Playing with the Ninja build system

Whenever I learn a new programming language I end up writing some toy examples to try to get a feel for what the language is about. This leads to the need to build code using many different compilers with their own flags, quirks, etc. Up until today I had used SCons for my build setup. But honestly, it always seemed like overkill to me. Because I only had about 5 programs to build per language with at most two files used to produce the program, a full-blown build system was never really needed. Add to the fact that I am building for languages that no build system would have built-in support for, it led me to always have a wandering eye for another build system I could use.

This past week someone on Google+  shared a post comparing configure+make, cmake+make, and cmake+ninja. I had never heard of Ninja, so I decided to have a look. It turns out someone had written a build tool whose only explicit job was to take a DAG, figure out what needed to be built, and then execute the commands for the build. No crazy metadata checks like Make, or fanciful features, just bare-bones building. Ninja was actually designed to be a target for other higher-level build systems like cmake which can do the pre-computation of what the DAG should be, leaving it to Ninja to drive the needed compilation.

What attracted me to it was that it was fast and the syntax was simple. I have code examples for 16 languages, of which 10 have build rules (one happens to be Python 2.7 as I pre-compile the .pyo files). Turned out to be a pretty straight-forward process to take my custom SCons commands and just translate them to the subsequent shell commands that Ninja would execute for me. They are a tad verbose in order to make sure that the ninja -t clean command would clean up all intermediary files (I'm looking at you OCaml, Haskell, Java, and Scala). But as I said, I typically never have more than 5 programs to build per language, so it wasn't that much of a burden. And if I really cared I could have written a Python script to auto-generate the Ninja files for me, but I decided the effort of writing the code would be just as much as writing the build files by hand.

I realize I could have used Make, but I honestly am not enamoured with that tool; requiring tabs just rubs me the wrong way. Plus it's rather slow in the common case of only changing a file or two compared to a complete build from scratch.

Overall, for my weird case Ninja worked out. For something more complex, though, I will consider looking at cmake+ninja as a build solution.