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what are these symbols in this VIC-20 MLX program?


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So before I go through typing in the lengthy Speedscript program, I first need to type in and save this MLX 1 page program. Before I attempt this though, I previewed it, luckily, and was a tad confused regarding lines 100-140, and especially lines 120 and 130. So before I actually just type, I would rather understand here:

 

1) In line 110 for example, are the commands within the {} like RVS and 14 SPACES to be typed verbatim in type like that, literally within the { } as {RVS}, or are they actually telling the programmer something, in the latter case to move the cursor 14 spaces?  (In my basic programming years, I never encountered anything like this in the programs I've ever typed in.)

 

2) As for lines 120 and 130, I have what I believe is one of the earlier models of the VIC, the exact one on the Wikipedia page. I see the key on the left side of the CLR HOME button, but I am confused with how they got it to print underlined like it shows, and the character to its left , the asterisk related one to appear, as well as the occasional underlines I see throughout the program in later program lines.

Some more curve balls in line 130 as well.

 

Anyone familiar with this hopefully can clarify for me. If you scan through this program, you'll see more of what I mean with the underlines. Thankfully, the program gets way more straightforward towards the middle and to the end.

 

Thank you

 

 

 

 

 

 

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Edited by newTIboyRob
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There's an article in the magazine called "Compute!'s guide to typing in programs" that will explain their listing conventions.

The short version is:

Things in {} represent control characters.  {RVS} means press Ctrl-9 (RVS ON). {OFF} means press Ctrl-0 (RVS OFF)

{14 SPACES} means push the space bar 14 times.

{CLR} means press Shift-CLR/HOME 

Except for spaces, these will be displayed in the actual listing on the screen as reverse graphical characters.  {RVS} will be a Reverse R, {CLR} will be a reverse heart symbol, etc.

 

Characters that are underlined mean you should type them while holding down SHIFT.  S means Shift-S, but will show a heart symbol.

Characters in [< >] brackets means you should hold down the Commodore key while typing them. [<S>] means Commodore-S, which will also appear as a graphical symobl.

 

 

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