FileMaker Custom function: Remove characters that are not valid for use in a Let() variable name.

#SanitizeName.fmfn

/**
 * ============================================================================
 * #SanitizeName ( name )
 *
 * PURPOSE:
 * 		Remove characters that are not valid for use in a Let() variable name.
 *
 * RETURNS:
 *		Text that is a valid Let() variable name, if an error occurs, the original text is returned.
 *
 * PARAMETERS:
 *		name: any value that you want to use as the name parameter in the function: # ( name ; value )
 *
 * EXAMPLE:
 *		#SanitizeName ( "abc-123" ) = "abc123"
 *
 * DEPENDENCIES: none
 *
 * NOTES:
 *		This method is much faster than performing a substitute on all characters because the source text will probably
 *		only contain a small subset of invalid characters, if any at all.
 *
 * HISTORY:
 *		CREATED on 2014-MAR-04 by Daniel Smith dansmith65@gmail.com
 * ============================================================================
 */

// ~invalidCharacters are derived from this calculation:
// Quote ( Char ( 34 ) & Char ( 38 ) & Char ( 40 ) & Char ( 41 ) & Char ( 42 ) & Char ( 43 ) & Char ( 44 ) & Char ( 45 ) & Char ( 47 ) & Char ( 59 ) & Char ( 60 ) & Char ( 61 ) & Char ( 62 ) & Char ( 91 ) & Char ( 92 ) & Char ( 93 ) & Char ( 94 ) & Char ( 125 ) & Char ( 173 ) & Char ( 182 ) & Char ( 710 ) & Char ( 1548 ) & Char ( 1563 ) & Char ( 8208 ) & Char ( 8209 ) & Char ( 8220 ) & Char ( 8221 ) & Char ( 8222 ) & Char ( 8223 ) & Char ( 8249 ) & Char ( 8250 ) & Char ( 8260 ) & Char ( 8722 ) & Char ( 8725 ) & Char ( 8727 ) & Char ( 8800 ) & Char ( 8804 ) & Char ( 8805 ) & Char ( 9001 ) & Char ( 9002 ) & Char ( 12289 ) & Char ( 12296 ) & Char ( 12297 ) & Char ( 65104 ) & Char ( 65105 ) & Char ( 65108 ) & Char ( 65113 ) & Char ( 65114 ) & Char ( 65116 ) & Char ( 65120 ) & Char ( 65121 ) & Char ( 65122 ) & Char ( 65123 ) & Char ( 65124 ) & Char ( 65125 ) & Char ( 65126 ) & Char ( 65128 ) & Char ( 65282 ) & Char ( 65286 ) & Char ( 65288 ) & Char ( 65289 ) & Char ( 65290 ) & Char ( 65291 ) & Char ( 65292 ) & Char ( 65293 ) & Char ( 65295 ) & Char ( 65307 ) & Char ( 65308 ) & Char ( 65309 ) & Char ( 65310 ) & Char ( 65339 ) & Char ( 65340 ) & Char ( 65341 ) & Char ( 65342 ) & Char ( 65373 ) & Char ( 65380 ) )

Let ( [
	~invalidCharacters = "\"&()*+,-/;<=>[\]^}­\¶ˆ،؛‐‑\“\”\„\‟‹›⁄−∕∗≠≤≥〈〉、〈〉﹐﹑﹔﹙﹚﹜﹠﹡﹢﹣﹤﹥﹦\﹨\＂＆（）＊＋，－／；＜＝＞［＼］＾｝､" ;
	~removeCharacters = Filter ( name ; ~invalidCharacters ) ;
	~removeCharacter = Left ( ~removeCharacters ; 1 )
] ;
	If (
		IsEmpty ( ~removeCharacter ) ;
		name ;
		#SanitizeName ( Substitute ( name ; ~removeCharacter ; "" ) )
	)
)