The Snarf( s, cset ) command returns the prefix of the string s consisting of characters from the character set, cset.

The character set, cset, may be specified either as a string, whose characters are taken to be those in the character set, or a symbol, such as lower which represents the set of lowercase alphabetic characters.

All of the StringTools package commands treat strings as (null-terminated) sequences of $8$-bit (ASCII) characters.  Thus, there is no support for multibyte character encodings, such as unicode encodings.

$\mathrm{with}\left(\mathrm{StringTools}\right)\:$

$\mathrm{Snarf}\left(''abcdEFGHijklm''\,'\mathrm{lower}'\right)$

$''abcd''$

$\mathrm{Snarf}\left(''abcdEFGHijklm''\,''abcdefghijklmnopqrstuvwxyz''\right)$

$''abcd''$

$\mathrm{Snarf}\left(''abcdEFGHijklm''\,''xyzab''\right)$

$''ab''$

$\mathrm{Snarf}\left(''relative/path/to/some/file''\,'\mathrm{\alpha }'\right)$

$''relative''$

The StringTools[Snarf] command was introduced in Maple 18.

For more information on Maple 18 changes, see Updates in Maple 18.