To recap, to write suru I had to: Write a parser in a Parser Expression Grammer to parse taskfiles. Generate a build graph listing the dependency roots and their dependents. Execute the build graph in a multithreaded manner. All in all, writing Suru only took 4 days of work, and only a couple hundred of lines of code. I enjoyed how Rust combines bits of C++ and Haskell into a cohesive language that offers the elegance of Haskell and the versatility of C++....
The second part of building Suru is constructing a build graph. A build graph is almost certainly necessary in the context of multithreading because of the presence of diamond dependencies. Constructing a graph in Rust isn’t too bad, but does require a little big of fandangling. Rc, Arc, Refcell, Mutex, RwLock??? I’ve seen some people get confused between the various constructs Rust has surrounding multithreading, but if you have a context in C++ multithreading it’s not very complicated....
The first part of building suru was creating a parser, which was the part with the most false starts. The syntax I had in mind was relatively poorly defined at the time. Unfortunately, this lead to me a parser only to find out that it wouldn’t inherently work. Nom I literally searched up parsers on lib.rs, and the first result I found was nom. Nom is a combinator parsing library intended for parsing binary formats, but also was serviceable for parsing text....
For a long time, I wanted to make a makefile replacement. Writing a good makefile is surprisingly non-trivial if you want certain features. For example, the internal pattern rules of make fail if you want to do an out of tree build, which is most modern builds. Moreover, making sure that make does not fail when a dependent header file is surprisingly obscure. Even to this day, the best makefile template is very much a matter of debate....