The Universal Programming Language

Recently I tried to answer a question that I think is common to consider when you’re first learning about computer programming. I’ll paraphrase:

Why can’t there be an “universal” programming language that serves all purposes?

The number of programming languages in the world is dizzying. Names like JavaScript, Ruby, and C are known by programmers and non-programmers alike. Since technology constantly evolves, and learning many things takes more time than learning one thing, wouldn’t a reasonable expectation be that we’ll all someday coalesce around an ideal language, that’s perfect for every situation?

I think this is a fascinating idea. I’ll take my best shot at answering it here.

There can’t be a universal programming language because language design, like all design, always requires tradeoffs.

Let’s take two implementations of a ‘Hello World’ program. The first is written in C:

#include <stdlib.h>
#include <stdio.h>

int main(void)
{
  printf("Hello world!\n");
  return EXIT_SUCCESS;
}

The second is Ruby, a language written in C:

puts 'Hello world!'

What’s the difference? The Ruby code is one line, and the C code is eight lines. The C code begins with two lines that import the standard and IO libraries. Next we define our main function, call printf with a newline, and send an exit command.

But there’s another difference, too: the C code is orders of magnitude faster than the Ruby code. We know this without measuring, because C is always much faster than Ruby. It is optimized for speed.

The Ruby code is readable, enough that a non-programmer would probably have no trouble guessing what it does. That’s because Ruby is optimized for ‘developer happiness’, readability, and its ability to be non-surprising (known as the Principle of Least Surprise).

Code that’s fast has an important place. It gets the job done quickly and with fewer resources. In fields such as science these are are crucial attributes.

Code that’s readable is also important. It’s more friendly for beginners, and it’s arguably more productive for developers to work with.

As long as there’s a place for both of these goals, C and Ruby can coexist. You can’t get C’s performance in Ruby code, and you can’t get Ruby’s beautiful expressiveness in C code.

This logic applies to any programming language of significance. That is why there will probably never be a universal programming language.