commit 8a335a70206b19e36934a146ff38cadeef5c4675
Author: Zevaryx <zevaryx@gmail.com>
Date:   Wed May 5 17:37:20 2021 -0600

    Inital build with AutoCI/CD

diff --git a/.gitignore b/.gitignore
new file mode 100644
index 0000000..a81c8ee
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1,138 @@
+# Byte-compiled / optimized / DLL files
+__pycache__/
+*.py[cod]
+*$py.class
+
+# C extensions
+*.so
+
+# Distribution / packaging
+.Python
+build/
+develop-eggs/
+dist/
+downloads/
+eggs/
+.eggs/
+lib/
+lib64/
+parts/
+sdist/
+var/
+wheels/
+share/python-wheels/
+*.egg-info/
+.installed.cfg
+*.egg
+MANIFEST
+
+# PyInstaller
+#  Usually these files are written by a python script from a template
+#  before PyInstaller builds the exe, so as to inject date/other infos into it.
+*.manifest
+*.spec
+
+# Installer logs
+pip-log.txt
+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
+*.pot
+
+# Django stuff:
+*.log
+local_settings.py
+db.sqlite3
+db.sqlite3-journal
+
+# Flask stuff:
+instance/
+.webassets-cache
+
+# Scrapy stuff:
+.scrapy
+
+# Sphinx documentation
+docs/_build/
+
+# PyBuilder
+.pybuilder/
+target/
+
+# Jupyter Notebook
+.ipynb_checkpoints
+
+# IPython
+profile_default/
+ipython_config.py
+
+# pyenv
+#   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 stuff
+celerybeat-schedule
+celerybeat.pid
+
+# SageMath parsed files
+*.sage.py
+
+# Environments
+.env
+.venv
+env/
+venv/
+ENV/
+env.bak/
+venv.bak/
+
+# Spyder project settings
+.spyderproject
+.spyproject
+
+# Rope project settings
+.ropeproject
+
+# mkdocs documentation
+/site
+
+# mypy
+.mypy_cache/
+.dmypy.json
+dmypy.json
+
+# Pyre type checker
+.pyre/
+
+# pytype static type analyzer
+.pytype/
+
+# Cython debug symbols
+cython_debug/
diff --git a/.gitlab-ci.yml b/.gitlab-ci.yml
new file mode 100644
index 0000000..297abbe
--- /dev/null
+++ b/.gitlab-ci.yml
@@ -0,0 +1,11 @@
+image: python:rc
+cache:
+  paths:
+    - ~/.cache/pip/
+
+before_script:
+  - python -V
+
+tests:
+  script:
+    - python -m unittest discover tests
diff --git a/calculator/__init__.py b/calculator/__init__.py
new file mode 100644
index 0000000..e69de29
diff --git a/calculator/interpreter.py b/calculator/interpreter.py
new file mode 100644
index 0000000..9607508
--- /dev/null
+++ b/calculator/interpreter.py
@@ -0,0 +1,51 @@
+from .nodes import *
+from .values import Number
+
+
+class Interpreter:
+    def visit(self, node):
+        method_name = f"visit_{type(node).__name__}"
+        method = getattr(self, method_name)
+        return method(node)
+
+    def visit_NumberNode(self, node):
+        return Number(node.value)
+
+    def visit_AddNode(self, node):
+        return Number(
+            self.visit(node.node_a).value + self.visit(node.node_b).value
+        )
+
+    def visit_SubtractNode(self, node):
+        return Number(
+            self.visit(node.node_a).value - self.visit(node.node_b).value
+        )
+
+    def visit_MultiplyNode(self, node):
+        return Number(
+            self.visit(node.node_a).value * self.visit(node.node_b).value
+        )
+
+    def visit_DivideNode(self, node):
+        try:
+            return Number(
+                self.visit(node.node_a).value / self.visit(node.node_b).value
+            )
+        except:
+            raise Exception("Runtime Math Error")
+
+    def visit_PowerNode(self, node):
+        return Number(
+            self.visit(node.node_a).value ** self.visit(node.node_b).value
+        )
+
+    def visit_ModuloNode(self, node):
+        return Number(
+            self.visit(node.node_a).value % self.visit(node.node_b).value
+        )
+
+    def visit_PlusNode(self, node):
+        return self.visit(node.node)
+
+    def visit_MinusNode(self, node):
+        return Number(-self.visit(node.node).value)
diff --git a/calculator/lexer.py b/calculator/lexer.py
new file mode 100644
index 0000000..6c5e385
--- /dev/null
+++ b/calculator/lexer.py
@@ -0,0 +1,77 @@
+from .tokens import Token, TokenType
+from string import digits
+
+WHITESPACE = " \r\n\t"
+
+
+class Lexer:
+    def __init__(self, text):
+        self.text = iter(text)
+        self.advance()
+
+    def advance(self):
+        try:
+            self.current_char = next(self.text)
+        except StopIteration:
