Could someone please remind me how to use ] in Beebem?

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Commie_User
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Could someone please remind me how to use ] in Beebem?

Post by Commie_User » Thu Mar 15, 2018 8:23 pm

The Spacewar game demands it and I keep trying to remap keys and it just seems to map whatever it wants! (Typically the 3/4 symbol)

I think there should be two keyboard layouts in the options, 1 for literal BBC layout and 2 for how the PC keyboard actually is. Neither selection in BeebEm is an exact match and I can't seem to find anything where this was last mentioned in the search bar.

Thanks

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Pernod
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Re: Could someone please remind me how to use ] in Beebem?

Post by Pernod » Thu Mar 15, 2018 8:31 pm

Commie_User wrote:I think there should be two keyboard layouts in the options, 1 for literal BBC layout and 2 for how the PC keyboard actually is.
There are, go to Options -> Default Keyboard Mapping or Logical Keyboard Mapping.
- Nigel

BBC Model B, ATPL Sidewise, Acorn Speech, 2xWatford Floppy Drives, AMX Mouse, Viglen case, BeebZIF, etc.

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Re: Could someone please remind me how to use ] in Beebem?

Post by Commie_User » Thu Mar 15, 2018 8:56 pm

I did try those, hence that 'not an exact match' thing I was talking about.

I did press all the non-numeric and non-alphabetic keys in whatever mode - and got all but what I was after. I pressed them all with and without SHIFT.

The button to the left of 1 is always @.
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Pernod
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Re: Could someone please remind me how to use ] in Beebem?

Post by Pernod » Thu Mar 15, 2018 9:01 pm

The ] character does not exist in the teletext character set ie. MODE7. Change screen mode, ie. MODE6.
- Nigel

BBC Model B, ATPL Sidewise, Acorn Speech, 2xWatford Floppy Drives, AMX Mouse, Viglen case, BeebZIF, etc.

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Re: Could someone please remind me how to use ] in Beebem?

Post by Commie_User » Thu Mar 15, 2018 9:10 pm

OK, that works.

Thing is, it didn't seem to work in the game but it does now I've loaded it again! I reset to see what I was doing on the BASIC screen and I was clueless at that stage.

Thanks for that. It put me on to finding what's going right now. But I don't know what's happening on these computers, I really don't!

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Re: Could someone please remind me how to use ] in Beebem?

Post by crj » Fri Mar 16, 2018 4:36 am

Pernod wrote:The ] character does not exist in the teletext character set ie. MODE7. Change screen mode, ie. MODE6.
More exactly, ASCII character 93 does exist in any mode. In MODE7, it looks like "→". In other modes, it looks like "]" unless you've redefined it to look different.

Try this:

Code: Select all

MODE 6
10 PRINT "]"
LIST
RUN
MODE 7
LIST
RUN
...and you'll get a better feel for what's happening.

There are several characters which differ in appearance between MODE 7 and the default character set: [ \ ] ^ _ { ¦ } ~ in other modes turn into ← ¹₂ → ↑ — ¹₄ ‖ ³₄ ÷ in teletext. (If you ever have a reason to read screen memory directly, you'll discover that £ and # are exchanged as well, but the operating system fixes that one up for you.)

Yes, typing all those bizarre characters into stardot was a challenge; why do you ask? (-8

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Re: Could someone please remind me how to use ] in Beebem?

Post by Commie_User » Fri Mar 16, 2018 1:18 pm

I wonder why the same ASCII value returns a different character across the modes. Or, for that matter, why Control or Tab were obvious keystroke choices for game programmers. (Some are Caps Lock as well, I think.)

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Re: Could someone please remind me how to use ] in Beebem?

Post by danielj » Fri Mar 16, 2018 2:09 pm

It's only the teletext mode that's funky, as the teletext character set isn't perfect ASCII (as they - the people who designed the teletext spec, not Acorn - swapped out some characters to give things like 1/4, 1/2, arrowthingy etc).

d.

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Re: Could someone please remind me how to use ] in Beebem?

Post by crj » Fri Mar 16, 2018 6:03 pm

Indeed. The teletext character set is outside Acorn's control, embedded deep inside the SAA5050, which in turn is basically the same chip you'd have found in a teletext television set of the era.

Acorn could have made the character set in other modes match MODE 7. But they chose not to, instead making it conform to ASCII with just three minor exceptions:
  • Acorn put £ in place of ASCII's ` (backtick, grave accent, opening quote)
  • Acorn put ’ (apostrophe, or closing quote) in place of ASCII's ' (symmetric apostrophe/quote)
  • Acorn put ¦ instead of ∣
Once I'd moved on to systems with real ASCII, in hindsight it felt weird to me that Acorn both eliminated the asymmetric opening quote and switched the symmetric quote to a closing quote. I guess they intended it to be used solely as an apostrophe, with " being used for quotation.

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