The Insert(s, position, t) command inserts a string t into the string s at position. The value of position must be an integer in the range . Position  is the position before the first character of s; position  is the position after the first character of s; position  is the position after the second character of s; and so on. Thus, Insert( s, 0, t ) is equivalent to , while Insert( s, length( s ), t ) is equivalent to .

Error, (in StringTools:-Insert) string index `5' out of range