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Forum Index : Microcontroller and PC projects : CMM2: Line continuation character, SWAP

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bar1010
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Joined: 10/08/2020
Location: United States
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Posted: 07:14pm 07 Jun 2021

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FreeBASIC uses the underscore character for line continuation.
Do we have something similar to use in the editor?
If not, could we have this functionality added?

Also I have seen a SWAP command in QuickBASIC which swaps the values of two variables.
Could we have this functionality added?

thwill

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Joined: 16/09/2019
Location: United Kingdom
Posts: 4311

Posted: 07:30pm 07 Jun 2021

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I will save Peter some time:

Line continuation: see http://www.thebackshed.com/Forum/ViewTopic.php?TID=12819

SWAP: probably not as the 128 tokens available for MMBasic commands has been reached on the CMM2 - it's an architectural limitation.

Best wishes,

Tom
Edited 2021-06-08 05:31 by thwill

MMBasic for Linux, Game*Mite, CMM2 Welcome Tape, Creaky old text adventures

thwill

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Posted: 07:34pm 07 Jun 2021

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Note that because parameters are pass by reference you could write SUBroutines to provide your own SWAP, you'd need one per type and unfortunately you'd have to pay a significant performance penalty over an inbuilt command.

Best wishes,

Tom

MMBasic for Linux, Game*Mite, CMM2 Welcome Tape, Creaky old text adventures

twofingers

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Joined: 02/06/2014
Location: Germany
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Posted: 07:36pm 07 Jun 2021

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thwill said SWAP: probably not as the 128 tokens available for MMBasic commands has been reached on the CMM2 - it's an architectural limitation.

I think, that is correct.

But it's easy to make your own:

For example, you might define a subroutine to swap two values, as follows:
SUB Swap a, b
LOCAL t
t = a
a = b
b = t
END SUB

(CMM2 manual p27)

... or write a short CSUB

Regards
Michael

causality ≠ correlation ≠ coincidence

CaptainBoing

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Joined: 07/09/2016
Location: United Kingdom
Posts: 2170

Posted: 08:23pm 07 Jun 2021

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it is likely you will only ever use SWAP in one or two places in any given program.

The overhead of a SUB makes for a very slow SWAP. If you are doing it in tight loops (e.g. in a sort function), better to do it inline for big increase in speed.

All things speed-wise are relative of course

LeoNicolas

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Joined: 07/10/2020
Location: Canada
Posts: 504

Posted: 10:59pm 07 Jun 2021

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There is a nice old challenge with the swap function. How can we do it without creating a third variable?

Edited 2021-06-08 09:19 by LeoNicolas

JohnS
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Joined: 18/11/2011
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Posted: 06:06am 08 Jun 2021

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Does it work with floating point, not to mention strings...

LOL

John

Mixtel90

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Joined: 05/10/2019
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Posted: 06:40am 08 Jun 2021

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Now there's a thought ...
Swap the variable pointers, not the variables.
Edited 2021-06-08 16:40 by Mixtel90

Mick

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Preliminary MMBasic docs & my PCB designs

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