+            self.current_char = None
+
+    def generate_tokens(self):
+        while self.current_char is not None:
+            match self.current_char:
+                case x if x in WHITESPACE:
+                    self.advance()
+                case x if x in digits or x == ".":
+                    yield self.generate_number()
+                case "+":
+                    self.advance()
+                    yield Token(TokenType.PLUS)
+                case "-":
+                    self.advance()
+                    yield Token(TokenType.MINUS)
+                case "*":
+                    self.advance()
+                    yield Token(TokenType.MULTIPLY)
+                case "/":
+                    self.advance()
+                    yield Token(TokenType.DIVIDE)
+                case "(":
+                    self.advance()
+                    yield Token(TokenType.LPAREN)
+                case ")":
+                    self.advance()
+                    yield Token(TokenType.RPAREN)
+                case "^":
+                    self.advance()
+                    yield Token(TokenType.POWER)
+                case "%":
+                    self.advance()
+                    yield Token(TokenType.MODULO)
+                case _:
+                    raise Exception(f"Illegal Character: '{self.current_char}'")
+
+    def generate_number(self):
+        decimal_pt_count = 0
+        number_str = self.current_char
+        self.advance()
+
+        while self.current_char is not None and (
+            self.current_char == "." or self.current_char in digits
+        ):
+            if self.current_char == ".":
+                decimal_pt_count += 1
+                if decimal_pt_count > 1:
+                    break
+
+            number_str += self.current_char
+            self.advance()
+
+        if number_str.startswith("."):
+            number_str = "0" + number_str
+
+        if number_str.endswith("."):
+            number_str += "0"
+
+        return Token(
+            TokenType.NUMBER,
+            float(number_str) if "." in number_str else int(number_str),
+        )
diff --git a/calculator/nodes.py b/calculator/nodes.py
new file mode 100644
index 0000000..132d9a9
--- /dev/null
+++ b/calculator/nodes.py
@@ -0,0 +1,79 @@
+from dataclasses import dataclass
+
+
+@dataclass
+class NumberNode:
+    value: float | int
+
+    def __repr__(self):
+        return str(self.value)
+
+
+@dataclass
+class AddNode:
+    node_a: any
+    node_b: any
+
+    def __repr__(self):
+        return f"({self.node_a} + {self.node_b})"
+
+
+@dataclass
+class SubtractNode:
+    node_a: any
+    node_b: any
+
+    def __repr__(self):
+        return f"({self.node_a} - {self.node_b})"
+
+
+@dataclass
+class MultiplyNode:
+    node_a: any
+    node_b: any
+
+    def __repr__(self):
+        return f"({self.node_a} * {self.node_b})"
+
+
+@dataclass
+class DivideNode:
+    node_a: any
+    node_b: any
+
+    def __repr__(self):
+        return f"({self.node_a} / {self.node_b})"
+
+
+@dataclass
+class PowerNode:
+    node_a: any
+    node_b: any
+
+    def __repr__(self):
+        return f"({self.node_a} ^ {self.node_b})"
+
+
+@dataclass
+class ModuloNode:
+    node_a: any
+    node_b: any
+
+    def __repr__(self):
+        return f"({self.node_a} % {self.node_b})"
+
+
+@dataclass
+class PlusNode:
+    node: any
+
+    def __repr__(self):
+        return f"(+{self.node})"
+
+
+@dataclass
+class MinusNode:
+    node: any
+
+    def __repr__(self):
+        return f"(-{self.node})"
diff --git a/calculator/parser_.py b/calculator/parser_.py
new file mode 100644
index 0000000..737f219
--- /dev/null
+++ b/calculator/parser_.py
@@ -0,0 +1,94 @@
+from .tokens import TokenType
+from .nodes import *
+
+
+class Parser:
+    def __init__(self, tokens):
+        self.tokens = iter(tokens)
+        self.advance()
+
+    def raise_error(self, e = None):
+        if e:
+            raise Exception(f"Error: {e}")
+        raise Exception("Invalid syntax")
+
+    def advance(self):
+        try:
+            self.current_token = next(self.tokens)
+        except StopIteration:
+            self.current_token = None
+
+    def parse(self):
+        if self.current_token is None:
