B00_fextsSourceSets of file extension sets.
The type for sets of file extensions.
The type for files mapped by their extension.
v exts is a set for the given extensions.
ext e is the set that containes only e.
find_files exts m selects from m the files that have an extension in exts.
all_files m is concatenation of the list of files in m in no particular order.
exists_file exts fm s is true iff find_file fm s is not empty.
( + ) is B0_std.String.Set.union.
( - ) is B0_std.String.Set.diff.
image is ".eps", ".gif", ".ico", ".jpeg", ".jpg", ".pdf", ".png", ".ps" and ".tiff".