Fix examples formatting issues and make them pep8 compliant

examples/calculator_client.py

@@ -7,25 +7,38 @@ import capnp
 
 import calculator_capnp
 
+
 class PowerFunction(calculator_capnp.Calculator.Function.Server):
+
     '''An implementation of the Function interface wrapping pow().  Note that
     we're implementing this on the client side and will pass a reference to
     the server.  The server will then be able to make calls back to the client.'''
 
     def call(self, params, **kwargs):
-        '''Note the **kwargs. This is very necessary to include, since protocols can add parameters over time. Also, by default, a _context variable is passed to all server methods. Read the docs for further explanation.'''
+        '''Note the **kwargs. This is very necessary to include, since
+        protocols can add parameters over time. Also, by default, a _context
+        variable is passed to all server methods, but you can also return
+        results directly as python objects, and they'll be added to the
+        results struct in the correct order'''
+
         return pow(params[0], params[1])
 
+
 def parse_args():
-    parser = argparse.ArgumentParser(usage='Connects to the Calculator server at the given address and does some RPCs')
+    parser = argparse.ArgumentParser(usage='Connects to the Calculator server \
+at the given address and does some RPCs')
     parser.add_argument("host", help="HOST:PORT")
 
     return parser.parse_args()
 
+
 def main(sock):
     client = capnp.TwoPartyClient(sock)
 
-    # Pass "calculator" to ez_restore (there's also a `restore` function that takes a struct or AnyPointer as an argument), and then cast the returned capability to it's proper type. This casting is due to capabilities not having a reference to their schema
+    # Pass "calculator" to ez_restore (there's also a `restore` function that
+    # takes a struct or AnyPointer as an argument), and then cast the returned
+    # capability to it's proper type. This casting is due to capabilities not
+    # having a reference to their schema
     calculator = client.ez_restore('calculator').cast_as(calculator_capnp.Calculator)
 
     '''Make a request that just evaluates the literal value 123.
@@ -40,14 +53,17 @@ def main(sock):
 
     print('Evaluating a literal... ', end="")
 
-    # Set up the request. Note the form is 'evaluate' + '_request', where 'evaluate' is the name of the method we want to call
+    # Set up the request. Note the form is 'evaluate' + '_request', where
+    # 'evaluate' is the name of the method we want to call
     request = calculator.evaluate_request()
     request.expression.literal = 123
 
     # Send it, which returns a promise for the result (without blocking).
     eval_promise = request.send()
 
-    # Using the promise, create a pipelined request to call read() on the returned object. Note that here we are using the shortened method call syntax read(), which is mostly just sugar for read_request().send()
+    # Using the promise, create a pipelined request to call read() on the
+    # returned object. Note that here we are using the shortened method call
+    # syntax read(), which is mostly just sugar for read_request().send()
     read_promise = eval_promise.value.read()
 
     # Now that we've sent all the requests, wait for the response.  Until this
@@ -94,7 +110,6 @@ def main(sock):
 
     print("PASS")
 
-
     '''Make a request to evaluate 4 * 6, then use the result in two more
     requests that add 3 and 5.
 
@@ -110,13 +125,12 @@ def main(sock):
     # Get the "multiply" function from the server.
     multiply = calculator.getOperator(op='multiply').func
 
-
     # Build the request to evaluate 4 * 6
     request = calculator.evaluate_request()
 
     multiply_call = request.expression.init("call")
     multiply_call.function = multiply
-    multiply_params = multiply_call.init("params", 2);
+    multiply_params = multiply_call.init("params", 2)
     multiply_params[0].literal = 4
     multiply_params[1].literal = 6
 
@@ -124,25 +138,25 @@ def main(sock):
 
