Replaced deprecated setup.py with setup.cfg

Also bumped version to 0.7.5, with packaging being the
only change.

The old setup.py method is deprecated and will be removed
in future python3 versions. The rationale behind this is
that the setup.py script runs arbitrary code at install time.

Our setup.py file used to dynamically determine the current
version at install time by querying git. While this makes
it more forgiving as a developer (setting a new tag is enough,
no version update in any file is necessary) it's generally bad
practice.

I suggest setting a github action that fills this role, if
possible. Otherwise we must remember to manually update the
"version" attribute in the setup.cfg file when releasing a
new version.

nml/expression/__init__.py

@@ -38,7 +38,6 @@
 
 is_valid_id = re.compile("[a-zA-Z_][a-zA-Z0-9_]{3}$")
 
-
 def identifier_to_print(name):
     """
     Check whether the given name is a valid 4 letter identifier to print
@@ -50,3 +49,4 @@ def identifier_to_print(name):
     if is_valid_id.match(name):
         return name
     return '"{}"'.format(name)
+

setup.cfg

@@ -0,0 +1,30 @@
+[metadata]
+name = nml
+version = 0.7.5
+description = An OpenTTD NewGRF compiler for the nml language
+long_description = file: README.md
+long_description_content_type = text/markdown
+home_page = https://github.com/OpenTTD/nml
+author = NML Development Team
+author_email = [email protected]
+license = GPL-2.0+
+classifiers =
+  Development Status :: 2 - Pre-Alpha
+  Intended Audience :: Developers
+  License :: OSI Approved :: GNU General Public License (GPL)
+  Operating System :: OS Independent
+  Programming Language :: Python :: 3
+  Topic :: Software Development :: Compilers
+
+[options]
+packages = nml,nml.actions,nml.ast,nml.editors,nml.expression,nml.generated
+python_requires = >= 3.5
+setup_requires =
+  setuptools >= 38.3.0
+install_requires =
+  Pillow>=3.4
+  ply
+
+[options.entry_points]
+console_scripts =
+  nmlc = nml.main:run

setup.py

@@ -1,64 +1,2 @@
-#!/usr/bin/env python3
-
-from setuptools import Extension, find_packages, setup
-from setuptools.command.build_py import build_py
-
-try:
-    # Update the version by querying git if possible.
-    from nml import version_update
-
-    NML_VERSION = version_update.get_and_write_version()
-except ImportError:
-    # version_update is excluded from released tarballs, so that
-    #  only the predetermined version is used when building from one.
-    from nml import version_info
-
-    NML_VERSION = version_info.get_nml_version()
-
-
-class NMLBuildPy(build_py):
-    def run(self):
-        # Create a parser so that nml/generated/{parse,lex}tab.py are generated.
-        from nml import parser
-
-        parser.NMLParser(rebuild=True)
-        # Then continue with the normal setuptools build.
-        super().run()
-
-
-setup(
-    name="nml",
-    version=NML_VERSION,
-    packages=find_packages(),
-    description="An OpenTTD NewGRF compiler for the nml language",
-    long_description=(
-        "A tool to compile NewGRFs for OpenTTD from nml files"
-        "NML is a meta-language that aims to be a lot simpler to"
-        " learn and use than nfo used traditionally to write NewGRFs."
-    ),
-    license="GPL-2.0+",
-    classifiers=[
-        "Development Status :: 2 - Pre-Alpha",
-        "Environment :: Console",
-        "Intended Audience :: Developers",
-        "License :: OSI Approved :: GNU General Public License (GPL)",
-        "Operating System :: OS Independent",
-        "Programming Language :: Python :: 3",
-        "Programming Language :: Python :: 3.5",
-        "Programming Language :: Python :: 3.6",
-        "Programming Language :: Python :: 3.7",
-        "Programming Language :: Python :: 3.8",
-        "Topic :: Software Development :: Compilers",
-    ],
-    url="https://github.com/OpenTTD/nml",
-    author="NML Development Team",
-    author_email="[email protected]",
-    entry_points={"console_scripts": ["nmlc = nml.main:run"]},
-    ext_modules=[Extension("nml_lz77", ["nml/_lz77.c"], optional=True)],
-    python_requires=">=3.5",
-    install_requires=[
-        "Pillow>=3.4",
-        "ply",
-    ],
-    cmdclass={"build_py": NMLBuildPy},
-)
+from setuptools import setup
+setup()