request feature OPTION STARTPOINT 2

[rikky]

so we have INSTRREV that searches for something backwards.

According to the documentation:

Returns the position where needle$ begins in haystack$, but start searching from the end of haystack$, optionally at position z also counting from the end. The result is counted from the beginning of haystack$. If not found then this function returns the value '0'.

See also OPTION STARTPOINT to return the result counted from the end of haystack$.

That's nice and even very logical.
Until you start to examine JSON strings.
For then you are no longer searching for a needle in a haystack, but for a needle in a whole bunch of haystacks stashed upon each other.

You first have to INSTR to whatever you know already.
Then INSTR '}' for the end if the group.
Then INSTREV to the beginning of the group.
And this group might be part of a bigger group, which is part of an even bigger group, and all these groups might contain subgroups.

So you are going forward, backward, forward, backward, backward, forward, forward and backward again.

And every time you change direction, you have to recalculate the STARTPOINT, for OPTION STARTPOINT does not change the direction of the startpoint [,z] in INSTRREV(haystack$, needle$ [,z])

To clearify a few INSTRREV examples in BaCon4Bash format:

echo 123456789012345678901234567890 | INSTRREV 567
25

echo 123456789012345678901234567890 | INSTRREV 567 7
15

echo 123456789012345678901234567890 | INSTRREV 567 17
5

export STARTPOINT=TRUE

echo 123456789012345678901234567890 | INSTRREV 567
6

echo 123456789012345678901234567890 | INSTRREV 567 7
16

echo 123456789012345678901234567890 | INSTRREV 567 17
26


Horrible, if the string becomes complex, and you need the result for the next INSTR, and the result from that INSTR back for your next INSTRREV.

Now a few examples from the BaCon4Bash script INSTREV, attached below:

echo 123456789012345678901234567890 | INSTREV 567
25

echo 123456789012345678901234567890 | INSTREV 567 24
15

echo 123456789012345678901234567890 | INSTREV 567 14
5

Much easier, I think.

The next script is INSTREV.bac without the double 'R' that I wanted to publish in BaCon4Bash, but the 
Code Projects chapter is currently occupied, so I do this here:

This thing is doing just what I want.
Never mind the whole bunch of functions and subs that are not used.
It's just the ever evolving template for BaCon4Bash.
So if you're interested, I suggest you start reading from the bottum up, and skip the sh*t.

 Rik

OPTION EXPLICIT TRUE

GLOBAL version$
version$ = "0.14"

SUB HELP
       
 PRINT
 PRINT basename$ & " [option] " & Q$ & "haystack$" & Q$ & " " & Q$ & "needle$" & Q$ & " [<startpos>]"
 PRINT
 PRINT "haystack$ can also be piped into this command."
 PRINT
 PRINT "alternative for INSTRREV."
 PRINT "INSTRREV needs a [startpos] counted from the end."
 PRINT
 PRINT "startpos is counted from the BEGINNING of the string."
 PRINT "the returned result is also counted from the BEGINNING of the string."
 PRINT
 PRINT "options :"
 PRINT " -v --version     print version."
 PRINT " -h --help        print help."
 PRINT
 PRINT "example:"
 PRINT "echo 123456789012345678901234567890 | INSTREV 567 20"
 PRINT
 
END SUB

OPTION UTF8 TRUE
OPTION ERROR FALSE
OPTION COLLAPSE TRUE
OPTION BASE 1

DECLARE argument$ ASSOC STRING
GLOBAL basename$ = BASENAME$(TOKEN$(ARGUMENT$,1))
GLOBAL verbose = 0
GLOBAL dryrun = 0
GLOBAL retval = 0
GLOBAL input$
GLOBAL var
GLOBAL Q$ = CHR$(34)  : ' quote
GLOBAL BS$ = CHR$(92) : ' backslash

CATCH ERROR help

SUB help(function_name$, filename$, lineno)
   EPRINT ERR$(ERROR), " in function ", function_name$, " in file '", filename$, "' at line ", lineno
   END 123
END SUB

FUNCTION GET_STDIN$()
 
