While ( condition ; function ; limit )

Allows to use a while in FileMaker

Average rating: 3.5 (89 votes) Log in to vote

Hisc - Show more from this author
noplace
http://nourl

Sample input:

Let([
$var = 0;
_ = while ( "$var<350000" ; "$var=$var+1"; "" )
];
$var
)

Sample output:

350000

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

/*

while ( condition ; function ; limit )

== SYNTAX == 
	while ( 
		"$var < 4" ;
		"$x = $x + 45 ; $var = $var + 1" ;
		30000
	)

== LIMIT ==
	optional parameter; if let empty, the limit will be considered 10,000 iteractions
	the objective of having a limit is to avoid unnecessary iteractions caused by errors in the logic of the while

== FUNCTION CODE ==
	- the function code is evaluated inside a let statement. 
	- its steps must be written as follows:
	"$x = $x & \"_again_\";
	 $var = $var +1"
	
	in this code:
	- quotes need to be escaped
	- the last line doesn't have a semicolon in the end

== REPETITION IN FORMULA ==
	this function has a repetition in the formula, as you can see that a portion of the formula is repeated 10 times. 
	That has the objective of allowing recursion over the usual limit of 9999

== TESTING ==
	1 while with 350,000 iteractions: aprox 35496 ms    |    35,496 seconds
	3,000 differente whiles with 1 iteractions each: aprox 5663 ms    |    5,663 seconds

== MODIFICATIONS ==
	according to the suggestion of "unin" from Japan, this version have:
	- limit scope
	- error checking for the function and the condition

*/

Let([

	// limit verifying
	functionLimit = Case ( IsEmpty ( limit ) ; 10000 ; GetAsNumber ( GetValue ( limit ; 1 ) ) ) ;
	actualIteration = GetAsNumber ( GetValue ( limit ; 2 ) );
	actualIteration = If ( IsEmpty ( actualIteration ) ; 1 ; actualIteration ) ;

	errorBo = If (
				actualIteration > 1 ; 0 ;
				Let ( [
					functionErrorBo = EvaluationError ( Evaluate ( "Let(["&function&"];\"\")"  ) );
					conditionErrorBo = EvaluationError ( Evaluate ( condition ) )
				];
					functionErrorBo or conditionErrorBo
				)
			);

	// break function?
	endBo = If ( (functionLimit < actualIteration) or errorBo = 1  ; 1 ; 0 );

	// execute formula 10 times, if needed

	endBo = Case (
				endBo ; 1 ;
				not Evaluate ( condition ) ; 1 ; // first verification if condition is true

				// try and re-check
				Let([
					_ = Evaluate ( "Let(["&function&"];\"\")" )
				];
					not Evaluate ( condition )
				); 1 ;
				
				// try and re-check
				Let([
					_ = Evaluate ( "Let(["&function&"];\"\")" )
				];
					not Evaluate ( condition )
				); 1 ;

				// try and re-check
				Let([
					_ = Evaluate ( "Let(["&function&"];\"\")" )
				];
					not Evaluate ( condition )
				); 1 ;

				// try and re-check
				Let([
					_ = Evaluate ( "Let(["&function&"];\"\")" )
				];
					not Evaluate ( condition )
				); 1 ;

				// try and re-check
				Let([
					_ = Evaluate ( "Let(["&function&"];\"\")" )
				];
					not Evaluate ( condition )
				); 1 ;

				// try and re-check
				Let([
					_ = Evaluate ( "Let(["&function&"];\"\")" )
				];
					not Evaluate ( condition )
				); 1 ;

				// try and re-check
				Let([
					_ = Evaluate ( "Let(["&function&"];\"\")" )
				];
					not Evaluate ( condition )
				); 1 ;

				// try and re-check
				Let([
					_ = Evaluate ( "Let(["&function&"];\"\")" )
				];
					not Evaluate ( condition )
				); 1 ;

				// try and re-check
				Let([
					_ = Evaluate ( "Let(["&function&"];\"\")" )
				];
					not Evaluate ( condition )
				); 1 ;

				// try and re-check
				Let([
					_ = Evaluate ( "Let(["&function&"];\"\")" )
				];
					not Evaluate ( condition )
				); 1 ;

				0
			 )
];
	Case (
		errorBo ;
			" - - - - - - - - - - ¶" &
			If ( EvaluationError ( Evaluate ( "Let(["&function&"];\"\")"  ) ) /* functionErrorBo */ ; "functionError; cannot evaluate: " & "Let(["&function&"];\"\")" & "¶" ; "" ) & If ( EvaluationError ( Evaluate ( condition ) ) /* conditionErrorBo */ ; "conditionError; cannot evaluate: " & condition ; "" ) 
			& "¶ - - - - - - - - - - ";
		functionLimit < actualIteration;
			"<reached limit of recursion at "&functionLimit&" repetitions; function stopped>" ;
		endBo ;
			"" ;
		while ( condition ; function ; List ( functionLimit ; actualIteration + 10 ) )
	)
)

this functions allows using a while function in FileMaker.
A limit of iterations may be specified; else, the limit will be set as 10000.
The function checks for error in the syntax of the condition and of the function

Comments

		Hisc, noplace Sep 7, 2015
I'm sorry: I created this function and it's rated 1.1. I'm unaware of the problems in it. Please, comment here what is wrong with it: - is the syntax failing? - is there already another custom function that does the same? - is it too slow? Too limited? - is it lacking in technical capabilities or technical definition?

		unin, Japan Sep 7, 2015
I wondered that yesterday I saw 5.0 on 2 votes become 2.0 on 40 votes now, but I think get it why. This function is difficult to use, since it become infinite loop very easily if the parameters not given correctly, then FM freezes while recursion reached at limit of 500,000 (about 50sec). Many of trier might think this as something "crasher". I like this type of challenge, but calling another recursive function in recursion makes easily up limit to about 50,000^2, isn't it? And although if the result is correct, freezing (not responding) about 50sec is not kind for user.

		Hisc, noplace Sep 8, 2015
I made some changes. I believe it will now be more suited to the needs. It checks for error in the condition and in the function; It establishes a limit for iteractions; thanks for the help, Unin

		Hisc, noplace Sep 8, 2015
Please, consider that the current rating â€“ 2.1 stars â€“ doesn't reflect in the actual code, which was heavily rewritten in 09/08/2015.

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

While ( condition ; function ; limit )

Comments

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