Implemented interpreter pattern.

This commit is contained in:
tylerlaberge
2016-08-14 13:04:14 -04:00
parent d19b902285
commit 3c39f908cf
2 changed files with 54 additions and 66 deletions

View File

@@ -6,6 +6,11 @@ class Context(object):
Context class as part of the Interpreter design pattern.
"""
def __init__(self, in_data):
"""
Initialize a new Context class.
@param in_data: The starting input of this context.
"""
self.in_data = in_data
self.out_data = None
@@ -47,7 +52,7 @@ class TerminalExpression(Expression, metaclass=ABCMeta):
"""
Initialize a new TerminalExpression instance.
@param literal: A literal representing this TerminalExpression.
@param literal: A literal value representing this TerminalExpression.
"""
self.literal = literal

View File

@@ -69,6 +69,40 @@ class ExpressionTestCase(TestCase):
self.assertEquals('FOO', self.context.out_data)
class TerminalExpressionTestCase(TestCase):
"""
Unit testing class for the TerminalExpression class.
"""
def setUp(self):
"""
Initialize testing data.
"""
class ConcreteTerminal(TerminalExpression):
def interpret(self, context):
return self.literal
self.concrete_terminal_class = ConcreteTerminal
def test_init(self):
"""
Test the __init__ method.
@raise AssertionError: If the test fails.
"""
terminal = self.concrete_terminal_class('foo')
self.assertEquals('foo', terminal.literal)
def test_interpret(self):
"""
Test the interpret method.
@raise AssertionError: If the test fails.
"""
terminal = self.concrete_terminal_class('bar')
self.assertEquals('bar', terminal.interpret(Context('')))
class NonTerminalExpressionTestCase(TestCase):
"""
Unit testing class for the NonTerminalExpression class.
@@ -82,9 +116,10 @@ class NonTerminalExpressionTestCase(TestCase):
def interpret(self, context):
return self.literal
class RomanExpression(NonTerminalExpression, metaclass=ABCMeta):
class RomanNonTerminalExpression(NonTerminalExpression, metaclass=ABCMeta):
def interpret(self, context):
if context.out_data is None:
context.out_data = 0
@@ -107,27 +142,23 @@ class NonTerminalExpressionTestCase(TestCase):
context.out_data += 1 * self.multiplier()
context.in_data = context.in_data[1:]
@abstractmethod
def one(self):
pass
return self.expressions['one'].interpret(None)
@abstractmethod
def four(self):
pass
return self.expressions['four'].interpret(None)
@abstractmethod
def five(self):
pass
return self.expressions['five'].interpret(None)
@abstractmethod
def nine(self):
pass
return self.expressions['nine'].interpret(None)
@abstractmethod
def multiplier(self):
pass
class ThousandExpression(RomanExpression):
class ThousandExpression(RomanNonTerminalExpression):
def __init__(self):
one_terminal = RomanTerminalExpression('M')
@@ -137,22 +168,10 @@ class NonTerminalExpressionTestCase(TestCase):
super().__init__(one=one_terminal, four=four_terminal, five=five_terminal, nine=nine_terminal)
def one(self):
return self.expressions['one'].interpret(None)
def four(self):
return self.expressions['four'].interpret(None)
def five(self):
return self.expressions['five'].interpret(None)
def nine(self):
return self.expressions['nine'].interpret(None)
def multiplier(self):
return 1000
class HundredExpression(RomanExpression):
class HundredExpression(RomanNonTerminalExpression):
def __init__(self):
one_terminal = RomanTerminalExpression('C')
@@ -162,22 +181,10 @@ class NonTerminalExpressionTestCase(TestCase):
super().__init__(one=one_terminal, four=four_terminal, five=five_terminal, nine=nine_terminal)
def one(self):
return self.expressions['one'].interpret(None)
def four(self):
return self.expressions['four'].interpret(None)
def five(self):
return self.expressions['five'].interpret(None)
def nine(self):
return self.expressions['nine'].interpret(None)
def multiplier(self):
return 100
class TenExpression(RomanExpression):
class TenExpression(RomanNonTerminalExpression):
def __init__(self):
one_terminal = RomanTerminalExpression('X')
@@ -187,22 +194,10 @@ class NonTerminalExpressionTestCase(TestCase):
super().__init__(one=one_terminal, four=four_terminal, five=five_terminal, nine=nine_terminal)
def one(self):
return self.expressions['one'].interpret(None)
def four(self):
return self.expressions['four'].interpret(None)
def five(self):
return self.expressions['five'].interpret(None)
def nine(self):
return self.expressions['nine'].interpret(None)
def multiplier(self):
return 10
class OneExpression(RomanExpression):
class OneExpression(RomanNonTerminalExpression):
def __init__(self):
one_terminal = RomanTerminalExpression('I')
@@ -212,18 +207,6 @@ class NonTerminalExpressionTestCase(TestCase):
super().__init__(one=one_terminal, four=four_terminal, five=five_terminal, nine=nine_terminal)
def one(self):
return self.expressions['one'].interpret(None)
def four(self):
return self.expressions['four'].interpret(None)
def five(self):
return self.expressions['five'].interpret(None)
def nine(self):
return self.expressions['nine'].interpret(None)
def multiplier(self):
return 1