Updates from technical review of chapter 2 and minor updates based on development review of other chapters

Author: davecom

KNN/knn.py

@@ -55,7 +55,7 @@ def classify(self, k: int, data_point: DP) -> str:
         neighbors = self.nearest(k, data_point)
         return Counter(neighbor.kind for neighbor in neighbors).most_common(1)[0][0]
 
-    # Predict a  numeric property of a data point based on the k nearest neighbors
+    # Predict a numeric property of a data point based on the k nearest neighbors
     # Find the average of that property from the neighbors and return it
     def predict(self, k: int, data_point: DP, property_name: str) -> float:
         neighbors = self.nearest(k, data_point)

NESEmulator/ppu.py

@@ -41,7 +41,7 @@ def __init__(self, rom: ROM):
         # PPU Memory
         self.spr = array('B', [0] * SPR_RAM_SIZE)  # sprite ram
         self.nametables = array('B', [0] * NAMETABLE_SIZE)  # nametable ram
-        self.palette = array('B', [0] * PALETTE_SIZE)  # pallete ram
+        self.palette = array('B', [0] * PALETTE_SIZE)  # palette ram
         # Registers
         self.addr = 0  # main PPU address register
         self.addr_write_latch = False

NESEmulator/rom.py

@@ -36,7 +36,7 @@ def __init__(self, filename: str):
                 print("Invalid ROM Header Signature")
             else:
                 print("Valid ROM Header Signature")
-            # Untangle Mapper - one nybble in flags6 and one nybble in flags7
+            # Untangle Mapper - one nibble in flags6 and one nibble in flags7
             self.mapper = (self.header.flags7 & 0xF0) | (
                     (self.header.flags6 & 0xF0) >> 4)
             print(f"Mapper {self.mapper}")

NanoBASIC/errors.py

@@ -0,0 +1,43 @@
+# NanoBASIC/errors.py
+# From Fun Computer Science Projects in Python
+# Copyright 2024 David Kopec
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+# http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+#
+# DESCRIPTION
+# The errors module contains the custom exceptions used in the NanoBASIC
+# interpreter including ParserError and InterpreterError.
+from NanoBASIC.tokenizer import Token
+from NanoBASIC.nodes import Node
+
+
+class NanoBASICError(Exception):
+    def __init__(self, message: str, line_num: int, column: int):
+        super().__init__(message)
+        self.message = message
+        self.line_num = line_num
+        self.column = column
+
+    def __str__(self):
+        return (f"{self.message} Occurred at line {self.line_num} "
+                f"and column {self.column}")
+
+
+class ParserError(NanoBASICError):
+    def __init__(self, message: str, token: Token):
+        super().__init__(message, token.line_num, token.col_start)
+
+
+class InterpreterError(NanoBASICError):
+    def __init__(self, message: str, node: Node):
+        super().__init__(message, node.line_num, node.col_start)

NanoBASIC/interpreter.py

@@ -21,20 +21,11 @@
 # just an array of statement nodes; each node is something of a tree in itself. The interpreter
 # translates the meaning of each statement node into Python code that can be run "live."
 from NanoBASIC.nodes import *
+from NanoBASIC.errors import InterpreterError
 from collections import deque
 