     # Use the result in two calls that add 3 and add 5.
 
-    add3Request = calculator.evaluate_request()
+    add_3_request = calculator.evaluate_request()
-    add3Call = add3Request.expression.init("call")
+    add_3_call = add_3_request.expression.init("call")
-    add3Call.function = add
+    add_3_call.function = add
-    add3Params = add3Call.init("params", 2)
+    add_3_params = add_3_call.init("params", 2)
-    add3Params[0].previousResult = multiply_result
+    add_3_params[0].previousResult = multiply_result
-    add3Params[1].literal = 3
+    add_3_params[1].literal = 3
-    add3Promise = add3Request.send().value.read()
+    add_3_promise = add_3_request.send().value.read()
 
-    add5Request = calculator.evaluate_request()
+    add_5_request = calculator.evaluate_request()
-    add5Call = add5Request.expression.init("call")
+    add_5_call = add_5_request.expression.init("call")
-    add5Call.function = add
+    add_5_call.function = add
-    add5Params = add5Call.init("params", 2)
+    add_5_params = add_5_call.init("params", 2)
-    add5Params[0].previousResult = multiply_result
+    add_5_params[0].previousResult = multiply_result
-    add5Params[1].literal = 5
+    add_5_params[1].literal = 5
-    add5Promise = add5Request.send().value.read()
+    add_5_promise = add_5_request.send().value.read()
 
     # Now wait for the results.
-    assert add3Promise.wait().value == 27
+    assert add_3_promise.wait().value == 27
-    assert add5Promise.wait().value == 29
+    assert add_5_promise.wait().value == 29
 
     print("PASS")
 
@@ -168,16 +182,16 @@ def main(sock):
     request.paramCount = 2
 
     # Build the function body.
-    addCall = request.body.init("call")
+    add_call = request.body.init("call")
-    addCall.function = add
+    add_call.function = add
-    addParams = addCall.init("params", 2)
+    add_params = add_call.init("params", 2)
-    addParams[1].parameter = 1  # y
+    add_params[1].parameter = 1  # y
 
-    multiplyCall = addParams[0].init("call")
+    multiply_call = add_params[0].init("call")
-    multiplyCall.function = multiply
+    multiply_call.function = multiply
-    multiplyParams = multiplyCall.init("params", 2)
+    multiply_params = multiply_call.init("params", 2)
-    multiplyParams[0].parameter = 0 # x
+    multiply_params[0].parameter = 0  # x
-    multiplyParams[1].literal = 100
+    multiply_params[1].literal = 100
 
     f = request.send().func
 
@@ -186,45 +200,45 @@ def main(sock):
     request.paramCount = 1
 
     # Build the function body.
-    multiplyCall = request.body.init("call")
+    multiply_call = request.body.init("call")
-    multiplyCall.function = multiply
+    multiply_call.function = multiply
-    multiplyParams = multiplyCall.init("params", 2)
+    multiply_params = multiply_call.init("params", 2)
-    multiplyParams[1].literal = 2
+    multiply_params[1].literal = 2
 
-    fCall = multiplyParams[0].init("call")
+    f_call = multiply_params[0].init("call")
-    fCall.function = f
+    f_call.function = f
-    fParams = fCall.init("params", 2)
+    f_params = f_call.init("params", 2)
-    fParams[0].parameter = 0
+    f_params[0].parameter = 0
 
-    addCall = fParams[1].init("call")
+    add_call = f_params[1].init("call")
-    addCall.function = add
+    add_call.function = add
-    addParams = addCall.init("params", 2)
+    add_params = add_call.init("params", 2)
-    addParams[0].parameter = 0
+    add_params[0].parameter = 0
-    addParams[1].literal = 1
+    add_params[1].literal = 1
 
     g = request.send().func
 
     # OK, we've defined all our functions.  Now create our eval requests.
 
     # f(12, 34)
-    fEvalRequest = calculator.evaluate_request()
+    f_eval_request = calculator.evaluate_request()
-    fCall = fEvalRequest.expression.init("call")
+    f_call = f_eval_request.expression.init("call")
-    fCall.function = f
+    f_call.function = f
-    fParams = fCall.init("params", 2)
+    f_params = f_call.init("params", 2)
-    fParams[0].literal = 12
+    f_params[0].literal = 12
-    fParams[1].literal = 34
+    f_params[1].literal = 34
-    fEvalPromise = fEvalRequest.send().value.read()
+    f_eval_promise = f_eval_request.send().value.read()
 
