Initial commit

.gitignore

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+# 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/
+pip-wheel-metadata/
+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
+.hypothesis/
+.pytest_cache/
+
+# Translations
+*.mo
+*.pot
+
+# Django stuff:
+*.log
+local_settings.py
+db.sqlite3
+
+# Flask stuff:
+instance/
+.webassets-cache
+
+# Scrapy stuff:
+.scrapy
+
+# Sphinx documentation
+docs/_build/
+
+# PyBuilder
+target/
+
+# Jupyter Notebook
+.ipynb_checkpoints
+
+# IPython
+profile_default/
+ipython_config.py
+
+# pyenv
+.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
+
+# celery beat schedule file
+celerybeat-schedule
+
+# 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/
+

constants.py

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+NUMBER = 'NUMBER'
+EOF = 'EOF'
+
+PLUS = 'PLUS'
+MINUS = 'MINUS'
+MUL = 'MUL'
+DIV = 'DIV'
+POW = 'POW'
+
+HEX = 'HEX'
+DEC = 'DEC'
+BIN = 'BIN'
+

interpreter.py

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+from constants import (
+	NUMBER, EOF,
+	PLUS, MINUS, MUL, DIV, POW,
+	HEX, DEC, BIN,
+)
+
+
+class Interpreter:
+	def __init__(self):
+		self.stack = []
+		self.mode = DEC
+		self.mode_func = float
+
+	def init_lexer(self, lexer):
+		self.lexer = lexer
+		self.current_token = self.lexer.get_next_token()
+
+	def eat(self, type):
+		if self.current_token.type == type:
+			self.current_token = self.lexer.get_next_token()
+		else:
+			raise Exception('Wrong token eaten')
+
+	def get_from_stack(self, pop=True):
+		if pop:
+			value = self.stack.pop()
+		else:
+			value = self.stack[-1]
+
+		if type(value) is str:
+			return self.ariables[value]
+
+		return value
+
+	def evaluate_operator(self, token):
+		if len(self.stack) < 2:
+			raise Exception('Needs at least 2 values on the stack')
+
+		right = self.get_from_stack()
+		left = self.get_from_stack()
+		self.stack.append(token.value(left, right))
+		self.eat(token.type)
+
+	def set_mode(self, token):
+		self.mode = token.type
+		self.mode_func = token.value
+
+	def parse(self, lexer):
+		self.init_lexer(lexer)
+		token = self.current_token
+
+		while token.type is not EOF:
+			if token.type in (PLUS, MINUS, MUL, DIV, POW):
+				self.evaluate_operator(token)
+			elif token.type == NUMBER:
+				self.stack.append(token.value)
+				self.eat(NUMBER)
+			elif token.type in (HEX, DEC, BIN):
+				self.set_mode(token)
+				self.eat(token.type)
+
+			token = self.current_token
+
+		return self.stack
+

lexer.py

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+import operator
+
+from token import Token
+from constants import (
+	NUMBER, EOF,
+	PLUS, MINUS, MUL, DIV, POW,
+	HEX, DEC, BIN,
+)
+
+
+class Lexer():
+	def __init__(self, text):
+		self.text = text
+		self.pos = 0
+		self.current_char = self.text[self.pos]
+
+	def error(self, value=None):
+		if value is None:
+			raise Exception(f'Unexpected character {self.current_char}')
+		else:
+			raise Exception(f'Unexpected token {value}')
+
+	def advance(self):
+		self.pos += 1
+
+		if self.pos > len(self.text) - 1:
+			self.current_char = None
+		else:
+			self.current_char = self.text[self.pos]
+
+	def number(self):
+		number = ''
+		while self.current_char is not None and (self.current_char.isdigit() or self.current_char == '.'):
+			number += self.current_char
+			self.advance()
+
+		return float(number)
+
+	def skip_whitespace(self):
+		while(self.current_char is not None and self.current_char.isspace()):
+			self.advance()
+
+	def get_next_token(self):
+		while self.current_char is not None:
+			if self.current_char.isspace():
+				self.skip_whitespace()
+				continue
+
+			elif self.current_char.isdigit():
+				return Token(NUMBER, self.number())
+
+			elif self.current_char == '+':
+				self.advance()
+				return Token(PLUS, operator.add)
+
+			elif self.current_char == '-':
+				self.advance()
+				return Token(MINUS, operator.sub)
+
+			elif self.current_char == '*':
+				self.advance()
+				return Token(MUL, operator.mul)
+
+			elif self.current_char == '/':
+				self.advance()
+				return Token(DIV, operator.truediv)
+
+			elif self.current_char == '^':
+				self.advance()
+				return Token(POW, operator.pow)
+
+			elif self.current_char and self.current_char.isalpha():
+				text = ''
+				while self.current_char and (self.current_char.isalpha() or self.current_char.isdigit() or self.current_char == '_'):
+					text += self.current_char
+					self.advance()
+
+				if text.lower() == 'hex':
+					return Token(HEX, hex)
+				elif text.lower() == 'dec':
+					return Token(DEC, float)
+				elif text.lower() == 'bin':
+					return Token(BIN, bin)
+				else:
+					self.error(text)
+
+			self.error()
+
+		return Token(EOF, None)
+

main.py

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+from lexer import Lexer
+from interpreter import Interpreter
+from constants import DEC
+
+
+def print_stack(interpreter, stack):
+	for item in stack:
+		if interpreter.mode == DEC and item.is_integer():
+			print(int(item))
+		else:
+			print(interpreter.mode_func(item))
+
+
+def main():
+	interpreter = Interpreter()
+
+	while True:
+		try:
+			text = input('> ')
+		except (EOFError, KeyboardInterrupt):
+			break
+
+		if not text:
+			continue
+
+		if text == 'exit':
+			break
+
+		lexer = Lexer(text)
+		try:
+			stack = interpreter.parse(lexer)
+		except Exception as exception:
+			print(exception)
+
+		print_stack(interpreter, stack)
+
+
+if __name__ == "__main__":
+	main()
+

token.py

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+class Token():
+	def __init__(self, type, value):
+		self.type = type
+		self.value = value
+
+	def __repr__(self):
+		return "<{} {}>".format(self.type, self.value)
+