How to configure Firefox programmatically

I reinstalled Ubuntu on my personal computer recently and I noticed that there are some things I don’t like about the default distribution. One of the things I noticed is that Firefox keeps asking me if I want it to remember my passwords, which I don’t.

I know that I can go to settings and disable this feature, but I wanted to learn how to do it programmatically, so in the future I can just run a script and have Firefox work the way I want.

Preferences

There is documentation explaining how preferences work for mozilla projects, but it’s a little hard to understand how to exactly do what I wanted to do.

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Virtual functions in C++

If you are not familiar with Inheritance, I recommend you read my short article about inheritance first.

One of the features of Object Oriented Programming is Polymorphism. Virtual functions in C++ allow developers to achieve run-time polymorphism by overwriting methods of a base class.

In my article about inheritance, I showed how we can create classes that inherit from a base (or parent) class. Something similar to the following:

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class Greeter {
 public:
  void talk() {
    std::cout << "hello" << std::endl;
  }
};

class SpanishGreeter : public Greeter {
 public:
  void talk() {
    std::cout << "hola" << std::endl;
  }
};
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Inheritance in C++

Inheritance is a feature of Object Oriented Programming that allows programmers to create classes based on other classes. A class that inherits from another class will have the same behavior as the parent class unless it is overwritten.

Let’s say we have a class:

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class Greeter {
 public:
  void talk() {
    std::cout << greeting_ << std::endl;
  }

 protected:
  std::string greeting_ = "hello";
};
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Enums in C++

Enumerations are useful when we want to have a custom type, that can only have a limited number of values. For example:

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enum Mode {
  EASY,
  MEDIUM,
  HARD
};

We can create variables of type enum that can only have one of the previously defined values:

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Mode userMode = EASY;
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C-style arrays vs std::array

In this post I’m going to talk about the advantages of using std::array vs a c-style array whenever it is possible to do so.

C-style arrays

Let’s start by remembering what a c-style array is.

In C and C++ we can create an array of ints like this:

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int arr[3];
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Creating a C++ package with Conan

In the past I wrote an article that explains how to consume packages using Conan. In this article I’m going to explain how we can create our own packages with Conan.

I’m going to create a simple cpp library and make a conan package out of it.

Sample package

The first step is to create a folder for the library:

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mkdir MyLib
cd MyLib
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Variadic templates / functions in C++

A variadic function is a function that can take a variable number of arguments.

I have used variadic functions in previous posts, but I have not explained how they work. This post will cover that.

C-style variadic functions

C++ supports the C-like syntax for writing variadic fuctions.

Let’s say we want to write a function that adds numbers together. If we wanted to write a function that adds two numbers, we could do it easily:

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int add(int a, int b) {
  return a + b;
}
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Passing functions as arguments in C++

Using functions that take functions

There are times, when it is convenient to have a function receive a function as an argument. This technique can be seen in the standard C++ library. As an example, std::transform can be used to create a series of values based on other values:

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#include <vector>
#include <algorithm>
#include <iostream>

int makeNumbersBig(int small) {
  return small * 10;
}

int main() {
  std::vector<int> numbers{1, 2, 3}; // numbers has 3 values: 1, 2, 3
  std::vector<int> bigNumbers(3); // bigNumbers has 3 values, default
                                  // initialized: 0, 0, 0

  // Starting at numbers.begin() and until numbers.end(), execute
  // makeNumbersBig and store the result in bigNumbers
  std::transform(
    numbers.begin(),
    numbers.end(),
    bigNumbers.begin(),
    makeNumbersBig
  );

  // Print the values of bigNumbers
  for (const auto big : bigNumbers) {
    std::cout << big << std::endl;
  }
}
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C++ Generics / Templates

A while ago I discovered generics in Java. Today, I’m going to explore how to do the same with C++.

Generics in C++ are known as templates. We use the keyword template to tell the compiler that we are about to define one:

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template <typename T>
class Hello {};

In the example above, you can also see that typename is used to define the type. You might also see the keyword class used interchangeably (There are some scenarios where they are not interchangeable, but I’m not going to cover those in this article):

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template <class T>
class Hello {};
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