class Calculator:
""" Very cool calculator class using all the other cool classes """
def __init__(self):
self.lexer = Lexer()
self.context = EvaluationContext()
self.builtins = ["exit", "debug", "help", "vars", "functions"]
self.debug = False
def main(self):
""" Main function. Who would have expected this? """
print("Welcome to {}.py v0.7".format(self.__class__.__name__))
print()
print("Note: Not every function will work with complex numbers.")
print("Note: use debug command to toggle debug mode (syntax tree output).")
print("Note: this version does not (yet?) support function definitions at runtime.")
#TODO: some mechanism to insert lambda function definitions at runtime?
print()
self.handle_builtin("help")
while True:
try:
print()
formula = input(">>> ")
if formula in self.builtins:
self.handle_builtin(formula)
continue
lexemes = self.lexer.lexe(formula)
parsed = Sum.parse(lexemes)
if len(lexemes) != 0:
raise ParserError("Formula did not parse completely," +
"remaining lexemes are: {}".format(lexemes))
if (self.debug):
print("Input was parsed as this simplified syntax tree:")
self.pretty_print(str(parsed))
result = parsed.evaluate(self.context)
self.context.set_variable("ans", result)
print(self.format_result(result))
except ParserError as e:
print("ParserError:", e)
continue
except LexerError as e:
print("LexerError:", e)
continue
except (EvaluationError, ValueError, TypeError) as e:
print("EvaluationError:", e)
continue
except (KeyboardInterrupt, EOFError):
print("Exiting.")
break
def pretty_print(self, tree, indent=4):
""" Very, very, very bad pretty print function.
I couldn't imagine a clean way to pretty print these syntax tree strings... """
cur_indent = 0
cur_line = ""
for i in range(len(tree) - 1):
if tree[i] in [":", "("]:
cur_line += tree[i]
cur_indent += indent
print(cur_line)
cur_line = " " * cur_indent
continue
if tree[i] == " ":
if cur_line == " " * len(cur_line):
continue #don't print empty lines
print(cur_line)
cur_line = " " * cur_indent
continue
if tree[i] in ["]", ")"]:
print(cur_line)
cur_indent -= indent
cur_line = " " * cur_indent + tree[i]
continue
cur_line += tree[i]
print(cur_line)
print(tree[-1])
def handle_builtin(self, builtin):
if builtin == "help":
print("Built-in commands:")
print(*self.builtins, sep=", ")
elif builtin == "exit":
raise EOFError
elif builtin == "vars":
variables = sorted(self.context.variables)
max_length = max([len(v) for v in variables]) + 1
print("There are currently {} known variables:".format(len(variables)))
print("(Constants are marked with [*])")
for key in variables:
print("{}:{}{}{}".format(key, " " * (max_length - len(key)),
self.format_result(self.context.get_variable(key)),
" [*]" if self.context.is_variable_constant(key) else ""))
elif builtin == "functions":
functions = sorted(self.context.functions)
print("There are currently {} supported functions:".format(len(functions)))
for key in functions:
string = "{}(".format(key)
function = self.context.functions[key]
maximum = function.arity if function.arity >= 0 else abs(function.arity) - 1
for i in range(maximum):
if i != 0:
string += ", "
string += chr(ord("a") + i)
if function.arity < -1:
string += ", *"
elif function.arity == -1:
string += "*"
string += ") => {}".format(self.context.functions[key].description)
print(string)
elif builtin == "debug":
self.debug = not self.debug
print("Debug mode turned {}".format("on" if self.debug else "off"))
def format_result(self, result):
if isinstance(result, complex):
string = str(result)
if string[0] == '(': #format: (a+bj)
return string[1:-1].replace('j', 'i')
else: #format: bj
return string.replace('j', 'i')
else:
return '{}'.format(result)
def __init__(self): self.lexer = Lexer() self.context = EvaluationContext() self.builtins = ["exit", "debug", "help", "vars", "functions"] self.debug = False
