STRING FUNCTIONS

All functions that take a position default to the first character in a field if not specified.
All "is" functions return "1" for true and "0" for false.
	x=isalpha(fld [, pos])
		Is the character at the position given a letter?
	
	x=isdigit(fld [, pos])
		Is the character at the position given a number?
		
	x=isalnum(fld [, pos])
		Is the character at the position given a letter or number?
	 
	x=isspace(fld [, pos])
		Is the character at the position given a whitespace character?
		' ', '\t', '\n', '\r', '\v', '\f' 
	
	x=islower(fld [, pos])
		Is the character at the position given lowercase?
	
	x=isupper(fld [, pos])
		Is the character at the position given uppercase?
	
	x=isxdigit(fld [, pos])
		Is the character at the position given a hexadecimal character?
		'0'-'9', 'A'-'F'
	
	x=iscntrl(fld [, pos])
		Is the character at the position given a control character?
		ASCII codes 0x00 (nul) - 0x1f (US), and 0x7f (del)
	
	x=isprint(fld [, pos])
		Is the character at the position given a printable character?
		ASCII codes greater than 0x1f (US) not including 0x7f (del)
	
	x=ispunct(fld [, pos])
		Is the character at the position given a punctuation character?
	
	x=isgraph(fld [, pos])
		Is the character at the position given a character with a graphical representation?
		The characters with graphical representation are all those characters than can be printed (as determined by isprint) except for space.
	
	x=tolower(fld [, pos])
		Return the character at the position given as a lowercase character.
	
	x=toupper(fld [, pos])
		Return the character at the position given as an uppercase character.
	
	str=strtolower(fld)
		Return the entire string converted to lowercase.
	
	str=strtoupper(fld)
		Return the entire string converted to uppercase.
	
	aa=ltrim(fld)
		left trim
	
	aa=rtrim(fld)
		right trim
	
	aa=trim(fld)
		trim both left and right