The SUBSTR pseudovariable assigns a string value to a substring,
specified by y and z, of x. The remainder
of x is unchanged. Assignments to a varying string do not
change the length of the string.
>>-SUBSTR(x,y-+----+-)----------------------------------------->< '-,z-'
- x
- String-reference. x must not be a numeric character.
- y
- Expression. y expression that can be converted to a FIXED BINARY value which specifies the starting position of the substring in x.
- z
- Expression. z specifies the length of the substring in x. It can be converted to a real fixed-point binary value. If z is zero, a null string is returned. If z is omitted, the substring returned is position y in x to the end of x.
y and z can be arrays only if x is an array.