+            return
+
+        result = self.expr()
+
+        if self.current_token is not None:
+            self.raise_error("Current token is not None")
+
+        return result
+
+    def expr(self):
+        result = self.term()
+        while self.current_token is not None and self.current_token.type in (
+            TokenType.PLUS,
+            TokenType.MINUS,
+        ):
+            match self.current_token.type:
+                case TokenType.PLUS:
+                    self.advance()
+                    result = AddNode(result, self.term())
+                case TokenType.MINUS:
+                    self.advance()
+                    result = SubtractNode(result, self.term())
+
+        return result
+
+    def term(self):
+        result = self.factor()
+
+        while self.current_token is not None and self.current_token.type in (
+            TokenType.MULTIPLY,
+            TokenType.DIVIDE,
+            TokenType.POWER,
+            TokenType.MODULO,
+        ):
+            match self.current_token.type:
+                case TokenType.MULTIPLY:
+                    self.advance()
+                    result = MultiplyNode(result, self.factor())
+                case TokenType.DIVIDE:
+                    self.advance()
+                    result = DivideNode(result, self.factor())
+                case TokenType.POWER:
+                    self.advance()
+                    result = PowerNode(result, self.factor())
+                case TokenType.MODULO:
+                    self.advance()
+                    result = ModuloNode(result, self.factor())
+
+        return result
+
+    def factor(self):
+        token = self.current_token
+
+        match token.type:
+            case TokenType.LPAREN:
+                self.advance()
+                result = self.expr()
+                if self.current_token.type != TokenType.RPAREN:
+                    self.raise_error()
+                self.advance()
+                return result
+            case TokenType.NUMBER:
+                self.advance()
+                return NumberNode(token.value)
+            case TokenType.PLUS:
+                self.advance()
+                return PlusNode(self.factor())
+            case TokenType.MINUS:
+                self.advance()
+                return MinusNode(self.factor())
+
+        self.raise_error("Invalid factor token")
diff --git a/calculator/tokens.py b/calculator/tokens.py
new file mode 100644
index 0000000..48e3a0f
--- /dev/null
+++ b/calculator/tokens.py
@@ -0,0 +1,23 @@
+from enum import Enum
+from dataclasses import dataclass
+
+
+class TokenType(Enum):
+    NUMBER = 0
+    PLUS = 1
+    MINUS = 2
+    MULTIPLY = 3
+    DIVIDE = 4
+    LPAREN = 5
+    RPAREN = 6
+    POWER = 7
+    MODULO = 8
+
+
+@dataclass
+class Token:
+    type: TokenType
+    value: any = None
+
+    def __repr__(self):
+        return self.type.name + (f":{self.value}" if self.value else "")
diff --git a/calculator/values.py b/calculator/values.py
new file mode 100644
index 0000000..2b54301
--- /dev/null
+++ b/calculator/values.py
@@ -0,0 +1,9 @@
+from dataclasses import dataclass
+
+
+@dataclass
+class Number:
+    value: int | float
+
+    def __repr__(self):
+        return str(self.value)
diff --git a/main.py b/main.py
new file mode 100644
index 0000000..7518527
--- /dev/null
+++ b/main.py
@@ -0,0 +1,25 @@
+import sys
+from calculator.interpreter import Interpreter
+from calculator.lexer import Lexer
+from calculator.parser_ import Parser
+
+if __name__ == "__main__":
+    MIN_PYTHON = (3, 10)
+
+    if sys.version_info < MIN_PYTHON:
+        sys.exit("Python {}.{} or later is required".format(*MIN_PYTHON))
+
+    while True:
+        try:
+            text = input(">> ")
+            lexer = Lexer(text)
+            tokens = lexer.generate_tokens()
+            parser = Parser(tokens)
+            tree = parser.parse()
+            if not tree:
+                continue
+            interpreter = Interpreter()
+            value = interpreter.visit(tree)
+            print(value)
+        except Exception as e:
+            print(e)
diff --git a/tests/test_interpreter.py b/tests/test_interpreter.py
new file mode 100644
index 0000000..382fdd6
