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crez

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Joined: 24/10/2012
Location: Australia
Posts: 152

Posted: 08:49pm 04 Jun 2021

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Open "doc.txt" For input As #1
Line Input #1,t$
For i= 1 To 10
Print Asc(Mid$(t,i,1)),
Next i
Close #1

Open "doc.txt" For input As #1
t=Input$(10,#1)
For i= 1 To 10
Print Asc(Mid$(t,i,1)),
Next i
Close #1
End

gives
> RUN
97 32 98 32 99 32 100 32 101 32
97 9 98 9 99 9 100 9 101 9
>

line input returns spaces = chr$(32)
input$ returns tabs = chr$(9) which is what is in doc.txt

Why?

Geoffg

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Joined: 06/06/2011
Location: Australia
Posts: 3292

Posted: 03:24am 05 Jun 2021

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LINE INPUT uses the same mechanism for getting a line as does the console and loading a program from an SD card. This includes turning tabs into spaces, setting bit 8 to zero, removing control chars and handling the variations in terminating the line (ie, CR, LF, CR/LF, etc).

This was implemented many years ago and, from memory, it matches the way traditional BASICs worked (primarily Microsoft BASIC). As you pointed out INPUT$() is the way to go if you want every byte without translation.

Geoff

Geoff Graham - http://geoffg.net

crez

Senior Member

Joined: 24/10/2012
Location: Australia
Posts: 152

Posted: 03:41am 05 Jun 2021

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Thanks Geoff,
I was tidying up a bit of code I wrote a while back that reads tab delimited fields. I couldn't remember why I hadn't used 'line input', but I do now.

David

phil99

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Joined: 11/02/2018
Location: Australia
Posts: 2640

Posted: 04:12am 05 Jun 2021

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Same effect in a different setting - send an email containing a table with neat columns of data and it arrives messed up. Tabs turn into to spaces.

thwill

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

Posted: 06:13am 05 Jun 2021

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Geoffg said ... handling the variations in terminating the line (ie, CR, LF, CR/LF, etc).

Are you sure it handles CR without LF, i.e. Classic Mac style? I'm sure Turbo64 and I encountered one of those abominations recently and I had to write my own Line Input replacement. This was on the CMM2.

Best wishes,

Tom

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

Geoffg

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Joined: 06/06/2011
Location: Australia
Posts: 3292

Posted: 08:49am 05 Jun 2021

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When using INPUT or LINE INPUT MMBasic for the Micromite will work correctly with lines terminated by a CR/LF pair or a single LF. This will not affect files written by MMBasic (which normally use CR/LF) but files written with strange combinations such as a single CR or LF/CR should use INPUT$() instead. The console input will translate CR into a newline so pressing Enter on a keyboard will not cause problems.

I'm not sure if this has carried into the CMM2 but I would guess that it has as it is in the core of MMBasic.

I had a lot of trouble with detecting end of line (damn DOS and the rest of the world, why could you not be like UNIX?). After a lot of attempts the above was the best that I could come up with.

Geoff

Geoff Graham - http://geoffg.net

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