ExtractListFromHtml ( AnyText ; Html ; theStartTag ; theEndTag )

Recursive function, returns a list of every possible subset, of any length, of characters contained between theStartTag and theEndTag.

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Gennaro BONATESTA - Show more from this author
Tenuta TRESCA
https://www.tresca.it

Sample input:

ExtractListFromHtml (
"LIST" & ¶ ;
"span class=\"text\">Anna Fontana/span> " & ¶ &
"span class=\"text\">Annamaria Di Pinto/span> " & ¶ &
"span class=\"text\">Antonio Palumbo/span>" ;
"span class=\"text\">" ;
"/span>"
)

Sample output:

LIST
Anna Fontana
Annamaria Di Pinto
Antonio Palumbo

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

//	AUTHOR
// Gennaro BONATESTA 2019-01-29
// http://www.briandunning.com/cf/2214

//	START FROM
// ALoopingDemo v1 created 2015-03-21 by Doug Staubach
// http://www.briandunning.com/cf/1755

//	DEPENDENCIES
// ParseData ( theText ; theStartTag ; theEndTag ; theOccurance )
// https://www.briandunning.com/cf/559

//	FORMAT
// ExtractListFromHtml ( AnyText  ; Html ; theStartTag ; theEndTag )  

//	DESCRIPTION
// Recursive function, returns a list of every possible subset, of any length, of
// characters contained between theStartTag and theEndTag. 

Case (

	// First cycle through the loop, so the counter does not exist yet
	not $LoopCount ;
	Let ( [
		// On the first loop, initialize internal variables and start first recursion
		$Times = PatternCount ( Html ; theStartTag ) ;
		$OtherVariable = "" ; 
		$LoopCount =  1 
		] ;
	// This is the first recursion -- the function just calls itself,
	// with the same parameter(s) that the user entered
	ExtractListFromHtml ( AnyText  ; Html ; theStartTag ; theEndTag ) 
	) ; 

	// On the second cycle through the loop, the counter will be set to 1
	// the third cycle the counter will be set to 2, then 3 and so forth
	$LoopCount < $Times + 1 ;
	Let ( [
		// This is where you would place the majority of your detailed work
		// (inside the top part of the LET statement)
		// The last line should increment your loop counter
		~ExtractedText = ParseData ( Html ; theStartTag ; theEndTag ; $LoopCount ) ;
		AnyText = AnyText & ~ExtractedText & If ( $LoopCount ≥ $Times ; "" ; "¶" ) ;
		$OtherVariable = "" ; 
		$LoopCount = $LoopCount + 1 
		] ;
	// After finishing each step, we recurse again
	ExtractListFromHtml ( AnyText ; Html ; theStartTag ; theEndTag )
	) ; 

	// We have now completed the last cycle through the loop
	$LoopCount ≥ $Times + 1 ; 
	Let ( [
		AnyText = AnyText ;
		// before exiting the last step, we will release all variables
		// (we do this to keep memory clean)
		$LoopCount = "" ; 
		$OtherVariable = ""
		] ;
	// The very last line is the function return value
	// If the function needs to return a calculated result
	// (text, number or date) -- put that value on the line below
	// If the function only sets global memory variables (for example, a
	// function called by an event trigger) -- type True on the line below
	AnyText
	)
)

/*
WHY THIS TECHNIQUE IS NEEDED:

1. FileMaker custom functions do not support looping statements (Do, While, For-Next) or line-jumping (GoTo).

2. FileMaker custom functions do not support the use of "optional parameters" (parameters that do not have to be included with the function call), which might help to simulate some of the above functions.

The code demonstrated in this function shows how to create a conditional loop using Case(), Let(), Recursion, and a local script variable ("$", not "$$").

Using this technique, you can create a loop with the ability to perform different actions at each "step" in the loop (1, 2, 3, etc.).

DEPENDENCIES:

1. Tested using FileMaker 17 - should work from v15.

2. Have dependencies on custom function ParseData ( theText ; theStartTag ; theEndTag ; theOccurance ) - https://www.briandunning.com/cf/559.

NOTES:

1. I did not invent this technique. It has been in existence for a long time. I am just showing a simple example for people who want to include some sort of looping mechanism inside of a FileMaker custom function, and haven't tried this method before.

2. FileMaker has a limit of 10,000 nested recursions per function call. Therefore, it makes sense to use this technique for an internal loop counter, but it is not good to use this technique for looping through large data sets (in that case, you might want to check out the looping capabilities of FileMaker scripts, which have fewer limits).

3. You will need a copy of "FileMaker Advanced" to *create* a custom function, but functions that have been created with "FileMaker Advanced" and saved into a database, can be freely used by "FileMaker Pro" clients who access that database.

*/

WHY THIS TECHNIQUE IS NEEDED:

1. FileMaker custom functions do not support looping statements (Do, While, For-Next) or line-jumping (GoTo).

2. FileMaker custom functions do not support the use of "optional parameters" (parameters that do not have to be included with the function call), which might help to simulate some of the above functions.

The code demonstrated in this function shows how to create a conditional loop using Case(), Let(), Recursion, and a local script variable ("$", not "$$").

Using this technique, you can create a loop with the ability to perform different actions at each "step" in the loop (1, 2, 3, etc.).

DEPENDENCIES:

1. Tested using FileMaker 17 - should work from v15.

2. Has dependencies on the custom function ParseData ( theText ; theStartTag ; theEndTag ; theOccurance ) - https://www.briandunning.com/cf/559.

NOTES:

1. I did not invent this technique. It has been in existence for a long time. I am just showing a simple example for people who want to include some sort of looping mechanism inside of a FileMaker custom function, and haven't tried this method before.

2. FileMaker has a limit of 10,000 nested recursions per function call. Therefore, it makes sense to use this technique for an internal loop counter, but it is not good to use this technique for looping through large data sets (in that case, you might want to check out the looping capabilities of FileMaker scripts, which have fewer limits).

3. You will need a copy of "FileMaker Advanced" to *create* a custom function, but functions that have been created with "FileMaker Advanced" and saved into a database, can be freely used by "FileMaker Pro" clients who access that database.

Comments

		Santiago Herrera Mar 26, 2019
It works very nice, but you need to change some functions names like "ContaRicorrenze" by "Patterncount" "Casi" by "Case" "Dichiara" by "Let" tks a lot for this function

		Gennaro BONATESTA, Tenuta TRESCA Feb 26, 2020
I changed the names!

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

ExtractListFromHtml ( AnyText ; Html ; theStartTag ; theEndTag )

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