 
 class Interpreter:
-    class InterpreterError(Exception):
-        def __init__(self, message: str, node: Node):
-            self.message = message
-            self.line_num = node.line_num
-            self.column = node.col_start
-
-        def __str__(self):
-            return (f"{self.message} Occurred at line {self.line_num} "
-                    f"and column {self.column}")
-
     def __init__(self, statements: list[Statement]):
         self.statements = statements
         self.variable_table: dict[str, int] = {}
@@ -75,17 +66,17 @@ def interpret(self, statement: Statement):
                 if (line_index := self.find_line_index(go_to_line_id)) is not None:
                     self.statement_index = line_index
                 else:
-                    raise Interpreter.InterpreterError("No GOTO line id.", self.current)
+                    raise InterpreterError("No GOTO line id.", self.current)
             case GoSubStatement(line_expr=line_expr):
                 go_sub_line_id = self.evaluate_numeric(line_expr)
                 if (line_index := self.find_line_index(go_sub_line_id)) is not None:
                     self.subroutine_stack.append(self.statement_index + 1)  # Setup for RETURN
                     self.statement_index = line_index
                 else:
-                    raise Interpreter.InterpreterError("No GOSUB line id.", self.current)
+                    raise InterpreterError("No GOSUB line id.", self.current)
             case ReturnStatement():
                 if not self.subroutine_stack:  # Check if the stack is empty
-                    raise Interpreter.InterpreterError("RETURN without GOSUB.", self.current)
+                    raise InterpreterError("RETURN without GOSUB.", self.current)
                 self.statement_index = self.subroutine_stack.pop()
             case PrintStatement(printables=printables):
                 accumulated_string: str = ""
@@ -104,8 +95,8 @@ def interpret(self, statement: Statement):
                 else:
                     self.statement_index += 1
             case _:
-                raise Interpreter.InterpreterError(f"Unexpected item {self.current} "
-                                                   f"in statement list.", self.current)
+                raise InterpreterError(f"Unexpected item {self.current} "
+                                       f"in statement list.", self.current)
 
     def evaluate_numeric(self, numeric_expression: NumericExpression) -> int:
         match numeric_expression:
@@ -115,14 +106,14 @@ def evaluate_numeric(self, numeric_expression: NumericExpression) -> int:
                 if name in self.variable_table:
                     return self.variable_table[name]
                 else:
-                    raise Interpreter.InterpreterError(f"Var {name} used "
-                                                       f"before initialized.", numeric_expression)
+                    raise InterpreterError(f"Var {name} used "
+                                           f"before initialized.", numeric_expression)
             case UnaryOperation(operator=operator, expr=expr):
                 if operator is TokenType.MINUS:
                     return -self.evaluate_numeric(expr)
                 else:
-                    raise Interpreter.InterpreterError(f"Expected - "
-                                                       f"but got {operator}.", numeric_expression)
+                    raise InterpreterError(f"Expected - "
+                                           f"but got {operator}.", numeric_expression)
             case BinaryOperation(operator=operator, left_expr=left, right_expr=right):
                 if operator is TokenType.PLUS:
                     return self.evaluate_numeric(left) + self.evaluate_numeric(right)
@@ -133,11 +124,11 @@ def evaluate_numeric(self, numeric_expression: NumericExpression) -> int:
                 elif operator is TokenType.DIVIDE:
                     return self.evaluate_numeric(left) // self.evaluate_numeric(right)
                 else:
-                    raise Interpreter.InterpreterError(f"Unexpected binary operator "
-                                                       f"{operator}.", numeric_expression)
+                    raise InterpreterError(f"Unexpected binary operator "
+                                           f"{operator}.", numeric_expression)
             case _:
-                raise Interpreter.InterpreterError("Expected numeric expression.",
-                                                   numeric_expression)
+                raise InterpreterError("Expected numeric expression.",
+                                       numeric_expression)
 
     def evaluate_boolean(self, boolean_expression: BooleanExpression) -> bool:
         left = self.evaluate_numeric(boolean_expression.left_expr)
@@ -156,5 +147,5 @@ def evaluate_boolean(self, boolean_expression: BooleanExpression) -> bool:
             case TokenType.NOT_EQUAL:
                 return left != right
             case _:
-                raise Interpreter.InterpreterError(f"Unexpected boolean operator "
-                                                   f"{boolean_expression.operator}.", boolean_expression)
+                raise InterpreterError(f"Unexpected boolean operator "
+                                       f"{boolean_expression.operator}.", boolean_expression)

NanoBASIC/nodes.py

@@ -47,7 +47,7 @@ class NumericExpression(Node):
     pass
 
 
-# A numeric expression with two operands like +, -, *, and /
+# A numeric expression with two operands like 2 + 2 or 8 / 4
 @dataclass(frozen=True)
 class BinaryOperation(NumericExpression):
     operator: TokenType
@@ -58,7 +58,7 @@ def __repr__(self) -> str:
         return f"{self.left_expr} {self.operator} {self.right_expr}"
 
