String Processing

FUNCTION	DEFINITION
= , ==, !=, <>, <=, >=, < , >	All common equality/inequality operators are applicable to strings and are applied in a case sensitive manner. In the following example x, y and z are of type string. (eg: not((x <= 'AbC') and ('1x2y3z' <> y)) or (z == x))
in	True only if $x$ is a substring of $y$. (eg: x in y or 'abc' in 'abcdefgh')
like	True only if the string x matches the pattern y. Available wildcard characters are `*' and `?' denoting zero or more and zero or one matches respectively. (eg: x like y or 'abcdefgh' like 'a?d*h')
ilike	True only if the string x matches the pattern y in a case insensitive manner. Available wildcard characters are '*' and '?' denoting zero or more and zero or one matches respectively. (eg: x ilike y or 'a1B2c3D4e5F6g7H' ilike 'a?d*h')
[r0:r1]	The closed interval $[r0,r1]$ of the specified string. eg: Given a string x with a value of 'abcdefgh' then: x[1:4] == 'bcde' x[ :5] == x[:10 / 2] == 'abcdef' x[2 + 1: ] == x[3:] =='defgh' x[ : ] == x[:] == 'abcdefgh' x[4/2:3+2] == x[2:5] == 'cdef' Note: Both r0 and r1 are assumed to be integers, where r0 <= r1. They may also be the result of an expression, in the event they have fractional components truncation will be performed. (eg: $1.67 \rightarrow 1$)
:=	Assign the value of x to y. Where y is a mutable string or string range and x is either a string or a string range. eg: y := x y := 'abc' y := x[:i + j] y := '0123456789'[2:7] y := '0123456789'[2i + 1:7] y := (x := '0123456789'[2:7]) y[i:j] := x y[i:j] := (x + 'abcdefg'[8 / 4:5])[m:n] Note: For options 7 and 8 the shorter of the two ranges will denote the number characters that are to be copied.
+	Concatenation of x and y. Where x and y are strings or string ranges. eg x + y x + 'abc' x + y[:i + j] x[i:j] + y[2:3] + '0123456789'[2:7] 'abc' + x + y 'abc' + '1234567' (x + 'a1B2c3D4' + y)[i:2j]
+=	Append to x the value of y. Where x is a mutable string and y is either a string or a string range. eg: x += y x += 'abc' x += y[:i + j] + 'abc' x += '0123456789'[2:7]
<=>	Swap the values of x and y. Where x and y are mutable strings. (eg: x <=> y)
[]	The string size operator returns the size of the string being actioned. eg: 'abc'[] == 3 var max_str_length := max(s0[],s1[],s2[],s3[] ('abc' + 'xyz')[] == 6 (('abc' + 'xyz')[1:4])[] == 4