The Polyglot

Why more than one?

• Each computer language has different strengths and weaknesses
• Computer languages are designed for specific or general tasks
• The hardest language to learn is the first one

How to choose

• Simplicity/Familiarity
• Suitability for the task at hand:
  • Task
  • Performance
  • Platform
  • Distribution
• Maintanability/Code longevity

Hammer or screwdriver

Considerations

• Interpreted or compiled
• General purpose or domain specific
• Procedural, functional or declarative

Interpreted or compiled

• Compiled languages tend to run faster
• But the development cycle is typically slower
• A good combination is to prototype in an interpreted language, and if needed then port to compiled for speed
• Many interpreted languages offer "tricks" to achieve performance close to compiled languages, but this often requires specialized knowledge.
• But writing performante compiled code is hard
• i.e. writing performant programs is hard!

General purpose or domain specific

• Domain specific languages can simplify the learning curve and make code shorter and more manageable as they provide common functionality and abstractions
• But they can be harder to deploy on other people's systems
• And they do some things very well, but others badly or at all.

Procedural/Imperative languages

• The programmer must clearly describe the procedure and order in which things are to be done
• This often obscures the actual goal of the code for others reading it.

#include <stdio.h>

int main()
{
    int a = 3;
    int b = 2;
    
    int c = a + b;
    
    printf("%i", c);
    
    return 1;
}

C

Functional languages

• All code is function calls
• Often, there is no persistent state

(println (+ 3 4))

Clojure

Declarative languages

• Describe the what, not the how
• Useful when building static systems (the system is static but it can respond to interactive events)

Rectangle {
    width: 30
    height: width
    color: #ff0000
    
    Circle {
        width: parent.width /2
        height: width
        color: #00ff00
    }
}

QML