Python-ify lab4/assembler.

Practicing using Python best practices. Changes made:

* Update assembler's .gitignore to latest GitHub version.
* Add docstrings to all functions.
* Rewrite the main assembler.py file to use a main() function.
* Add type annotations to have the script pass mypy.
* Modify MachineCode class member names to properly reflect none of the members are public.
* Make linter modifications to have the script pass flake8.

Author: jlperona

lab4/assembler/.gitignore

@@ -20,6 +20,7 @@ parts/
 sdist/
 var/
 wheels/
+share/python-wheels/
 *.egg-info/
 .installed.cfg
 *.egg
@@ -38,14 +39,17 @@ pip-delete-this-directory.txt
 # Unit test / coverage reports
 htmlcov/
 .tox/
+.nox/
 .coverage
 .coverage.*
 .cache
 nosetests.xml
 coverage.xml
 *.cover
+*.py,cover
 .hypothesis/
 .pytest_cache/
+cover/
 
 # Translations
 *.mo
@@ -55,6 +59,7 @@ coverage.xml
 *.log
 local_settings.py
 db.sqlite3
+db.sqlite3-journal
 
 # Flask stuff:
 instance/
@@ -67,16 +72,34 @@ instance/
 docs/_build/
 
 # PyBuilder
+.pybuilder/
 target/
 
 # Jupyter Notebook
 .ipynb_checkpoints
 
+# IPython
+profile_default/
+ipython_config.py
+
 # pyenv
-.python-version
+#   For a library or package, you might want to ignore these files since the code is
+#   intended to run in multiple environments; otherwise, check them in:
+# .python-version
+
+# pipenv
+#   According to pypa/pipenv#598, it is recommended to include Pipfile.lock in version control.
+#   However, in case of collaboration, if having platform-specific dependencies or dependencies
+#   having no cross-platform support, pipenv may install dependencies that don't work, or not
+#   install all needed dependencies.
+#Pipfile.lock
+
+# PEP 582; used by e.g. github.com/David-OConnor/pyflow
+__pypackages__/
 
-# celery beat schedule file
+# Celery stuff
 celerybeat-schedule
+celerybeat.pid
 
 # SageMath parsed files
 *.sage.py
@@ -102,3 +125,14 @@ venv.bak/
 
 # mypy
 .mypy_cache/
+.dmypy.json
+dmypy.json
+
+# Pyre type checker
+.pyre/
+
+# pytype static type analyzer
+.pytype/
+
+# Cython debug symbols
+cython_debug/

lab4/assembler/assembler.py

@@ -3,18 +3,28 @@
 import utils.output
 
 from utils.machinecode import MachineCode
+from typing import List
 
-# command line argument processing
-args = utils.commandline.argument_parsing()
 
-# input file processing
-all_machine_code = []
-utils.input.parse_input(args, all_machine_code)
+def main() -> None:
+    """Take in input CSV with assembler instructions.
+    Write assembly hex to stdout or output file.
+    """
+    # command line argument processing
+    args = utils.commandline.argument_parsing()
 
-# data processing
-for current_machine_code in all_machine_code:
-    current_machine_code.convert_to_bin()
-    current_machine_code.convert_to_hex()
+    # input file processing
+    all_machine_code: List['MachineCode'] = []
+    utils.input.parse_input(args, all_machine_code)
 
-# output file processing
-utils.output.write_output(args, all_machine_code)
+    # data processing
+    for current_machine_code in all_machine_code:
+        current_machine_code.convert_to_bin()
+        current_machine_code.convert_to_hex()
+
+    # output file processing
+    utils.output.write_output(args, all_machine_code)
+
+
+if __name__ == "__main__":
+    main()

lab4/assembler/utils/commandline.py

@@ -1,40 +1,45 @@
 import argparse
 
-# command line argument parsing
-def argument_parsing():
+
+def argument_parsing() -> argparse.Namespace:
+    """Parse command line arguments with argparse."""
     parser = argparse.ArgumentParser(
-        description = 'Take in a CSV file with Lab 4 assembly code. '
-            'Output a text file to load into a RAM in Logisim Evolution. '
-            'All values, including immediate values, must be in decimal. '
-            'Immediate values can be negative.'
+        description='Take in a CSV file with Lab 4 assembly code. Output '
+                    'a text file to load into a RAM in Logisim Evolution. All '
+                    'values, including immediate values, must be in decimal. '
+                    'Immediate values can be negative.'
     )
 
     # mandatory input file
-    parser.add_argument('infile',
-        metavar = 'input.csv',
-        help = 'Input CSV file with valid assembly code.'
+    parser.add_argument(
+        'infile',
+        metavar='input.csv',
+        help='Input CSV file with valid assembly code.'
     )
 
     # optional output file
-    parser.add_argument('outfile',
-        nargs = '?',
-        help = 'If specified, write to an output file instead of the console. '
-            'Output file will be overwritten.'
+    parser.add_argument(
+        'outfile',
+        nargs='?',
+        help='If specified, write to an output file instead of the console. '
+             'Output file will be overwritten.'
     )
 
     # no header flag
-    parser.add_argument('-n',
+    parser.add_argument(
+        '-n',
         '--noheader',
-        action = 'store_true',
-        help = 'Treat the first row of the file as a line of code. '
-            'Normal behavior treats the first line as a header and skips it.'
+        action='store_true',
+        help='Treat the first row of the file as a line of code. '
+             'Normal behavior treats the first line as a header and skips it.'
     )
 
     # binary flag
-    parser.add_argument('-b',
+    parser.add_argument(
+        '-b',
         '--binary',
-        action = 'store_true',
-        help = 'Export binary instead of hexadecimal.'
+        action='store_true',
+        help='Export binary instead of hexadecimal.'
     )
 
     return parser.parse_args()

lab4/assembler/utils/input.py

@@ -1,16 +1,16 @@
 import csv
-import sys
 
 from utils.machinecode import MachineCode
 
-# input file parsing
-def parse_input(args, all_machine_code):
+
+def parse_input(args, all_machine_code) -> None:
+    """Parse input CSV into a list of MachineCode objects."""
     # open file and begin reading data
     with open(args.infile) as infile:
         csvreader = csv.reader(infile)
 
         # skip header line depending on command line arguments
-        if args.noheader == False:
+        if args.noheader is False:
             next(csvreader)
 
         # for every line in the csv file
@@ -43,5 +43,6 @@ def parse_input(args, all_machine_code):
                 raise Exception(invalid_assembly_exception) from None
 
             # create new machine code
-            current_machine_code = MachineCode(op, rd, rs1, rs2, imm, line_number)
+            current_machine_code = MachineCode(op, rd, rs1, rs2,
+                                               imm, line_number)
             all_machine_code.append(current_machine_code)