 LOCAL string$ TYPE STRING
 LOCAL stndin
 
 WHILE TRUE
stndin = WAIT(STDIN_FILENO, 50)  
IF stndin = 0 THEN BREAK
string$ = string$ & CHR$(stndin)
 WEND
 
 IF string$ <> "" THEN string$ = RIP$(string$,-1)
 RETURN string$
 
END FUNCTION

SUB THE_COMPUTER_SAYS_NO(lineno)
 
 EPRINT basename$ & ": The computer says no, in line " & STR$(lineno)
 IF retval THEN END retval
 END 1

END SUB

FUNCTION CHAR$(string$,number)

 RETURN MID$(string$,number,1)

END FUNCTION

FUNCTION LASTCHAR$(string$)

 RETURN RIGHT$(string$,1)

END FUNCTION

SUB SELECT_ARGUMENT

 LOCAL i
 LOCAL option$
 LOCAL counter = 0
 
 FOR i = 2 TO AMOUNT(ARGUMENT$)
 
   option$ = FLATTEN$(TOKEN$(ARGUMENT$,i))
   
   SELECT option$
 
     CASE "-v";
     CASE "--version"
       PRINT basename$ & " version : " & version$
       END 0
       
     CASE "--help";
     CASE "-h"
       HELP
       END 0
 
     CASE "--verbose"
       INCR verbose
     
     CASE "--dryrun"
       dryrun = 1
       
     DEFAULT
       
       IF LEFT$(option$,1) = "-" THEN
         EPRINT "wrong option"
         THE_COMPUTER_SAYS_NO(LINENO)
       END IF
       
       INCR counter  
       argument$(STR$(counter)) = option$
       
   END SELECT
 
 NEXT i
 
END SUB

FUNCTION ISNUMBER(string$)

 'This function returns TRUE if the string$ has a numeric value.
 
 LOCAL char$
 LOCAL i
 
 string$ = CHOP$(string$)
 
 IF LEFT$(string$,1) = "+" OR LEFT$(string$,1) = "-" THEN
   string$ = RIP$(string$,1,1)
 END IF
 
 'we might have one point in it.
 IF INSTR(string$,".") THEN
   string$ = RIP$(string$,INSTR(string$,"."),1)
 ENDIF
 IF INSTR(string$,".") THEN RETURN 0
 
 IF LEN(string$) = 0 THEN RETURN 0
 
 FOR i = 1 TO LEN(string$)
   
   char$ = MID$(string$,i,1)
   
   IF VAL(char$) = 0 THEN
     IF char$ <> "0" THEN
       RETURN 0
     END IF
   END IF
       
 NEXT i

 RETURN 1    : 'VAL(string$) gives wrong value for zero.
 
END FUNCTION

FUNCTION ISHEX(string$)

' The value for x$ can lie between 0 and 0x10FFFF. (who cares, it's not this function's job.)
' 0x means hexadecimal
' returns 1 if TRUE

LOCAL i
LOCAL char$

IF LEFT$(string$,2) <> "0x" THEN RETURN 0

IF LEN(string$) = 2 THEN RETURN 0

FOR i = 3 TO LEN(string$)
  char$ = CHAR$(string$,i)
  IF NOT(ISTOKEN("0 1 2 3 4 5 6 7 8 9 A B C D E F a b c d e f",char$)) THEN RETURN 0
NEXT i

RETURN 1

END FUNCTION

SUB SHUFF_DOWN

 'shifts the argument array one down
 'argument$("1") now becomes empty
 
 LOCAL i
 
 FOR i = NRKEYS(argument$) TO 1 STEP -1
   argument$(STR$(i+1)) = argument$(STR$(i))
 NEXT i
 
 argument$("1") = ""
 
END SUB

SUB UNJSON$(string$)

 LOCAL counter
 LOCAL result$
 LOCAL i
 LOCAL char$

 FOR i = 1 TO LEN(string$)
   
   char$ = CHAR$(string$,i)
 
   IF counter < 0 THEN counter = 0
 
   IF char$ = "[" OR char$ = "{" THEN
     counter = counter+3
     PRINT NL$ & SPC$(counter);
     CONTINUE
   END IF  
   
