encoding and decoding multilevel arrays

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danielrr
Posts: 117
Joined: Mon Mar 04, 2013 4:03 pm

encoding and decoding multilevel arrays

Post by danielrr » Wed Oct 30, 2019 12:17 pm

Hi all

I seem to be unable to arrayDecode an array containing more than two "levels"

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   put "one" into arrayBibliografia[1]
   put "foo" into arrayBibliografia[1]["one"]
   put "two" into arrayBibliografia[2]
   put "three" into arrayBibliografia[3]
   put "binfile:test" into nfile 
   open file nfile for write 
   get the result 
   if the result <> "" then errorFin "error al crear un archivo " & it. --it's ok up to this point, Daniel
   write arrayEncode(arrayBibliografia,"7.1") to file nfile
   close file nfile
   get the result
   if the result <> "" then errorFin "error al crear un archivo " & it
 open file nfile
   read from file nfile until eof
   close file nfile
   put arrayDecode(it) into arrayResult

At the end of this code, the output is puzzling. The contents of "one" in arrayResult is not "foo". Instead, contents of "1" and "3" are empty and content of "2" is "1869505798" ( :shock: )

The problem is worst if the array contains unicode chars. In that case the result can be erratic (as in the example above) of the arrayDecode function may not work at all

[-hh]
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Re: encoding and decoding multilevel arrays

Post by [-hh] » Wed Oct 30, 2019 1:25 pm

shiftLock happens

danielrr
Posts: 117
Joined: Mon Mar 04, 2013 4:03 pm

Re: encoding and decoding multilevel arrays

Post by danielrr » Wed Oct 30, 2019 2:59 pm

Thanks. Does it mean that there's no solution to the problem but to convert the array into a variable using a repertoire of delimiters before saving it to a file, and then turn again the variable into an array using the same repertoire of delimiters?

[-hh]
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Re: encoding and decoding multilevel arrays

Post by [-hh] » Wed Oct 30, 2019 3:35 pm

With a second read I noticed that you only wish to decode/encode the array, not flatten it, sorry.
Your problem may be the incomplete binary write/read. So you could try, which is moreover 'simpler':

write:

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put arrayEncode(arrayBibliografia,"7.1") into url ("binfile:"&stackFolder()&"test.data")
read:

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put arrayDecode(url ("binfile:"&stackFolder()&"test.data")) into dd
This works here (e.g. dd[1]["one"] is "foo").

__________________________________
I used also

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function stackFolder
   put the effective filename of this stack into f
   set itemdelimiter to slash; put empty into last item of f
   return f
end stackFolder
shiftLock happens

FourthWorld
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Re: encoding and decoding multilevel arrays

Post by FourthWorld » Wed Oct 30, 2019 4:05 pm

The output of arrayEncode is binary. The key to reading/writing those files is to use binary mode, e.g.:

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open file "whatever.lson" for binary write
...or the "binfile" option for the "put URL..." syntax as hh showed.

LSON files (LiveCode encoded arrays) are wonderfully robust and efficient, a good choice for many storage needs.
Richard Gaskin
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LiveCode development, training, and consulting services: Fourth World Systems: http://FourthWorld.com
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danielrr
Posts: 117
Joined: Mon Mar 04, 2013 4:03 pm

Re: encoding and decoding multilevel arrays

Post by danielrr » Wed Oct 30, 2019 5:04 pm

Works flawlessly, even with Unicode strings, thanks -hh, FourthWorld :D

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