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Volhout
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Posted: 10:13am 04 Oct 2024

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For most of you this will be simple, but I have not found a solution yet.

In a basic program you can

a$="hello"

But if you want to execute this from a script file you have to

EXECUTE " a$="hello" "

But how to get the double quotes around the "hello". I tried ""hello"" and \"hello\"
and chr$(34)hellochr$(34)...

Just have not found it yet...

anyone ?

Volhout

PicomiteVGA PETSCII ROBOTS

Martin H.

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Posted: 10:18am 04 Oct 2024

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? CHR$(34);"HELLO";CHR$(34)

a$=CHR$(34)+"HELLO"+CHR$(34)

with EXECUTE I get an Error: Unknown command
Edited 2024-10-04 20:25 by Martin H.

'no comment

matherp
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Posted: 10:23am 04 Oct 2024

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a$=chr$(34)+hello+chr$(34)

or

PicoMite Manual page 27

OPTION ESCAPE
a$="\qhello\q"
a$="\031hello\031"

thwill

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Posted: 10:44am 04 Oct 2024

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matherp said

OPTION ESCAPE
a$="\qhello\q"
a$="\031hello\031"

Presumably you mean:

a$="\034hello\034"

But IMO that's a snafu as (by C convention) that should be the syntax for an octal sequence, not a decimal sequence.

If you aren't on the PicoMite then these might be of use:

' Decodes a string containing "C" escape codes.
'
' Note: does not handle octal escape codes.
'
' state%:
' 0 = base state
' 1 = looking for escape code
' 2 = expecting 1st hex digit
' 3 = expecting 2nd hex digit
Function str.decode$(s$)
Local ad%, ch%, prev%, state%, t$

For ad% = Peek(VarAddr s$) + 1 TO Peek(VarAddr s$) + Len(s$)
ch% = Peek(Byte ad%)
Select Case ch%
Case &h5C ' \
state% = 1
Case Else
Select Case state%
Case 0
Cat t$, Chr$(ch%)
Case 1
Select Case ch%
Case &h22 : ch% = &h22 ' \"
Case &h27 : ch% = &h27 ' \'
Case &h30 : ch% = &h00 ' \0
Case &h3F : ch% = &h3F ' \?
Case &h5C : ch% = &h5C ' \
Case &h61 : ch% = &h07 ' \a
Case &h62 : ch% = &h08 ' \b
Case &h65 : ch% = &h1B ' \e
Case &h66 : ch% = &h0C ' \f
Case &h6E : ch% = &h0A ' \n
Case &h71 : ch% = &h22 ' \q
Case &h72 : ch% = &h0D ' \r
Case &h74 : ch% = &h09 ' \t
Case &h76 : ch% = &h0B ' \v
Case &h78 : state% = 2 ' \x
Case Else : Cat t$, "\"
End Select
If state% = 1 Then
Cat t$, Chr$(ch%)
state% = 0
EndIf
Case 2
Select Case ch%
Case &h30 To &h39, &h41 To &h46, &h61 To &h66 ' 0-9, A-F, a-f
prev% = ch%
state% = 3
Case Else
Cat t$, "\x" + Chr$(ch%)
state% = 0
End Select
Case 3
Select Case ch%
Case &h30 To &h39, &h41 To &h46, &h61 To &h66 ' 0-9, A-F, a-f
Cat t$, Chr$(Val("&h" + Chr$(prev%) + Chr$(ch%)))
Case Else
Cat t$, "\x" + Chr$(prev%) + Chr$(ch%)
End Select
state% = 0
End Select
End Select
Next

Select Case state%
Case 1 : Cat t$, "\"
Case 2 : Cat t$, "\x"
Case 3 : Cat t$, "\x" + Chr$(prev%)
End Select

str.decode$ = t$
End Function

' Encodes a string using "C" escape codes.
Function str.encode$(s$)
Local ad%, ch%, t$
For ad% = Peek(VarAddr s$) + 1 TO Peek(VarAddr s$) + Len(s$)
ch% = Peek(Byte ad%)
Select Case ch%
Case &h00 : Cat t$, "\0"
Case &h07 : Cat t$, "\a"
Case &h08 : Cat t$, "\b"
Case &h09 : Cat t$, "\t"
Case &h0A : Cat t$, "\n"
Case &h0B : Cat t$, "\v"
Case &h0C : Cat t$, "\f"
Case &h0D : Cat t$, "\r"
Case &h1B : Cat t$, "\e"
Case &h22 : Cat t$, "\q"
Case &h27 : Cat t$, "\'"
Case &h3F : Cat t$, "\?"
Case &h5C : Cat t$, "\\"
Case < &h20, >= &h7F : Cat t$, "\x" + Hex$(ch%, 2)
Case Else : Cat t$, Chr$(ch%)
End Select
Next
str.encode$ = t$
End Function

allowing you to write either:

a$=str.decode$("\qhello\q")

or:

a$=str.decode$("\x22hello\x22")

Best wishes,

Tom
Edited 2024-10-04 20:52 by thwill

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matherp
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Posted: 11:01am 04 Oct 2024

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Nobody uses octal anymore so I re-purposed that syntax - yes it should be \034

From the manual

Quote \nnn any The byte whose value is given by nnn interpreted as a decimal number
\&hh any The byte whose value is given by hh… interpreted as a hexadecimal number

thwill

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Posts: 4036

Posted: 11:07am 04 Oct 2024

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matherp said Nobody uses octal anymore so I re-purposed that syntax - yes it should be \034

Whilst I personally stay clear of octal I still think it dangerous to subvert convention in an engineering context such as a programming language.

