This morning I received an email from my friend Mazlina, who I worked with in London, saying she had been trying to do just that and had coincidentally stumbled on my post*. However it hadn't worked out quite as easily for her as it had for me.
It turned out to be due to a Java version problem. While 1.8 was installed, brew --config claimed that only 1.6 was, which is insufficient for Trinity installation.
Here's how she solved it, quoting from her email:
"First, I did
and just cleared up whatever it told me to [...]
$ brew doctor
Your system is ready to brew.
brew cask search java
it lists down the available java versions (the one you have, 8, is just java), and I went with 9-beta because that was the only one I could download at that time. And when I ran
$ brew cask install java9-beta
$ brew install trinity
worked like a charm.
Not sure if that's exciting enough to go on the blog, but it solves it anyway."
(For reference, as I told her, given the average excitement level of the blog this should fit right in!)
* I'm never really sure whether these posts are read or not (as the stats from Blogger are always inflated by scanning bots) apart from when people let me know they've seen them - so if you ever bump in to me at a conference or something and have found one of them useful or interesting please let me know, I love to hear about it!