Goodness in programming languages, part 2 " getting your code running

Posts in this series: Syntax, Deployment, Metaprogramming, Ownership

The fancy word for what I'm talking about here is Deployment. How easy is it, once you've written your code, to get it running on someone else's computer? What barriers are there to someone else using your program?

Examples of potential barriers include:

• Having to download some other program first, e.g. a runtime or some kind of dependency.
• The actual program being a huge download.
• Something mysteriously not working because of different versions of something on the person's computer.
• The program simply not working on the operating system or machine architecture of the computer.

Anything that can be done to remove these barriers makes my life as the supporter of the program easier, and makes it more likely people will use it.

Here are some things I like:

• Java's ability to run almost anywhere. Once you have the runtime, Java code is relatively easy to get running on many different operating systems and architectures, using almost-identical code. Other runtime-based languages are also strong here.
• Java and Python's large built-in libraries. Both Java and Python include large amounts of functionality in their standard libraries, reducing the need to depend on third-party components.
• Python and Perl's ability to work out of the box on most Linux systems. If you are developing for Linux, you can pretty much guarantee that an up-to-date runtime will be available, meaning no dependencies at all are needed.
• Many languages' easy integration with Linux packaging. Most of the above barriers disappear if you can install dependencies using your operating system's built-in package manager.
• Quickly's easy way to build your program into the packaging system. Things really become easy if your program itself is integrated into the packaging system.
• C and C++'s lack of dependencies. It is possible to write C and C++ programs that depend on nothing except standard runtime libraries, which are almost guaranteed to exist on most machines.

One way to handle dependencies is to package them together with your code. This is what most corporate Java software does - the specific Java runtime that is known to work is packaged with the program itself. This makes for big downloads, and defeats the concept of providing a single package for all platforms, but it does work. It also makes for huge headaches to do with licensing, and is often impossible for software producers who don't employ legions of lawyers. It also feels bad and wrong.

When packaging and deploying software, I subscribe to the philosophy of "Find the dependencies - and eliminate them". Until someone can click a single button and have your software running, you haven't finished.