 
-# A numeric expression with one operand like -
+# A numeric expression with one operand like -4
 @dataclass(frozen=True)
 class UnaryOperation(NumericExpression):
     operator: TokenType

NanoBASIC/parser.py

@@ -29,19 +29,10 @@
 from NanoBASIC.tokenizer import Token
 from typing import cast
 from NanoBASIC.nodes import *
+from NanoBASIC.errors import ParserError
 
 
 class Parser:
-    class ParserError(Exception):
-        def __init__(self, message: str, token: Token):
-            self.message = message
-            self.line_num = token.line_num
-            self.column = token.col_start
-
-        def __str__(self):
-            return (f"{self.message} Occurred at line {self.line_num} "
-                    f"and column {self.column}")
-
     def __init__(self, tokens: list[Token]):
         self.tokens = tokens
         self.token_index: int = 0
@@ -53,8 +44,8 @@ def out_of_tokens(self) -> bool:
     @property
     def current(self) -> Token:
         if self.out_of_tokens:
-            raise (Parser.ParserError(f"No tokens after "
-                                      f"{self.previous.kind}", self.previous))
+            raise (ParserError(f"No tokens after "
+                               f"{self.previous.kind}", self.previous))
         return self.tokens[self.token_index]
 
     @property
@@ -65,8 +56,8 @@ def consume(self, kind: TokenType) -> Token:
         if self.current.kind is kind:
             self.token_index += 1
             return self.previous
-        raise Parser.ParserError(f"Expected {kind} after {self.previous}"
-                                 f"but got {self.current}.", self.current)
+        raise ParserError(f"Expected {kind} after {self.previous}"
+                          f"but got {self.current}.", self.current)
 
     def parse(self) -> list[Statement]:
         statements: list[Statement] = []
@@ -93,8 +84,8 @@ def parse_statement(self, line_id: int) -> Statement:
                 return self.parse_gosub(line_id)
             case TokenType.RETURN_T:
                 return self.parse_return(line_id)
-        raise Parser.ParserError("Expected to find start of statement.",
-                                 self.current)
+        raise ParserError("Expected to find start of statement.",
+                          self.current)
 
     # PRINT "COMMA",SEPARATED,7154
     def parse_print(self, line_id: int) -> PrintStatement:
@@ -110,8 +101,8 @@ def parse_print(self, line_id: int) -> PrintStatement:
                 printables.append(expression)
                 last_col = expression.col_end
             else:
-                raise Parser.ParserError("Only strings and numeric expressions "
-                                         "allowed in print list.", self.current)
+                raise ParserError("Only strings and numeric expressions "
+                                  "allowed in print list.", self.current)
             # Comma means there's more to print
             if not self.out_of_tokens and self.current.kind is TokenType.COMMA:
                 self.consume(TokenType.COMMA)
@@ -166,15 +157,15 @@ def parse_return(self, line_id: int) -> ReturnStatement:
     # NUMERIC_EXPRESSION BOOLEAN_OPERATOR NUMERIC_EXPRESSION
     def parse_boolean_expression(self) -> BooleanExpression:
         left = self.parse_numeric_expression()
-        if self.current.kind in [TokenType.GREATER, TokenType.GREATER_EQUAL, TokenType.EQUAL,
-                                 TokenType.LESS, TokenType.LESS_EQUAL, TokenType.NOT_EQUAL]:
+        if self.current.kind in {TokenType.GREATER, TokenType.GREATER_EQUAL, TokenType.EQUAL,
+                                 TokenType.LESS, TokenType.LESS_EQUAL, TokenType.NOT_EQUAL}:
             operator = self.consume(self.current.kind)
             right = self.parse_numeric_expression()
             return BooleanExpression(line_num=left.line_num,
                                      col_start=left.col_start, col_end=right.col_end,
                                      operator=operator.kind, left_expr=left, right_expr=right)
-        raise Parser.ParserError(f"Expected boolean operator but found "
-                                 f"{self.current.kind}.", self.current)
+        raise ParserError(f"Expected boolean operator but found "
+                          f"{self.current.kind}.", self.current)
 
