I'm not sure. I did it because of Jenkins Pipeline DSL; I learned enough to write ~400 loc of a build script from scratch. I was able to de-sugar the DSL and wrap raw APIs with a DSL of my own design (I'd say that I "wrote a couple of helper functions", but the former sounds way cooler...). I did stumble upon some gotchas - the difference between `def` and simple assignment when the target changes, for example.
EDIT: I wonder, is that level of proficiency enough for you to at least drop the scare quotes around "learn"? I feel that putting the quotes there is rather impolite.
> did you skim some docs and just learn what Groovy should be?
As I elaborate on in the comment below, there are different levels of proficiency and I never claimed mastery - just a basic proficiency allowing me to read all of the language constructs and write, as mentioned, a simple script from scratch, with the help of the docs.
> And did you already know any Java beforehand?
Well, a bit, although I didn't work with it professionaly in the last decade. However, knowing Java wouldn't be enough to make learning Groovy that fast - I have another trump card up my sleeve when it comes to learning programming languages. You might be interested in a section of my blog here: https://klibert.pl/articles/programming_langs.html if you want to know what it is. To summarize: I simply did it more than 100 times already.
> the scare quotes around "learn"? I feel that putting the quotes there is rather impolite
When I say I've learned (or learnt) a programming language, I mean more than a 4-hour jump start to basic proficiency level. Perhaps I was letting off some steam over the wild claims many programmers make regarding their PL expertise.
Did you know that Jenkins Pipeline cripples Groovy so all its features aren't available, specifically the Collections-based methods that form the basis of many DSL's?
> Did you know that Jenkins Pipeline cripples Groovy
Yes. I've run into some limitations; first because of a Pipeline DSL, and when I ditched it in favor of normal scripting I ran into further problems, like Jenkins disallowing the use of isinstance (due to a global configuration of permissions, apparently - I don't have administrative rights there) and many other parts of the language. It was kind of a pain, actually, because I developed my script locally - mostly inside groovysh - where it all worked beautifully and it mysteriously stopped working once uploaded. A frustrating experience, to say the least.
> over the wild claims many programmers make regarding their PL expertise.
I believe I'm a bit of a special case[1] here, wouldn't you agree? Many of the languages on that list I only learned about, however, many of them I learned, having written several thousand (on the low end) of lines of code in them. It's got to be at least 30, I think? I'd need to count.
Anyway, I argue that such an accumulation causes a qualitative difference in how you learn new languages, allowing for rapid acquisition of further ones. It's like in role-playing games, if you buff your stats high enough you start getting all kinds of bonuses not available otherwise :)
[1] If I'm not and you know of someone with the same hobby, please let me know! I'd be thrilled to talk to such a person!
How well did you "learn" Apache Groovy? Just enough to change a small Gradle build file?
And did you already know any Java beforehand? If so, then there's a lot less Groovy that needs learning.
Did you write enough Groovy code to stumble across some of its many gotchas, or did you skim some docs and just learn what Groovy should be?