Bye-bye python_form parameter. (#554)

* removing python_form parameter from to_python

Author: mmatera

mathics/builtin/inout.py

@@ -439,9 +439,14 @@ class PythonForm(Builtin):
     def apply_python(self, expr, evaluation) -> Expression:
         "MakeBoxes[expr_, PythonForm]"
 
+        def build_python_form(expr):
+            if isinstance(expr, Symbol):
+                return expr.to_sympy()
+            return expr.to_python()
+
         try:
             # from trepan.api import debug; debug()
-            python_equivalent = expr.to_python(python_form=True)
+            python_equivalent = build_python_form(expr)
         except Exception:
             return
         return StringFromPython(python_equivalent)

mathics/core/element.py

@@ -422,20 +422,14 @@ def user_hash(self, update) -> None:
         # __hash__ might only hash a sample of the data available.
         raise NotImplementedError
 
-    def to_python(self, *args, python_form: bool = False, **kwargs):
+    def to_python(self, *args, **kwargs):
         # Returns a native builtin Python object
         # something in (int, float, complex, str, tuple, list or dict.).
         # (See discussions in
         #  https://github.com/Mathics3/mathics-core/discussions/550
         # and
         # https://github.com/Mathics3/mathics-core/pull/551
         #
-        #
-        # if n_evaluation is an Evaluation object, then the expression
-        # is passed by an eval_N().
-        # If python_form is True, the standard behaviour is changed,
-        # and it seems to behave like to_sympy....
-
         raise NotImplementedError
 
     def to_mpmath(self):

mathics/core/expression.py

@@ -1382,7 +1382,9 @@ def to_python(self, *args, **kwargs):
         """
         from mathics.builtin.base import mathics_to_python
 
-        n_evaluation = kwargs.get("n_evaluation")
+        n_evaluation = kwargs.get("n_evaluation", None)
+        assert n_evaluation is None
+
         head = self._head
         if head is SymbolFunction:
 
@@ -1416,6 +1418,9 @@ def to_python(self, *args, **kwargs):
             #         keywords=[],
             #         )
             return py_obj
+
+        # Notice that in this case, `to_python` returns a Mathics Expression object,
+        # instead of a builtin native object.
         return self
 
     def to_sympy(self, **kwargs):

mathics/core/symbols.py

@@ -596,22 +596,12 @@ def to_python(self, *args, python_form: bool = False, **kwargs):
             if value is not self:
                 return value.to_python()
 
-        if python_form:
-            # TODO: consider to return self.value if available.
-            # For general symbols, one possibility would be to
-            # return a sympy symbol, also stored in value.
-
-            # Also, why we need this parameter? If the idea is
-            # that to_python returns native (builtin) Python types,
-            # then to get a sympy object, we should use to_sympy.
-            return self.to_sympy(**kwargs)
-        else:
-            # For general symbols, the default behaviour is
-            # to return a 'str'. The reason seems to be
-            # that native (builtin) Python types
-            # are better for being used as keys in
-            # dictionaries.
-            return self.name
+        # For general symbols, the default behaviour is
+        # to return a 'str'. The reason seems to be
+        # that native (builtin) Python types
+        # are better for being used as keys in
+        # dictionaries.
+        return self.name
 
     def to_sympy(self, **kwargs):
         from mathics.builtin import mathics_to_sympy