Way back in the day on of my favourite programming tools was Nibble BASIC from the Nibble Magazine. It allowed you to write Applesoft programs without line numbers, and added additional commands such as If/ElseIf/Else, and Loop/EndLoop, as well as Goto and Gosub labels rather than using line numbers. I added extra commands such as Repeat/Until and While/EndWhile, and “Turtle” like graphic commands. In a previous RetroChallenge I was going to re-write Nibble BASIC in itself, but my project this time is to write an external “compiler” to take an enhanced Applesoft like script and convert it to run on an Apple][. My target script is a version of the traditional “Hello World” program below: # RetroChallenge 2016/10 # Hello World Program my String$ = “Hello World” my Counter% = 10 my Count% = 1 my Co% = 2 my Characters_Per_Line = 40 home for i = 1 to Counter% Co% = centre_text(Characters_Per_line,String$) next Print “String$ [“;String$;”]” PRINT “Counter%>”;Counter% ? “Count% >”;Count% print “Co% >”;Co% sub centre_text my line_size = shift my text$ = shift my start_character = int(len(text$)/2)) htab start_character : print text$ return(start_character) So, in a nutshell, declared variables with full name support, not just up to the first two characters, called subroutines passing and returning values (no recursion support) , and case insensitive commands. If time permits, I’ll add additional Applesoft commands to the parser.
September 21st, 2016No Comments, Apple2, Programming, RetroChallange, by Michael.
January 9th, 2014No Comments, Apple2, Programming, RetroChallange, by Michael.
Thought I’d get a jump on the rewriting of S-Basic in S-Basic by dumping the S-Basic Applesoft code to a text file, then reformatting it as S-Basic, then running it through S-Basic5.3 on my disk image. Great idea, but . . . . . The code is just too unstructured. Too many unexpected terminations within a routine using a GOTO that drops you part way into another routine. Arrrrrrrrgh! I love structure, indenting, flow control, so looks like I’ve got to do it myself then. So back to my original plan of writing from scratch using the Applesoft listing as a guide only.
January 3rd, 2014No Comments, Apple2, Programming, RetroChallange, by Michael.
OK, so it’s summer here in Australia, so what is this “Winter Warmup” thing. 2014WW is the Retrochallenge and to quote the site: “In a nutshell, the RetroChallenge is a loosely disorganised gathering of RetroComputing enthusiasts who collectively do stuff with old computers for a month. The event is very much open to interpretation… individuals set there own challenges, which can range from programming to multimedia work; hardware restoration to exploring legacy networking… or just plain dicking around. It really doesn’t matter what you do, just so long as you do it. While the RetroChallenge has its competitive side, it’s not really a contest… it’s more like global thermonuclear war — everyone can play, but nobody really wins.”