In software, a spike is some programming to investigate options or answer questions or to test design ideas. The term came from XP (extreme programming) and is used in agile and Scrum.
As a way to learn Go I've been investigating what it would be like to use it to implement Suneido. I've implemented various bits and pieces like lexical scanning, memory mapped file access, decimal floating point numbers, string concatenation, and hash tables.
In the Java implementation of Suneido I was able to leverage the Java virtual machine. In Go (as in the original C++ version of Suneido) I would need to write my own bytecode interpreter. To investigate this, I did an end to end spike from lexing to parsing to code generation to byte code interpreter. I even implemented a basic REPL (Read, Eval, Print Loop). All it currently handles are simple expressions like 100 + 50 - 25 or "hello" $ "world". But it's implemented with the right structure to flesh out into the full language. (The code is on Github if you're interested.)
I've written about 4000 lines of Go code so far. Not enough to be an expert by any means, but enough that I don't feel like a newbie anymore. It's been mostly low level code, I haven't done anything with goroutines and channels yet.
It's been remarkably painless. I think it helps to have a C/C++ background. Of all the languages I've dabbled in in recent years, Go has been the easiest to pick up and be productive in. That's partly due to the small, simple language, and partly due to the good default tools. The Java language wasn't hard to pick up, but the libraries and tools are definitely more complex.
The fast compiles are a key feature. After working in Java I think it would be hard to give this up. Considering the classic compile and link approach, running Go code seems just as fast as running Java code.
I almost find Go's simplicity a little disappointing. I love reading about complex languages like C++ and Scala and all the wild and wonderful things you can do with them. What software geek wouldn't love turing complete templates and type systems! Go doesn't have those kinds of things, and therefore doesn't have intricate books about them.
But as far as something I actually want to use, and not just read about - in that respect Go is great.