Friday, April 06, 2012

Playing with Go

With Go 1 being released, I’ve been playing with the language once again. As a long weekend hack, I created a clone of the literate programming Docco tool in Go – quite naturally called Gocco.

This blog post chronicles my feelings about the language, and some rough spots I got stuck in.

I started out with a direct translation of the original CoffeeScript to Go. Go is remarkably unlike C and more like high level languages. Much of the translation was automatic and is not very different from the CoffeeScript source, except the pervasive use of []byte rather than string.

What I loved about Go was the ability to directly import and install packages from various hosting services like GitHub, Google Code and Bitbucket. This combined with the go command makes package management a breeze. What I would really like though is for Go to switch to default local-to-global search path semantics, like npm. You can do it using GOPATH, but making it the default would be better. I am also not sure how you can specify which version of your dependencies to install.

The inbuilt templating support is also a great tool, I didn’t have to hunt around for a templating library, and the syntax was very clean and similar to Jinja2 or Mustache. There seems to be some bug in the ParseFiles method though, as it kept complaining that the template was incomplete or empty, but when I manually read the same file into a string and called Parse, it worked.

The tooling support is excellent, with gofmt and go ensuring everything is ‘standardised’ and makes others code much easier to read.

Coming to the slightly wonky/undefined/undocumented/(may actually be my fault) parts…

I still haven’t really figured out Go’s package system. The go/build package says it allows introspection over packages, like figuring out the installation path (Similar to Python’s __file__). But I couldn’t get this to work with my code, especially when it was not installed. I wanted it so I could keep the HTML template and CSS in separate files, and use the package path to figure out where they were kept. I finally got very frustrated and just stuck them into a go file as multi-line strings.

Syntactically, multiple return values are a good way to signal errors without exception handling, there really should be a way to ignore the second, error, parameter. Not being able to do that, makes composing functions impossible. Similarly the unused variables and imports errors can get annoying while developing, when there is lots of stub code. There is a workaround but still! :)

Still, it was a lot of fun using Go. I originally wanted to implement Docco in C, but the lacking standard library and types support was scaring me. Now I will reach for Go when it comes to systems programming.

A thanks to Russ Ross, for an excellent Markdown implementation.

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