     # g(21)
-    gEvalRequest = calculator.evaluate_request()
+    g_eval_request = calculator.evaluate_request()
-    gCall = gEvalRequest.expression.init("call")
+    g_call = g_eval_request.expression.init("call")
-    gCall.function = g
+    g_call.function = g
-    gCall.init('params', 1)[0].literal = 21
+    g_call.init('params', 1)[0].literal = 21
-    gEvalPromise = gEvalRequest.send().value.read()
+    g_eval_promise = g_eval_request.send().value.read()
 
     # Wait for the results.
-    assert fEvalPromise.wait().value == 1234
+    assert f_eval_promise.wait().value == 1234
-    assert gEvalPromise.wait().value == 4244
+    assert g_eval_promise.wait().value == 4244
 
     print("PASS")
 
@@ -250,16 +264,16 @@ def main(sock):
     # Build the eval request for 2^(4+5).
     request = calculator.evaluate_request()
 
-    powCall = request.expression.init("call")
+    pow_call = request.expression.init("call")
-    powCall.function = PowerFunction()
+    pow_call.function = PowerFunction()
-    powParams = powCall.init("params", 2)
+    pow_params = pow_call.init("params", 2)
-    powParams[0].literal = 2
+    pow_params[0].literal = 2
 
-    addCall = powParams[1].init("call")
+    add_call = pow_params[1].init("call")
-    addCall.function = add
+    add_call.function = add
-    addParams = addCall.init("params", 2)
+    add_params = add_call.init("params", 2)
-    addParams[0].literal = 4
+    add_params[0].literal = 4
-    addParams[1].literal = 5
+    add_params[1].literal = 5
 
     # Send the request and wait.
     response = request.send().value.read().wait()

examples/calculator_server.py

@@ -8,6 +8,7 @@ import capnp
 
 import calculator_capnp
 
+
 def readValue(value):
     '''Helper function to asynchronously call read() on a Calculator::Value and
     return a promise for the result.  (In the future, the generated code might
@@ -15,6 +16,7 @@ def readValue(value):
 
     return value.read().then(lambda result: result.value)
 
+
 def evaluateImpl(expression, params=None):
     '''Implementation of CalculatorImpl::evaluate(), also shared by
     FunctionImpl::call().  In the latter case, `params` are the parameter
@@ -22,17 +24,15 @@ def evaluateImpl(expression, params=None):
     empty list.'''
 
     which = expression.which()
+
     if which == 'literal':
-      return capnp.Promise(expression.literal)
+        return capnp.Promise(expression.literal)
     elif which == 'previousResult':
-      return readValue(expression.previousResult)
+        return readValue(expression.previousResult)
     elif which == 'parameter':
-      assert expression.parameter < len(params)
+        assert expression.parameter < len(params)
-      return capnp.Promise(params[expression.parameter])
+        return capnp.Promise(params[expression.parameter])
     elif which == 'call':
-        def then(vals):
-            ret =  func.call(vals).then(lambda result: result.value)
-            return ret
         call = expression.call
         func = call.function
 
@@ -41,14 +41,15 @@ def evaluateImpl(expression, params=None):
 
         joinedParams = capnp.join_promises(paramPromises)
         # When the parameters are complete, call the function.
-        ret = joinedParams.then(then)
+        ret = joinedParams.then(lambda vals: func.call(vals).then(lambda result: result.value))
 
         return ret
-
     else:
         raise ValueError("Unknown expression type: " + which)
 
+
 class ValueImpl(calculator_capnp.Calculator.Value.Server):
+
     "Simple implementation of the Calculator.Value Cap'n Proto interface."
 
     def __init__(self, value):
@@ -57,21 +58,29 @@ class ValueImpl(calculator_capnp.Calculator.Value.Server):
     def read(self, **kwargs):
         return self.value
 
+
 class FunctionImpl(calculator_capnp.Calculator.Function.Server):
+
     '''Implementation of the Calculator.Function Cap'n Proto interface, where the
     function is defined by a Calculator.Expression.'''
 
