The Wikimedia-OpenRefine group of prospective trainers (train-the-trainer program) is looking for someone who can teach the group one interactive session of approx. 1 to 1.5 hours, about the principles behind GREL. What are the typical ingredients/elements of the language, how to put these together, peculiarities to take into account... so a bit more of a 'programming' lesson rather than focus on recipes, etc.
There's a budget to pay for your time. The group has dedicated meeting times twice per month and it would be great if you can join one of its existing sessions (either on Wednesday evenings or Friday mornings UTC).
The group already knows how to look up expressions online, how to modify examples they find, and they are already collecting recipes that are helpful to the target audiences that they'll teach. What the group is looking for in a GREL session is: a deeper understanding of all the elements in the language, why expressions are built as they are, so that they understand it more deeply, become proficient in building expressions from scratch, and become more confident in teaching it to others.
I've asked several people already, and everyone I asked so far suggested they'd train this group in Jython/Python or JavaScript instead. I appreciate that offer, but we are really looking for GREL, as that is the language that OpenRefine 'ships with' and that prospective users/trainees generally expect trainers to be proficient in / be taught in.
Pinging @Martin - would appreciate passing on this message to the trainers you have been interviewing. Thank you!