Sharp PC-1211/TRS-80 PC-1 program tapes from Radio Shack

[Dave Britten]

Yes, I believe you are correct that there's an error in the original programs. The PC-1211 and PC-1250/1251 both require LET when making a variable assignment immediately following IF. The THEN keyword is only used as a synonym for GOTO following an IF. All of the Sharp pocket computers I've used have these same syntax rules.

Some examples:

IF X>1 THEN 200
IF X>1 GOTO 200
IF X>1 LET X=X-1
IF X>1 PRINT "X>1"

I'm surprised that IF M>=360M=M-360 doesn't throw a syntax error since there's no subordinate statement following the IF. I'm assuming the condition ends up being evaluated as something like IF (M>=(360M))=(M-360).

Interestingly, several of the manuals contained either a printed addendum/errata, or hand-written notes and corrections from the previous owner, but the surveying manual appears to lack either.