     def parse_numeric_expression(self) -> NumericExpression:
         left = self.parse_term()
@@ -235,7 +226,7 @@ def parse_factor(self) -> NumericExpression:
             self.consume(TokenType.OPEN_PAREN)
             expression = self.parse_numeric_expression()
             if self.current.kind is not TokenType.CLOSE_PAREN:
-                raise Parser.ParserError("Expected matching close parenthesis.", self.current)
+                raise ParserError("Expected matching close parenthesis.", self.current)
             self.consume(TokenType.CLOSE_PAREN)
             return expression
         elif self.current.kind is TokenType.MINUS:
@@ -244,4 +235,4 @@ def parse_factor(self) -> NumericExpression:
             return UnaryOperation(line_num=minus.line_num,
                                   col_start=minus.col_start, col_end=expression.col_end,
                                   operator=TokenType.MINUS, expr=expression)
-        raise Parser.ParserError("Unexpected token in numeric expression.", self.current)
+        raise ParserError("Unexpected token in numeric expression.", self.current)

tests/test_brainfuck.py

@@ -20,6 +20,7 @@
 import unittest
 import sys
 import os
+from pathlib import Path
 from io import StringIO
 from Brainfuck.brainfuck import Brainfuck
 
@@ -37,7 +38,7 @@ class BrainfuckTestCase(unittest.TestCase):
     def setUp(self) -> None:
         # Change working directory to this file so we can easily access
         # the Examples directory where the test Brainfuck code resides
-        os.chdir(os.path.dirname(os.path.abspath(__file__)))
+        os.chdir(Path(__file__).resolve().parent)
 
     def test_hello_world(self):
         program_output = run("../Brainfuck/Examples/hello_world_verbose.bf")

tests/test_knn.py

@@ -19,6 +19,7 @@
 import unittest
 import os
 import csv
+from pathlib import Path
 from KNN.knn import KNN
 from KNN.fish import Fish
 from KNN.digit import Digit
@@ -27,7 +28,7 @@
 class FishTestCase(unittest.TestCase):
     def setUp(self) -> None:
         # Change working directory to this file to get datasets
-        os.chdir(os.path.dirname(os.path.abspath(__file__)))
+        os.chdir(Path(__file__).resolve().parent)
 
     def test_nearest(self):
         k: int = 3

tests/test_nanobasic.py

@@ -20,6 +20,7 @@
 import unittest
 import sys
 import os
+from pathlib import Path
 from io import StringIO
 from NanoBASIC.executioner import execute
 
@@ -37,7 +38,7 @@ class NanoBASICTestCase(unittest.TestCase):
     def setUp(self) -> None:
         # Change working directory to this file so we can easily access
         # the Examples directory where the test NanoBASIC code resides
-        os.chdir(os.path.dirname(os.path.abspath(__file__)))
+        os.chdir(Path(__file__).resolve().parent)
 
     def test_print1(self):
         program_output = run("../NanoBASIC/Examples/print1.bas")

tests/test_nesemulator.py

@@ -18,6 +18,7 @@
 # Tries running multiple different tests to verify the correctness of our emulator.
 import unittest
 import os
+from pathlib import Path
 from NESEmulator.cpu import CPU
 from NESEmulator.ppu import PPU
 from NESEmulator.rom import ROM
@@ -27,7 +28,7 @@ class CPUTestCase(unittest.TestCase):
     def setUp(self) -> None:
         # Change working directory to this file so we can easily access
         # the Tests directory where the test ROMs and logs reside
-        os.chdir(os.path.dirname(os.path.abspath(__file__)))
+        os.chdir(Path(__file__).resolve().parent)
 
     def test_nes_test(self):
         # Create machinery that we are testing