Programming the TS1000 is like programming punch cards
Well, I have never programmed a punch card computer, but after several days of total frustration trying to enter, test and edit a BASIC program on the TS1000, I gave up. I haven't completely given up *BAM*, I am just writing it on my MacBook, in a text editor, and then entering it into the TS1000. This reminds me of how programmers used to have to write out their programs before trying to enter them on a punch card. The TS1000 is too slow to provide a good interface for stream of consciousness BASIC program editing. By the time I get a line entered, I forget what I was trying to do. I have spent many hours working on a simple program which I could have probably finished in just a few hours on an Apple II. I'm sure that machine language programs for the Z80 processor are really the TS1000's strong suit, but unfortunately, that's not what I'm working on.
Know your data types
I was running out of memory very quickly when setting up the game board for minesweeper. The board is represented by a 12x12 2-dimensional array of numbers with values 0 to 9. Little did I know that a number in Sinclair BASIC is represented by 5 bytes. As a result, I was using 720 bytes of memory, over a third of the memory of the TS1000, just to do some basic addition on the numbers. Instead I will use an array of strings. It too is a 2-dimensional array, but should only take up 144 bytes, plus some overhead. The result will be a slower program (to convert from character to number and back), but way less memory use.
Minesweeper has been done on the ZX81
Finding some existing minesweeper programs online for the ZX81 was a bit disappointing. However, I don't think either of them run in the standard 2k of memory for the TS1000 (although I haven't tried either of them). Even though I received my RAM chip for the upgrade, I really want to get this running in the standard configuration. So I'll keep working on this thing.