Using splitByCharType to extract years of coverage in an 856 field

 GREL's splitByCharType() is actually quite a useful function. It takes a string, splits it up, and then groups consecutive like characters together in an array. Some of the more common like characters are all lowercase letters, all uppercase letters, all numbers, and all spaces. Special characters and punctuation are only grouped together with the exact same character (e.g. $$ would be grouped together, but $! would not.)

For example, for the string: $a300 pages ;$c20 cm, it'll fill the array this way:
Index                Element
0                        $
1                         a
2                        300
3                        <space>
4                        pages
5                         <space>
6                         ;
7                        $
8                         c
9                        20
10                     <space>
11                      cm