YMMV,

Tom

Game*Mite, CMM2 Welcome Tape, Creaky old text adventures

Volhout
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Posts: 4222

Posted: 11:11am 04 Oct 2024

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Thank you for your help.

Volhout

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thwill

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Posted: 11:25am 04 Oct 2024

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thwill said ... I still think it dangerous to subvert convention in an engineering context such as a programming language.

... though I now observe you are not the only one to have done it

: https://freebasic.net/wiki/TblEscapeSequences

I'll get back in my box,

Tom

Game*Mite, CMM2 Welcome Tape, Creaky old text adventures

disco4now

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Posts: 896

Posted: 11:29am 04 Oct 2024

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The EXECUTE command expects a string.
Use chr$(34) to put the extra quotes.(or OPTION ESCAPE with \q )
pass to EXECUTE as below.

execute "a$="+chr$(34)+"hello world"+chr$(34)

> ? a$
hello world

Latest F4 Latest H7

Volhout
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Location: Netherlands
Posts: 4222

Posted: 11:38am 04 Oct 2024

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Thank you for your help.

I looked at your proposals and I feel so stupid.

I wanto to add test to a log (in this case a text array called r$() and use pointer i. This routine will later change into writing to a file in the filesystem.

sub add_log(a$)
r$(i)=a$
inc i,1
end sub

I run a script file, and when it it should store text in the log file this is the current code (I want to execute txt$).

read command$
select case command$
case "EXE"
read p:read txt$
execute txt$+chr$(13)

The txt$ is read from DATA statements

data "EXE",0,"add_log(str$(a)+chr$(32)+chr$(109)+chr$(87))"

and above works. It adds the value of a (i.e. 100), and then the text " mW".
i.e. "100 mW" to r$(i)

I try to use the escape codes, so I won't have to translate every ASCII character manually. So I try...

data "EXE",0,"add_log(str$(a)+\q mW\q)"
data "EXE",0,"add_log(str$(a)+"\q mW\q")"
data "EXE",0,"add_log(str$(a)\q mW\q)"
data "EXE",0,"add_log(str$(a)"\q mW\q")"

O coarse I also tried \034.

B.T.W. MMB4L does error on OPTION ESCAPE

Volhout
Edited 2024-10-04 21:40 by Volhout

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thwill

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Posted: 11:49am 04 Oct 2024

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Volhout said B.T.W. MMB4L does error on OPTION ESCAPE

Yes, sorry @Volhout, I don't think I'll ever implement OPTION ESCAPE* in MMB4L, though I have been considering:

a$ = c"String using C escape sequences"
a$ = !"String using FreeBASIC escape sequences"

or something similar.

In the meantime str.encode$() and str.decode$() are your friend

.

* At the risk of controversy I think it's a broken design. One issue (in addition to being different from C escapes) is that because it's not on a per-string basis Peter had to "hack" around any place where a string was being used as a file path (which frequently contain the \ character but don't mean it to introduce an escape).

YMMV,

Tom
Edited 2024-10-04 21:50 by thwill

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Mixtel90

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Posted: 12:56pm 04 Oct 2024

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I've seen BASIC implementations that allow both single and double quotes. You have to match the pairs though:

print "'this is a string'"
'this is a string'

print '"this is another"'
"this is another"

print "'a load of rubbish"'
'a load of rubbish
(and probably an error message)

Neat, but probably non-standard.

Mick

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JohnS
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Posted: 01:53pm 04 Oct 2024

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Mick,

... and then can't have comments starting with a single quote (I guess).

John

JohnS
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Posted: 01:55pm 04 Oct 2024

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Volhout said

read command$
select case command$
case "EXE"
read p:read txt$
execute txt$+chr$(13)

The txt$ is read from DATA statements

I suspect the chr$(13) is not needed.

John

Mixtel90

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Posted: 03:41pm 04 Oct 2024

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Good point, John. I can't honestly remember.

Mick

Zilog Inside! nascom.info for Nascom & Gemini
Preliminary MMBasic docs & my PCB designs

toml_12953
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Posted: 07:47pm 04 Oct 2024

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disco4now said The EXECUTE command expects a string.
Use chr$(34) to put the extra quotes.(or OPTION ESCAPE with \q )
pass to EXECUTE as below.

execute "a$="+chr$(34)+"hello world"+chr$(34)

> ? a$
hello world

In some BASICs (such as ANSI) you can do this:

a$="She said, ""I see the tower!"""

using two quotation marks to mean one.

In some you can use either the apostrophe or quotation mark like this:

a$='She said, "I can see the tower!"'
b$="This is Sam's coat"

whichever mark is needed inside, the opposite one is used to enclose the entire string.

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