h2oai · st-pasha · Jan 22, 2019 · Jan 18, 2019 · Jan 22, 2019 · Jan 22, 2019
diff --git a/CHANGELOG.md b/CHANGELOG.md
@@ -173,6 +173,11 @@ and this project adheres to [Semantic Versioning](http://semver.org/).
   deprecated, they will be removed in 0.9.0. Please use `.to_list()`,
   `.to_pandas()` and `.to_numpy()` instead.
 
+- Calling a frame object `DT(rows=i, select=j, groupby=g, join=z, sort=s)` is
+  now deprecated. Use the expression `DT[i, j, by(g), join(z), sort(s)]`
+  instead, where symbols `by()`, `join()` and `sort()` can all be imported
+  from the `datatable` namespace (#1579).
+
 
 ### Removed
 

diff --git a/c/datatablemodule.cc b/c/datatablemodule.cc
@@ -35,7 +35,6 @@ extern void init_jay();
 
 namespace py {
   PyObject* fread_fn = nullptr;
-  PyObject* fallback_makedatatable = nullptr;
 }
 
 
@@ -106,7 +105,6 @@ PyObject* register_function(PyObject*, PyObject *args) {
   else if (n == 6) replace_dtWarning(fnref);
   else if (n == 7) py::Frame_Type = fnref;
   else if (n == 8) py::fread_fn = fnref;
-  else if (n == 9) py::fallback_makedatatable = fnref;
   else {
     throw ValueError() << "Incorrect function index: " << n;
   }
@@ -194,12 +192,6 @@ void DatatableModule::init_methods() {
   add(METHODv(register_function));
   add(METHOD0(get_internal_function_ptrs));
   add(METHOD0(get_integer_sizes));
-  add(METHODv(expr_binaryop));
-  add(METHODv(expr_cast));
-  add(METHODv(expr_column));
-  add(METHODv(expr_reduceop));
-  add(METHODv(expr_count));
-  add(METHODv(expr_unaryop));
   add(METHOD0(is_debug_mode));
   add(METHOD0(has_omp_support));
 

diff --git a/c/expr/base_expr.cc b/c/expr/base_expr.cc
@@ -648,7 +648,7 @@ void py::base_expr::Type::init_methods_and_getsets(
 
 
 bool is_PyBaseExpr(const py::_obj& obj) {
-  static auto BaseExprType = py::oobj::import("datatable.graph", "BaseExpr");
+  static auto BaseExprType = py::oobj::import("datatable.expr", "BaseExpr");
   return PyObject_IsInstance(obj.to_borrowed_ref(),
                              BaseExprType.to_borrowed_ref());
 }
diff --git a/c/expr/by_node.cc b/c/expr/by_node.cc
@@ -19,9 +19,11 @@
 // FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
 // IN THE SOFTWARE.
 //------------------------------------------------------------------------------
+#include "expr/base_expr.h"
 #include "expr/by_node.h"
 #include "expr/collist.h"
 #include "expr/py_expr.h"
+#include "expr/workframe.h"
 #include "python/arg.h"
 #include "python/tuple.h"
 #include "utils/exceptions.h"

diff --git a/c/expr/collist.cc b/c/expr/collist.cc
@@ -19,7 +19,9 @@
 // FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
 // IN THE SOFTWARE.
 //------------------------------------------------------------------------------
+#include "expr/base_expr.h"
 #include "expr/collist.h"
+#include "expr/workframe.h"
 #include "utils/exceptions.h"
 #include "datatable.h"
 
@@ -112,7 +114,7 @@ class collist_maker
           _process_element(elem);
         }
       }
-      else {
+      else if (!src.is_none()) {
         throw TypeError()
           << "Unsupported " << srcname << " of type " << src.typeobj();
       }
@@ -170,6 +172,7 @@ class collist_maker
       else if (elem.is_type())   _process_element_type(elem);
       else if (elem.is_ltype())  _process_element_ltype(elem);
       else if (elem.is_stype())  _process_element_stype(elem);
+      else if (elem.is_none()) return;
       else {
         throw TypeError()
             << "Element " << k << " in " << srcname << " list has type `"

diff --git a/c/expr/collist.h b/c/expr/collist.h
@@ -21,15 +21,17 @@
 //------------------------------------------------------------------------------
 #ifndef dt_EXPR_COLLIST_h
 #define dt_EXPR_COLLIST_h
+#include <memory>
+#include <string>
 #include <vector>
-#include "expr/base_expr.h"
-#include "expr/workframe.h"
 #include "python/obj.h"
 
 namespace dt {
 class collist;
+class base_expr;
+class workframe;
 
-
+using strvec = std::vector<std::string>;
 using exprvec = std::vector<std::unique_ptr<dt::base_expr>>;
 using intvec = std::vector<size_t>;
 using collist_ptr = std::unique_ptr<collist>;

diff --git a/c/expr/py_expr.cc b/c/expr/py_expr.cc
diff --git a/c/expr/py_expr.h b/c/expr/py_expr.h
@@ -12,47 +12,6 @@
 #include "groupby.h"
 
