Add Python 3.7 compatibility

scico/__init__.py

@@ -12,6 +12,8 @@
 
 import sys
 
+from . import _python37  # python 3.7 compatibility
+
 # isort: off
 from ._autograd import grad, jacrev, linear_adjoint, value_and_grad
 

scico/_python37.py

@@ -0,0 +1,24 @@
+# Copyright (C) 2021-2022 by SCICO Developers
+# All rights reserved. BSD 3-clause License.
+# This file is part of the SCICO package. Details of the copyright and
+# user license can be found in the 'LICENSE' file distributed with the
+# package.
+
+""" Alter the behavior of (monkey patch) several modules so that SCICO
+is compatible with Python 3.7, allowing it to run on Google Colab.
+This file should be removed when/if Colab upgrades to Python 3.8.
+"""
+
+import sys
+
+if sys.version_info.major == 3 and sys.version_info.minor == 7:
+    import typing
+
+    typing.Literal = typing.Any  # type: ignore
+
+    import math
+    from functools import reduce
+    from operator import mul
+
+    # math.prod = (lambda fun, op: lambda iterable: fun(op, iterable, 1))(reduce, mul)  # type: ignore
+    math.prod = lambda iterable: reduce(mul, iterable, 1)  # type: ignore

scico/_version.py

@@ -7,9 +7,9 @@
 
 """Support functions for determining the package version."""
 
-
 import os
 import re
+import sys
 from ast import parse
 from subprocess import PIPE, Popen
 from typing import Any, Optional, Tuple, Union
@@ -41,7 +41,12 @@ def variable_assign_value(path: str, var: str) -> Any:
     with open(path) as f:
         try:
             # See http://stackoverflow.com/questions/2058802
-            value = parse(next(filter(lambda line: line.startswith(var), f))).body[0].value.s  # type: ignore
+            value_obj = parse(next(filter(lambda line: line.startswith(var), f))).body[0].value  # type: ignore
+            if sys.version_info.major == 3 and sys.version_info.minor == 7:
+                value = value_obj.n  # type: ignore
+            else:
+                value = value_obj.s  # type: ignore
+
         except StopIteration:
             raise RuntimeError(f"Could not find initialization of variable {var}")
     return value

setup.py

@@ -60,7 +60,7 @@
         f"requirements.txt ({req_jax_ver}) do not match"
     )
 
-python_requires = ">=3.8"
+python_requires = ">=3.7"
 tests_require = ["pytest", "pytest-runner"]
 
 extra_require_files = [