System Functions

MSK( ) Scan String for Mask

Format	MSK(string$,mask$[,ERR=stmtref])   Where:
	mask$				String containing the pattern / mask definition. If this value is null, then the previously used pattern is reused. String expression.
	stmtref				Program line number or statement label to which to transfer control.
	string$				String to search. Maximum string size 8kb.
Returns	Integer reporting starting offset.
Description	Use the MSK( ) function to scan a string looking for a specific pattern of characters. The value returned is an integer reporting the starting offset of the longest string matching the given mask or pattern. The pattern defines the mask as a regular expression or series of characters, some of which have a special meaning. The following table lists those characters and their meanings. Combinations are allowed.
		Mask Character.					Format in Pattern$	Search
		^		Caret			At start of regular	To find a match with the start of the
							expression.	string being searched.
		$	Dollar Sign$				At end of regular	To find a match with the end of the
							expression.	string being searched.
		.		Period				To find a match with any character
							String of characters	To define a sub-expression to match.
		( string )				(or other codes) enclosed in parentheses.
		[ string ]					String enclosed in	To find a match with any character in
							square brackets	that string.
							Square bracketing	To find a match with any character
							combined with a	except the characters in the string; e.g.,
		[^string]					caret ^ as the first	[xyz] matches x, y,or z, while
							character of the	[^xyz] matches a, b, c, but not
							string.	x, y, or z.
		–	Dash				2 characters	To specify a range.
							separated by – dash.
							Combination of dash	To form expressions: e.g., [a-bd-z] to
		[str–ing]					within string in	search for a match with any lower case
							square brackets.	letter except c.
		Mask Character.					Format in Pattern$	Search
								To search for zero or more occurrences of
							At the end of a	the character (or sub-expression);e.g., in
		*	Asterisk				character (or	fo*, the *operates on the o; it
							sub-expression).	matches f, fo, foo etc.. but doesn't match fa. The expression f(at)* matches f, fat, fatat, fatatat, etc.
							At the end of a	To find a match with 1 or more
		+		Plus Sign			character (or	occurrences of that character (or
							sub-expression).	sub-expression); e.g., fa+ matches fa, faa, faaa, etc. but not f.
							At the end of a	To indicate that it is optional. For
		?	Question Mark				character (or	example, colou?r matches color or
								colour and sea(horse)? matches
							sub-expression).	sea or seahorse.
							Separating two	To find a match for either of the two
		|		Vertical Bar			characters (or	characters (or sub-expressions); e.g.,
								c(at)|(ow) matches cat or cow and
							sub-expressions).	at|(nd) matches at or and.
								To indicate that the character that
		\		Backslash			Preceding a mask
							character.	follows is to be taken literally; e.g., to search for multiple asterisks use \**.
	The MSK( ) function returns the starting offset in the search string$ (where it matches the pattern specified). The MSL system variable and TCB(16) return the length of the string found.
*Note*	When the 'TL' (Thoroughbred LIKE) system parameter is OFF, the LIKE operator uses the same pattern matching that MSK( ) does. With the 'OM' (Old Mask) System Parameter ON, MSK( ) behaviour is compatible with the UNIX GREP command.
See Also	MSL System Variable TCB( ) Return Task Information 'TL' System Parameter, 'OM' System Parameter. Operators
Example	->PRINT MSK("my name is Foxxy","[A-Z][a-z]*"),MSL 12 5   Here, MSK( ) reports the starting offset. (F, the 12th character, is the first uppercase character.) MSL( ) reports the length of the string. (Foxxy is 5 characters long.)