--- /dev/null
+++ b/tests/test_interpreter.py
@@ -0,0 +1,59 @@
+import unittest
+from calculator.nodes import (
+    NumberNode,
+    AddNode,
+    SubtractNode,
+    MultiplyNode,
+    DivideNode,
+    PowerNode,
+    ModuloNode,
+)
+from calculator.interpreter import Interpreter
+from calculator.values import Number
+
+
+class TestInterpreter(unittest.TestCase):
+    def test_numbers(self):
+        val = Interpreter().visit(NumberNode(42))
+        self.assertEqual(val, Number(42))
+
+    def test_individual_operations(self):
+        val = Interpreter().visit(AddNode(NumberNode(21), NumberNode(21)))
+        self.assertEqual(val, Number(42))
+
+        val = Interpreter().visit(SubtractNode(NumberNode(21), NumberNode(21)))
+        self.assertEqual(val, Number(0))
+
+        val = Interpreter().visit(MultiplyNode(NumberNode(21), NumberNode(21)))
+        self.assertEqual(val, Number(441))
+
+        val = Interpreter().visit(DivideNode(NumberNode(21), NumberNode(21)))
+        self.assertEqual(val, Number(1))
+
+        val = Interpreter().visit(PowerNode(NumberNode(21), NumberNode(21)))
+        self.assertEqual(val, Number(5842587018385982521381124421))
+
+        val = Interpreter().visit(ModuloNode(NumberNode(21), NumberNode(21)))
+        self.assertEqual(val, Number(0))
+
+        with self.assertRaises(Exception):
+            Interpreter().visit(DivideNode(NumberNode(42), NumberNode(0)))
+
+    def test_full_expression(self):
+        tree = ModuloNode(
+            SubtractNode(
+                AddNode(
+                    PowerNode(NumberNode(10), NumberNode(2)),
+                    AddNode(
+                        DivideNode(NumberNode(21), NumberNode(7)),
+                        NumberNode(7),
+                    ),
+                ),
+                MultiplyNode(NumberNode(5), NumberNode(2)),
+            ),
+            NumberNode(100),
+        )
+
+        result = Interpreter().visit(tree)
+
+        self.assertEqual(result, Number(0.0))
diff --git a/tests/test_lexer.py b/tests/test_lexer.py
new file mode 100644
index 0000000..b69ffae
--- /dev/null
+++ b/tests/test_lexer.py
@@ -0,0 +1,75 @@
+import unittest
+from calculator.lexer import Lexer
+from calculator.tokens import Token, TokenType
+
+
+class TestLexer(unittest.TestCase):
+    def test_empty(self):
+        tokens = list(Lexer("").generate_tokens())
+        self.assertEqual(tokens, [])
+
+    def test_whitespace(self):
+        tokens = list(Lexer("\t\n \t\t\n\n\r\r").generate_tokens())
+        self.assertEqual(tokens, [])
+
+    def test_numbers(self):
+        tokens = list(Lexer("123 123.456 123. .456 .").generate_tokens())
+        self.assertEqual(
+            tokens,
+            [
+                Token(TokenType.NUMBER, 123),
+                Token(TokenType.NUMBER, 123.456),
+                Token(TokenType.NUMBER, 123.0),
+                Token(TokenType.NUMBER, 0.456),
+                Token(TokenType.NUMBER, 0.0),
+            ],
+        )
+
+    def test_operators(self):
+        tokens = list(Lexer("+-*/^%").generate_tokens())
+        self.assertEqual(
+            tokens,
+            [
+                Token(TokenType.PLUS),
+                Token(TokenType.MINUS),
+                Token(TokenType.MULTIPLY),
+                Token(TokenType.DIVIDE),
+                Token(TokenType.POWER),
+                Token(TokenType.MODULO),
+            ],
+        )
+
+    def test_parens(self):
+        tokens = list(Lexer("()").generate_tokens())
+        self.assertEqual(
+            tokens, [Token(TokenType.LPAREN), Token(TokenType.RPAREN)]
+        )
+
+    def test_all(self):
+        tokens = list(
+            Lexer("(10 ^ 2 + (21 / 7 + 7) - 5 * 2) % 100").generate_tokens()
+        )
+        self.assertEqual(
+            tokens,
+            [
+                Token(TokenType.LPAREN),
+                Token(TokenType.NUMBER, 10),
+                Token(TokenType.POWER),
+                Token(TokenType.NUMBER, 2),
+                Token(TokenType.PLUS),
+                Token(TokenType.LPAREN),
+                Token(TokenType.NUMBER, 21),
+                Token(TokenType.DIVIDE),
+                Token(TokenType.NUMBER, 7),
+                Token(TokenType.PLUS),
