.models.list import HyList
 
 
@@ -37,3 +38,5 @@ class HyDict(HyList):
 
     def items(self):
         return list(zip(self.keys(), self.values()))
+
+_wrappers[dict] = lambda d: HyDict(wrap_value(x) for x in sum(d.items(), ()))

hy/models/expression.py

@@ -18,6 +18,7 @@
 # FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
 # DEALINGS IN THE SOFTWARE.
 
+from hy.models import _wrappers, wrap_value
 from hy.models.list import HyList
 
 
@@ -28,3 +29,5 @@ class HyExpression(HyList):
 
     def __repr__(self):
         return "(%s)" % (" ".join([repr(x) for x in self]))
+
+_wrappers[HyExpression] = lambda e: HyExpression(wrap_value(x) for x in e)

hy/models/float.py

@@ -18,7 +18,7 @@
 # FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
 # DEALINGS IN THE SOFTWARE.
 
-from hy.models import HyObject
+from hy.models import HyObject, _wrappers
 
 
 class HyFloat(HyObject, float):
@@ -30,3 +30,5 @@ class HyFloat(HyObject, float):
     def __new__(cls, number, *args, **kwargs):
         number = float(number)
         return super(HyFloat, cls).__new__(cls, number)
+
+_wrappers[float] = HyFloat

hy/models/integer.py

@@ -18,9 +18,11 @@
 # FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
 # DEALINGS IN THE SOFTWARE.
 
-from hy.models import HyObject
+from hy.models import HyObject, _wrappers
 from hy._compat import long_type
 
+import sys
+
 
 class HyInteger(HyObject, long_type):
     """
@@ -32,3 +34,9 @@ class HyInteger(HyObject, long_type):
     def __new__(cls, number, *args, **kwargs):
         number = long_type(number)
         return super(HyInteger, cls).__new__(cls, number)
+
+
+_wrappers[int] = HyInteger
+
+if sys.version_info[0] < 3:  # do not add long on python3
+    _wrappers[long_type] = HyInteger

hy/models/list.py

@@ -18,7 +18,7 @@
 # FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
 # DEALINGS IN THE SOFTWARE.
 
-from hy.models import HyObject
+from hy.models import HyObject, replace_hy_obj, _wrappers, wrap_value
 
 
 class HyList(HyObject, list):
@@ -28,7 +28,7 @@ class HyList(HyObject, list):
 
     def replace(self, other):
         for x in self:
-            x.replace(other)
+            replace_hy_obj(x, other)
 
         HyObject.replace(self, other)
         return self
@@ -49,3 +49,6 @@ class HyList(HyObject, list):
 
     def __repr__(self):
         return "[%s]" % (" ".join([repr(x) for x in self]))
+
+_wrappers[list] = lambda l: HyList(wrap_value(x) for x in l)
+_wrappers[tuple] = lambda t: HyList(wrap_value(x) for x in t)

hy/models/string.py

@@ -18,7 +18,7 @@
 # FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
 # DEALINGS IN THE SOFTWARE.
 
-from hy.models import HyObject
+from hy.models import HyObject, _wrappers
 from hy._compat import str_type
 
 
@@ -29,3 +29,5 @@ class HyString(HyObject, str_type):
     Python version.
     """
     pass
+
+_wrappers[str_type] = HyString

hy/models/symbol.py

@@ -18,6 +18,7 @@
 # FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
 # DEALINGS IN THE SOFTWARE.
 
+from hy.models import _wrappers
 from hy.models.string import HyString
 
 
@@ -28,3 +29,6 @@ class HySymbol(HyString):
 
     def __init__(self, string):
         self += string
+
+_wrappers[bool] = lambda x: HySymbol("True") if x else HySymbol("False")
+_wrappers[type(None)] = lambda foo: HySymbol("None")

tests/models/test_replace_hy_obj.py

@@ -0,0 +1,26 @@
+from hy._compat import long_type, str_type
+from hy.models.string import HyString
+from hy.models.integer import HyInteger
+from hy.models.list import HyList
+
+from hy.models import replace_hy_obj
+
+
+def test_replace_long_type():
+    """ Test replacing integers."""
+    replaced = replace_hy_obj(long_type(0), HyInteger(13))
+    assert replaced == HyInteger(0)
+
+
+def test_replace_string_type():
+    """Test replacing python string"""
+    replaced = replace_hy_obj(str_type("foo"), HyString("bar"))
+    assert replaced == HyString("foo")
+
+
+def test_replace_tuple():
+    """ Test replacing tuples."""
+    replaced = replace_hy_obj((long_type(0), ), HyInteger(13))
+    assert type(replaced) == HyList
+    assert type(replaced[0]) == HyInteger
+    assert replaced == HyList([HyInteger(0)])

tests/models/test_wrap_value.py

@@ -3,18 +3,18 @@ from hy.models.integer import HyInteger
 from hy.models.list import HyList
 from hy.models.expression import HyExpression
 
-from hy.macros import _wrap_value
+from hy.models import wrap_value
 
 
 def test_wrap_long_type():
     """ Test conversion of integers."""
-    wrapped = _wrap_value(long_type(0))
+    wrapped = wrap_value(long_type(0))
     assert type(wrapped) == HyInteger
 
 
 def test_wrap_tuple():
     """ Test conversion of tuples."""
-    wrapped = _wrap_value((HyInteger(0),))
+    wrapped = wrap_value((HyInteger(0),))
     assert type(wrapped) == HyList
     assert type(wrapped[0]) == HyInteger
     assert wrapped == HyList([HyInteger(0)])
@@ -22,7 +22,7 @@ def test_wrap_tuple():
 
 def test_wrap_nested_expr():
     """ Test conversion of HyExpressions with embedded non-HyObjects."""
-    wrapped = _wrap_value(HyExpression([long_type(0)]))
+    wrapped = wrap_value(HyExpression([long_type(0)]))
     assert type(wrapped) == HyExpression
     assert type(wrapped[0]) == HyInteger
     assert wrapped == HyExpression([HyInteger(0)])