   IF char$ = "]" OR char$ = "}" THEN
     counter = counter-3
     PRINT NL$ & SPC$(counter);
     CONTINUE
   END IF  
   
   IF char$ = "," THEN
     PRINT NL$ & SPC$(counter);
     CONTINUE
   END IF  
   
   PRINT char$;
   
 NEXT i
 
END SUB

FUNCTION PRINT_FORMAT$(digits)
 
 'GLOBAL zero_digits$ = "%.0f"
 'GLOBAL one_digit$ = "%.1f"
 'GLOBAL two_digits$ = "%.2f"
 
 LOCAL return$ = "%." & STR$(digits) & "f"
 
 RETURN return$
 
 'PRINT VAL("123") / VAL("8") FORMAT PRINT_FORMAT$(3)
 
END FUNCTION

FUNCTION INSTREV(VAR bla$ SIZE size)
 
 'alternative for INSTRREV.
 'INSTRREV needs a [startpos] counted from the end: BAH.
 'note: all arguments must be strings.
 'format: INSTREV(haystack$,needle$,[startpos])
 'startpos is counted from the BEGINNING of the string.
 'the returned result is also counted from the BEGINNING of the string.
 'OPTION BASE 1 is presumed.
 
 LOCAL startpos = 0
 LOCAL pos
 LOCAL haystack$
 LOCAL needle$
 LOCAL char$
 
 IF size < 2 THEN
   EPRINT "Wrong format for function INSTREV"
   THE_COMPUTER_SAYS_NO(LINENO)
 END IF  
 
 IF size > 3 THEN
   EPRINT "Wrong format for function INSTREV"
   THE_COMPUTER_SAYS_NO(LINENO)
 END IF
 
 IF size  = 3 THEN
   IF bla$[3] = "" THEN bla$[3] = STR$(LEN(bla$[1]))
   IF NOT(ISNUMBER(bla$[3])) THEN
     EPRINT "startpos is NOT a number in function INSTREV"
     THE_COMPUTER_SAYS_NO(LINENO)
   END IF
   IF INSTR(bla$[3],"+") OR INSTR(bla$[3],"-") OR INSTR(bla$[3],".") THEN
     EPRINT "startpos is NOT a number in function INSTREV"
     THE_COMPUTER_SAYS_NO(LINENO)
   END IF
 END IF
 
 haystack$ = bla$[1]
 needle$ = bla$[2]
 
 startpos = VAL(bla$[3])
 pos = LEN(haystack$)
 
 IF startpos < pos THEN pos = startpos
 
 IF haystack$ = "" OR needle$ = "" THEN
   'yes, this is possible.
   'INSTREV("","")
   RETURN 0
 END IF
 
 char$ = CHAR$(needle$,1)
 
 WHILE TRUE
   IF CHAR$(haystack$,pos) = char$ THEN
     IF MID$(haystack$,pos,LEN(needle$)) = needle$ THEN BREAK
   END IF
   IF pos = 0 THEN BREAK
   DECR pos
 WEND

 RETURN pos

END FUNCTION

SELECT_ARGUMENT

'this one AFTER figuring out the ARGUMENT$
'OPTION QUOTED FALSE

input$ = GET_STDIN$()

IF LEN(input$) != 0 THEN
 SHUFF_DOWN
 argument$("1") = RIP$(input$,-1)
END IF

PRINT INSTREV(argument$("1"),argument$("2"),argument$("3"))


[vovchik]

Dear Rik,

Couldn't you use INBETWEEN$ and OUTBETWEEN$ in that JSON processing? Just an idea...

With kind regards,
vovchik

[rikky]

I don't think so.

You have for example a Galaxy with planets:

{Galaxy:{"planet":{"a":{"humans":{"name":"John","adress":...

Now you want to know if there is an octopuss living on planet 'g' with the same name, and under which stone it lives.

Maybe this is possible with IN-OUTBETWEEN, but I don't see it.

Q$ = CHR$(34)
INBETWEEN$( "{" & Q$ & "g" & Q$ & ":{" , "}" )
Whether you take the greedy option or not, you have always the wrong "}"

 Rik.

[Pjot]

Hi rikky,

The INBETWEEN$ function does have an option for balancing. These examples show the difference:

PRINT INBETWEEN$("{ some { brackets } } { here }", "{", "}", 0)
PRINT INBETWEEN$("{ some { brackets } } { here }", "{", "}", 1)
PRINT INBETWEEN$("{ some { brackets } } { here }", "{", "}", 2)


This is the result:

some { brackets
some { brackets } } { here
some { brackets }


So as can be observed, the option '2' actually returns a balanced result.

HTH
Peter

PS I made a JSON parser once, it is based on recursion and returns a delimited string. You can find it here.

[rikky]

Ah ja, I knew this JSON program existed but could not find it anymore.
Thanks.

 Rik.

[rikky]

So after reading and studying this JSON thing, and making mistakes and trying again,
I have something different.

I'm NOT saying it is better. although I like it more because it's definitely more human readable.
And delimited, if you do NOT put OPTION COLLAPSE to TRUE

Why not a function?
Because you do not want to know how big certain JSON strings are, and how slow an RPi3 is. ;°)


 LOCAL counter
 LOCAL i
 LOCAL char$
 LOCAL toggle        : ' prevent double newline for '},'
 LOCAL toggle2 = 1   : ' first char, do not print newline
 LOCAL toggle3       : ' prevent printing space
 LOCAL toggle4       : ' Newline is just printed
 LOCAL quoted
 LOCAL backspace
 LOCAL tablen = 4
 
 FOR i = 1 TO LEN(string$)
   
   char$ = CHAR$(string$,i)
   
   IF toggle3 THEN
     IF char$ = " " OR char$ = "," THEN
       CONTINUE
     END IF
   END IF
   
   toggle3 = 0
     
   IF counter < 0 THEN counter = 0

   IF NOT(quoted) THEN
     IF char$ = NL$ OR char$ = " " THEN
       CONTINUE
     END IF
     IF char$ = "[" OR char$ = "{" THEN
       toggle3 = 1
       IF NOT(toggle2) THEN
         counter = counter + tablen
         PRINT NL$ & SPC$(counter);
         toggle = 0
         toggle2 = 0
         toggle4 = 1
         backspace = 0
         CONTINUE
       ELSE
         toggle = 0
         toggle2 = 0
         backspace = 0
         CONTINUE
       END IF  
     END IF
     
     toggle2 = 0
   
     IF char$ = "," THEN
       toggle3 = 1
       IF NOT(toggle) THEN
         PRINT NL$ & SPC$(counter);
         toggle4 = 1
         backspace = 0
         CONTINUE
       END IF
       toggle = 0
     END IF  
   
     IF char$ = "]" OR char$ = "}" THEN
       toggle3 = 1
       counter = counter - tablen
       PRINT NL$ & SPC$(counter);
       toggle4 = 1
       toggle = 1
       backspace = 0
       CONTINUE
     ELSE
       toggle = 0
     END IF  
     
     IF char$ = NL$ THEN
       backspace = 0
       CONTINUE
     END IF
     
   END IF
   
   toggle = 0
   toggle2 = 0
   
   IF char$ = Q$ THEN
     IF quoted THEN
       IF NOT(backspace) THEN
         quoted = 0
       END IF
     ELSE
       quoted = 1
     END IF
   END IF
   
   IF char$ = BS$ THEN
     IF quoted THEN
       IF backspace THEN
         backspace = 0  : ' \\
       ELSE
         backspace = 1
       END IF
     ELSE
       'should not happen
       backspace = 0
     END IF
   ELSE
     backspace = 0
   END IF
   
   PRINT char$;
   IF char$ <> " " THEN toggle4 = 0
 NEXT i
 
 'did we close?
 IF toggle4 THEN
   PRINT CR$;
 ELSE
   PRINT
 ENDIF
 
END SUB
By the way,
Now that there are RPi4's available, and even RPi400's.
I want to use this opportunity to call out to everybody who owns a Rpi_old:

DO NOT throw them away.

 Rik.