+                Token(TokenType.NUMBER, 7),
+                Token(TokenType.RPAREN),
+                Token(TokenType.MINUS),
+                Token(TokenType.NUMBER, 5),
+                Token(TokenType.MULTIPLY),
+                Token(TokenType.NUMBER, 2),
+                Token(TokenType.RPAREN),
+                Token(TokenType.MODULO),
+                Token(TokenType.NUMBER, 100),
+            ],
+        )
diff --git a/tests/test_parser.py b/tests/test_parser.py
new file mode 100644
index 0000000..d43c105
--- /dev/null
+++ b/tests/test_parser.py
@@ -0,0 +1,114 @@
+import unittest
+from calculator.tokens import Token, TokenType
+from calculator.parser_ import Parser
+from calculator.nodes import (
+    NumberNode,
+    AddNode,
+    SubtractNode,
+    MultiplyNode,
+    DivideNode,
+    PowerNode,
+    ModuloNode,
+)
+
+
+class TestParser(unittest.TestCase):
+    def test_empty(self):
+        tokens = []
+        node = Parser(tokens).parse()
+        self.assertEqual(node, None)
+
+    def test_numbers(self):
+        tokens = [Token(TokenType.NUMBER, 100)]
+        node = Parser(tokens).parse()
+        self.assertEqual(node, NumberNode(100))
+
+    def test_individual_operations(self):
+        tokens = [
+            Token(TokenType.NUMBER, 21),
+            Token(TokenType.PLUS),
+            Token(TokenType.NUMBER, 23),
+        ]
+        node = Parser(tokens).parse()
+        self.assertEqual(node, AddNode(NumberNode(21), NumberNode(23)))
+
+        tokens = [
+            Token(TokenType.NUMBER, 21),
+            Token(TokenType.MINUS),
+            Token(TokenType.NUMBER, 23),
+        ]
+        node = Parser(tokens).parse()
+        self.assertEqual(node, SubtractNode(NumberNode(21), NumberNode(23)))
+
+        tokens = [
+            Token(TokenType.NUMBER, 21),
+            Token(TokenType.MULTIPLY),
+            Token(TokenType.NUMBER, 23),
+        ]
+        node = Parser(tokens).parse()
+        self.assertEqual(node, MultiplyNode(NumberNode(21), NumberNode(23)))
+
+        tokens = [
+            Token(TokenType.NUMBER, 21),
+            Token(TokenType.DIVIDE),
+            Token(TokenType.NUMBER, 23),
+        ]
+        node = Parser(tokens).parse()
+        self.assertEqual(node, DivideNode(NumberNode(21), NumberNode(23)))
+
+        tokens = [
+            Token(TokenType.NUMBER, 21),
+            Token(TokenType.POWER),
+            Token(TokenType.NUMBER, 23),
+        ]
+        node = Parser(tokens).parse()
+        self.assertEqual(node, PowerNode(NumberNode(21), NumberNode(23)))
+
+        tokens = [
+            Token(TokenType.NUMBER, 21),
+            Token(TokenType.MODULO),
+            Token(TokenType.NUMBER, 23),
+        ]
+        node = Parser(tokens).parse()
+        self.assertEqual(node, ModuloNode(NumberNode(21), NumberNode(23)))
+
+    def test_full_expression(self):
+        tokens = [
+            Token(TokenType.LPAREN),
+            Token(TokenType.NUMBER, 10),
+            Token(TokenType.POWER),
+            Token(TokenType.NUMBER, 2),
+            Token(TokenType.PLUS),
+            Token(TokenType.LPAREN),
+            Token(TokenType.NUMBER, 21),
+            Token(TokenType.DIVIDE),
+            Token(TokenType.NUMBER, 7),
+            Token(TokenType.PLUS),
+            Token(TokenType.NUMBER, 7),
+            Token(TokenType.RPAREN),
+            Token(TokenType.MINUS),
+            Token(TokenType.NUMBER, 5),
+            Token(TokenType.MULTIPLY),
+            Token(TokenType.NUMBER, 2),
+            Token(TokenType.RPAREN),
+            Token(TokenType.MODULO),
+            Token(TokenType.NUMBER, 100),
+        ]
+
+        node = Parser(tokens).parse()
+        self.assertEqual(
+            node,
+            ModuloNode(
+                SubtractNode(
+                    AddNode(
+                        PowerNode(NumberNode(10), NumberNode(2)),
+                        AddNode(
+                            DivideNode(NumberNode(21), NumberNode(7)),
+                            NumberNode(7),
+                        ),
+                    ),
+                    MultiplyNode(NumberNode(5), NumberNode(2)),
+                ),
+                NumberNode(100),
+            ),
+        )