 
-DECLARE_FUNCTION(
-  expr_binaryop,
-  "expr_binaryop(op, lhs, rhs)\n\n"
-  "\n",
-  dt_EXPR_PY_EXPR_CC)
-
-DECLARE_FUNCTION(
-  expr_cast,
-  "expr_cast(col, stype)\n\n"
-  "Convert column into new stype.\n",
-  dt_EXPR_PY_EXPR_CC)
-
-DECLARE_FUNCTION(
-  expr_column,
-  "expr_column(dt, i, rowindex)\n\n"
-  "Retrieve column `i` from the DataTable `dt`, replacing its rowindex with\n"
-  "the provided one and then materializing.\n",
-  dt_EXPR_PY_EXPR_CC)
-
-DECLARE_FUNCTION(
-  expr_reduceop,
-  "expr_reduceop(op, col, groupby)\n\n"
-  "Compute a reduction over the provided column, using the provided Groupby\n"
-  "object.\n",
-  dt_EXPR_PY_EXPR_CC)
-
-DECLARE_FUNCTION(
-  expr_unaryop,
-  "expr_unaryop(op, col)\n\n"
-  "Apply unary operator `op` to the column `col` and return the resulting \n"
-  "column.\n",
-  dt_EXPR_PY_EXPR_CC)
-
-DECLARE_FUNCTION(
-  expr_count,
-  "expr_count(dt, groupby)\n\n"
-  "Compute number of rows in each group if the Groupby object is provided, otherwise simply\n"
-  "return number of rows in dataframe.\n",
-  dt_EXPR_PY_EXPR_CC)
-
-
 namespace expr {
 
 typedef void (*mapperfn)(int64_t row0, int64_t row1, void** params);

diff --git a/c/expr/repl_node.cc b/c/expr/repl_node.cc
@@ -20,8 +20,11 @@
 // IN THE SOFTWARE.
 //------------------------------------------------------------------------------
 #include <unordered_map>
+#include "datatable.h"
+#include "expr/base_expr.h"
 #include "expr/collist.h"
 #include "expr/repl_node.h"
+#include "expr/workframe.h"
 #include "utils/exceptions.h"
 
 namespace dt {

diff --git a/c/expr/workframe.cc b/c/expr/workframe.cc
@@ -19,6 +19,7 @@
 // FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
 // IN THE SOFTWARE.
 //------------------------------------------------------------------------------
+#include "expr/base_expr.h"
 #include "expr/collist.h"
 #include "expr/workframe.h"
 #include "frame/py_frame.h"

diff --git a/c/frame/py_frame.h b/c/frame/py_frame.h
@@ -130,7 +130,6 @@ class Frame : public PyObject {
 
 extern PyObject* Frame_Type;
 extern PyObject* fread_fn;
-extern PyObject* fallback_makedatatable;
 
 }  // namespace py
 

diff --git a/datatable/__init__.py b/datatable/__init__.py
@@ -1,19 +1,34 @@
-#!/usr/bin/env python3
-# © H2O.ai 2018; -*- encoding: utf-8 -*-
-#   This Source Code Form is subject to the terms of the Mozilla Public
-#   License, v. 2.0. If a copy of the MPL was not distributed with this
-#   file, You can obtain one at http://mozilla.org/MPL/2.0/.
+#!/usr/bin/env python
+#-------------------------------------------------------------------------------
+# Copyright 2018 H2O.ai
+#
+# Permission is hereby granted, free of charge, to any person obtaining a
+# copy of this software and associated documentation files (the "Software"),
+# to deal in the Software without restriction, including without limitation
+# the rights to use, copy, modify, merge, publish, distribute, sublicense,
+# and/or sell copies of the Software, and to permit persons to whom the
+# Software is furnished to do so, subject to the following conditions:
+#
+# The above copyright notice and this permission notice shall be included in
+# all copies or substantial portions of the Software.
+#
+# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+# FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
+# IN THE SOFTWARE.
 #-------------------------------------------------------------------------------
 from .__version__ import version as __version__
 from .dt_append import rbind, cbind
 from .frame import Frame
 from .expr import (mean, min, max, sd, isna, sum, count, first, abs, exp,
-                   log, log10)
+                   log, log10, f, g)
 from .fread import fread, GenericReader, FreadWarning
-from .graph import f, g, join, by
 from .lib._datatable import (
     unique, union, intersect, setdiff, symdiff,
-    repeat, sort
+    repeat, by, join, sort
 )
 from .nff import save, open
 from .options import options

diff --git a/datatable/expr/__init__.py b/datatable/expr/__init__.py
@@ -5,12 +5,12 @@
 #   file, You can obtain one at http://mozilla.org/MPL/2.0/.
 #-------------------------------------------------------------------------------
 
-from datatable.graph.dtproxy import f
 from .abs_expr import abs
 from .base_expr import BaseExpr
 from .binary_expr import BinaryOpExpr
 from .cast_expr import CastExpr
 from .column_expr import ColSelectorExpr, NewColumnExpr
+from .dtproxy import f, g
 from .exp_expr import exp, log, log10
 from .isna_expr import isna
 from .literal_expr import LiteralExpr

diff --git a/datatable/expr/abs_expr.py b/datatable/expr/abs_expr.py
@@ -15,8 +15,8 @@
 # limitations under the License.
 #-------------------------------------------------------------------------------
 from .base_expr import BaseExpr
+from .dtproxy import f
 from .unary_expr import UnaryOpExpr
-from datatable.graph.dtproxy import f
 from datatable.lib import core
 
 __all__ = ("abs", )

diff --git a/datatable/graph/dtproxy.py → datatable/expr/dtproxy.py b/datatable/graph/dtproxy.py → datatable/expr/dtproxy.py
@@ -5,7 +5,7 @@
 #   file, You can obtain one at http://mozilla.org/MPL/2.0/.
 #-------------------------------------------------------------------------------
 
-from datatable.expr.column_expr import ColSelectorExpr
+from .column_expr import ColSelectorExpr
 
 __all__ = ("f", "g")