Edit:  CHAR$(string$,i) is unfortunately not yet implemented in BaCon.
        Use MID$(string$,i,1) instead.
Edit2:  Q$ = CHR$(34) , you guessed it, I'm sure.
Edit3:  BS$ = CHR$(92)
           backslashed quotes inside a quoted string are now recognized.
           spaces and newlines outside a quoted string are not printed anymore.

[vovchik]

Dear Rik.

Thanks. Here is something you can use for CHAR$:

DEF FN CHAR$(string$, i) = MID$(string$, i, 1)

I haven't tested but it should work...

All the best for the holidays and kind regards,
vovchik

PS. Tested and works nicely. Here is a function, too.

Attachments:

unjson-func-src.tar.gz (989 B)

[rikky]

Aj, Thanks for the example
Did not realise a json string could also have a lot of spaces and newlines to make it more human readable already.
Now you get a lot of double newlines and spaces, that makes it extra extra human readable, which is in fact less readable.
And in a FUNCTION the toggle4 for the CR$ can be replaced with a simple CHOP$(result$)

I have adapted the SUB above
And the FUNCTION below:

I noticed you like 4 spaces better then 2, so I made it a variable.
Also fixed a minor bug.
A backslashed quote \" inside a quoted string is now recognised.


DEF FN CHAR$(string$, i) = MID$(string$, i, 1)

' ------------------
FUNCTION UNJSON$(string$)
' ------------------

 LOCAL result$
 LOCAL counter
 LOCAL i
 LOCAL char$
 LOCAL toggle        : ' prevent double newline for '},'
 LOCAL toggle2 = 1   : ' first char, do not print newline
 LOCAL toggle3       : ' prevent printing space
 LOCAL quoted
 LOCAL backspace
 LOCAL Q$ = CHR$(34)  : ' quote
 LOCAL BS$ = CHR$(92) : ' backslash
 LOCAL tablen = 4
 
 FOR i = 1 TO LEN(string$)
   
   char$ = CHAR$(string$,i)
   
   IF toggle3 THEN
     IF char$ = " " OR char$ = "," THEN
       CONTINUE
     END IF
   END IF
   
   toggle3 = 0
     
   IF counter < 0 THEN counter = 0

   IF NOT(quoted) THEN
     IF char$ = NL$ OR char$ = " " THEN
       CONTINUE
     END IF
     IF char$ = "[" OR char$ = "{" THEN
       toggle3 = 1
       IF NOT(toggle2) THEN
         counter = counter + tablen
         'PRINT NL$ & SPC$(counter);
         result$ = result$ & NL$ & SPC$(counter)
         toggle = 0
         toggle2 = 0
         CONTINUE
       ELSE
         toggle = 0
         toggle2 = 0
         CONTINUE
       END IF  
     END IF
     
     toggle2 = 0
   
     IF char$ = "," THEN
       toggle3 = 1
       IF NOT(toggle) THEN
         'PRINT NL$ & SPC$(counter);
         result$ = result$ & NL$ & SPC$(counter)
         CONTINUE
       END IF
       toggle = 0
     END IF  
   
     IF char$ = "]" OR char$ = "}" THEN
       toggle3 = 1
       counter = counter - tablen
       'PRINT NL$ & SPC$(counter);
       result$ = result$ & NL$ & SPC$(counter)
       toggle = 1
       CONTINUE
     ELSE
       toggle = 0
     END IF  

   END IF
   
   toggle = 0
   toggle2 = 0
   
   IF char$ = Q$ THEN
     IF quoted THEN
       IF NOT(backspace) THEN
         quoted = 0
       END IF
     ELSE
       quoted = 1
     END IF
   END IF
   
   IF char$ = BS$ THEN
     IF quoted THEN
       IF backspace THEN
         backspace = 0  : ' \\
       ELSE
         backspace = 1
       END IF
     ELSE
       'should not happen
       backspace = 0
     END IF
   ELSE
     backspace = 0
   END IF
   
   'PRINT char$;
   result$ = result$ & char$
   
 NEXT i

 result$ = CHOP$(result$)
 
 RETURN result$
 
END FUNCTION



Thanks
 Rik.

[vovchik]

Dear Rik,

Thanks. The output is nice and clean now, and the function is useful.

With kind regards,
vovchik