AllTextCombinations ( theText ; stackDepth )

recursively subsets a text string into [almost] all possible subsets, return delimited, debatably suitable for multi-line key foreign side of Portal search relationships

Average rating: 3.8 (38 votes) Log in to vote

Jeremy Bante
OshVay Systems, Inc.
http://www.oshvay.com

Sample input:

AllTextCombinations( "abcd"; 0)

Sample output:

abcd
abc
ab
a
b
bc
b
c
bcd
bc
b
c
cd
c
d

Function definition: (Copy & paste into FileMaker's Edit Custom Function window)

/*AllTextCombinations(theText; stackDepth) returns all sequential character combinations for theText by recursively calling itself with one character less of theText; stackDepth should be set to 0 when used, or whatever the current stack depth is if called from another custom function.
When theText is longer than (15 - stackDepth) characters long [,longer than 15 characters if called with stackDepth = 0], AllTextCombinations() will evaluate successively smaller blocks of theText independently of each other; with a beginning stackDepth = 0, AllTextCombinations() will only evaluate for the first 105 characters in theText. Should the controlled stack reach it's limit (stackDepth > 14), it will simply return theText and theText without it's right-most and left-most characters.*/

Case(

    //if theText is trivial (one-character long or shorter)...
  Length( theText) < 2;
    //just return theText
  theText;

    //if the function call stack is full...
  stackDepth > 14;
    //return theText and theText without it's right-most and left-most characters
  theText
  & "¶" &
  Left( theText; Length( theText) - 1)
  & "¶" &
  Right( theText; Length( theText) - 1);

    //if theText is too long...
  Length( theText) > 15 - stackDepth;
  theText
  & "¶" &
    //evaluate the first acceptable block...
  AllTextCombinations(
    Left( theText; 14 - stackDepth);
    stackDepth + 1
  )
  & "¶" &
    //evaluate and possibly subdivide the remaining block
  AllTextCombinations(
    Right( theText; Length( theText) - 14 + stackDepth);
    stackDepth + 1
  );

    /*if theText is not trivial,
    the function call stack is not full,
    and theText is not too long...*/
  theText  //return theText...
  & "¶" &
  AllTextCombinations(  
    Left( theText; Length( theText) - 1);
    stackDepth + 1
  )  //return all combinations of theText less the right-most character...
  & "¶" &
  AllTextCombinations(
    Right( theText; Length( theText) - 1);
    stackDepth + 1
  )  //...and return all combinations of theText less the left-most character
)

This is a revised version of Peter Gort's AllTextCombinations(theText) function designed to better handle FileMaker's limited function-call stack. It _will_not_ work perfectly for text of any length, but it should work pretty well for shorter strings. Unfortunately, it is very slow and inefficient at what it does in comparison to the oAzium Portal Filter plug-in: the size of the result roughly doubles for each of the first 15 characters! Furthermore, this function will only evaluate "properly" for the first 105 characters of theText.

Comments

		Kevin Smith, Cloud May 3, 2010
Hi A script that called this function works fine using FM 10 Advanced. When running in FM Advanced 11.0v1 it causes FileMaker to crash. I have not troubleshooted the circumstances under which this occurs. Regards Kevin Smith

		Chris Page, San Jose, CA Feb 12, 2014
Try this one: http://www.briandunning.com/cf/784

Note: these functions are not guaranteed or supported by BrianDunning.com. Please contact the individual developer with any questions or problems.

AllTextCombinations ( theText ; stackDepth )

Comments

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