-    def __init__(self, paramCount, body, obj):
+    def __init__(self, paramCount, body):
         self.paramCount = paramCount
         self.body = body.as_builder()
-        self.obj = obj
 
     def call(self, params, _context, **kwargs):
+        '''Note that we're returning a Promise object here, and bypassing the
+        helper functionality that normally sets the results struct from the
+        returned object. Instead, we set _context.results directly inside of
+        another promise'''
+
         assert len(params) == self.paramCount
-        return evaluateImpl(self.body, params).then(lambda value: setattr(_context.results, 'value', value)) # using setattr because '=' is not allowed inside of lambdas
+        # using setattr because '=' is not allowed inside of lambdas
+        return evaluateImpl(self.body, params).then(lambda value: setattr(_context.results, 'value', value))
 
 
 class OperatorImpl(calculator_capnp.Calculator.Function.Server):
+
     '''Implementation of the Calculator.Function Cap'n Proto interface, wrapping
     basic binary arithmetic operators.'''
 
@@ -82,6 +91,7 @@ class OperatorImpl(calculator_capnp.Calculator.Function.Server):
         assert len(params) == 2
 
         op = self.op
+
         if op == 'add':
             return params[0] + params[1]
         elif op == 'subtract':
@@ -93,23 +103,25 @@ class OperatorImpl(calculator_capnp.Calculator.Function.Server):
         else:
             raise ValueError('Unknown operator')
 
+
 class CalculatorImpl(calculator_capnp.Calculator.Server):
+
     "Implementation of the Calculator Cap'n Proto interface."
 
     def evaluate(self, expression, _context, **kwargs):
         return evaluateImpl(expression).then(lambda value: setattr(_context.results, 'value', ValueImpl(value)))
 
     def defFunction(self, paramCount, body, _context, **kwargs):
-        return FunctionImpl(paramCount, body, _context)
+        return FunctionImpl(paramCount, body)
 
     def getOperator(self, op, **kwargs):
         return OperatorImpl(op)
 
+
 def parse_args():
-    parser = argparse.ArgumentParser(usage='''Runs the server bound to the given address/port
+    parser = argparse.ArgumentParser(usage='''Runs the server bound to the\
-ADDRESS may be '*' to bind to all local addresses.
+given address/port ADDRESS may be '*' to bind to all local addresses.\
-:PORT may be omitted to choose a port automatically.
+:PORT may be omitted to choose a port automatically. ''')
-''')
 
     parser.add_argument("address", help="ADDRESS[:PORT]")
 
@@ -117,6 +129,10 @@ ADDRESS may be '*' to bind to all local addresses.
 
 
 class CalcRestorer:
+
+    '''A RPC Restorer. This requires a `restore` function to be defined, and
+    will be passed in a SturdyRef by your client'''
+
     def __init__(self):
         self.calc = CalculatorImpl()
 
@@ -124,6 +140,7 @@ class CalcRestorer:
         assert ref.as_text() == 'calculator'
         return CalculatorImpl()
 
+
 def main():
     address = parse_args().address
 
@@ -131,7 +148,7 @@ def main():
         address, port = address.split(':')
         port = int(port)
     else:
-        port = random.randint(60000,61000)
+        port = random.randint(60000, 61000)
 
     if address == '*':
         address = ''
@@ -139,8 +156,8 @@ def main():
     print("Listening on port: {}".format(port))
 
     s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
-    s.bind((address,port)) 
+    s.bind((address, port))
-    s.listen(1) # service only 1 client at a time
+    s.listen(1)  # service only 1 client at a time
 
     while True:
         try: