function with another function as parameter

Question

I've created several functions

#generate .h file template for class
def generateHeaderClassTemplate(name):
    template = open('header.template', 'r')
    code = parseHeaderTemplate(template.read(), name)
    template.close()
    return code

#generate .cpp file template for class
def generateImplClassTemplate(name):
    template = open('class.template', 'r')
    code = parseImplTemplate(template.read(), name)
    template.close()
    return code

#generate main.cpp file template
def generateMainTemplate():
    template = open('main.template', 'r')
    code = parseMainTemplate(template.read())
    template.close()
    return code

But the problem is that they are all basically the same

1. open file
2. write there some function result
3. close file
4. return data

So I want to create some universal function which will have function as parameter, filename as parameter and parameter for the function. And then function like generateHeaderClassTemplate will be something like

def generateHeaderClassTemplate(name):
    return generateTemplate(parseHeaderTemplate, 'header.template', name)

Basically I want function like this

def generateTemplate(func, templateFile, name):
    template = open(templateFile, 'r')
    code = func(template.read(), name) #or code = func(template.read()) if name was not passed
    template.close()
    return code

But how to make it work as in comment I wrote - If I do not pass name - perform func(template.read()) and if I pass it - perform func(template.read(), name) ?

Answer 1

Using python optional arguments

http://www.diveintopython.net/power_of_introspection/optional_arguments.html

When you declare the function you can pass default values to arguments, so if you don't pass them into the function when you call it by default it will use those parameters, like this example:

def info(object, spacing=10, collapse=1):

spacing defaults to 10 and collapse to 1

Answer 2

You can use default value for the parameters:

def generateTemplate(func, templateFile, name=None):

this way you can use generateTemplate with or without a third argument:

generateTemplate(parseImplTemplate, 'f')
generateTemplate(parseMainTemplate, 'f', 'foo)

And in the generateTemplate definition, you can do something like:

def generateTemplate(func, templateFile, name=None):
    template = open(templateFile, 'r')
    if name:
        code = func(template.read(), name) 
    else:
        code = func(template.read())
    template.close()
    return code

Answer 3

Perhaps a default value to the parameter name would help you

def test(a, b = ""):
    print (a, b)

test ("hello")
test ("hello", "world")

Your template methids must always have the same prototype, generateTemplateFun(name="") but when calling them you can skip the name part making the code cleaner