Day 265, Docent, Lisp

Saturday, 8/24/2019

I was chillin’ and killin’ time before my 11am departure for the museum when I remembered, oh, I should check the plants, maybe they need water. Stepped out on the deck and discovered that the plant stand holding the hanging pot for one of the wax plants had at some time fallen over, the pot shattered, and the plant, now a naked root ball, was looking water-stressed, not surprisingly.

Fortunately I had a spare pot and a bag of soil, so in a rather frantic ten minutes I got the plant re-established in a pot with dirt and water. All this while successfully keeping my white slacks clean. (This morning I noticed the plant was looking ok, and also that both the wax plants were putting out buds, they’re going to bloom again. They already bloomed prolifically back in — May? I remember they had just finished blooming before I moved to Channing House in June.)

Anyway I arrived at the Museum in plenty of time for my docent tour. I had a good sized group, 25 or so at the start, at least 15 still with me at the end.

There was an annoyance: I don’t recall if I mentioned about this dude who runs private tours. He’s big, looks Irish (sparse reddish hair, florid complexion), and appears to do a decent job of guiding small parties of 2-4 people through the museum. Unfortunately he seems to always be starting his tours just before 12 when I start my Saturday tour. So I catch up with him, lead my group through his, then he catches up and is there talking to his group on the fringes of my group. Today I twice turned up my little amp and deliberately talked over him. I’ve previously complained to Jesse, the floor manager, who said he would speak to the guy. We have no problem with people leading private tours. But it’s no bleepin’ secret that the official tours start at 12 and 2. If he’d just schedule for half an hour before or after, there’d be no problem. I sent an email to Jesse complaining. We’ll see.

Back home I spent some time with Lisp. I have finally found a decent tutorial book! It is Common Lisp: A gentle introduction to symbolic computation by David Touretzky. I’m using the free online version; an updated version is available on Amazon. This guy knows how to introduce a complex subject! He takes it from the most basic fundamentals and builds concepts step by logical step, at every step showing the why of each idea, not just the what. It’s a model of good pedagogy, and I say that as a professional writer of manuals.

Part of the fun of Lisp is seeing the ancient roots of the language. It was first implemented on an IBM 704, a vacuum-tube computer, and features of that first implementation are still fundamental to the semantics of the language. Touretzky makes that clear, where none of the other tutorials I’ve seen did. None of the others made the very important connection between the way lists are laid out in memory and the way the language primitives work, and so forth.

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