FASTNAMEFIELD:

This package contains code which speeds up UNPACKFILENAME,
FILECOMS, NAMEFIELD and FILENAMEFIELD at the expense of some space:
namely, when the value of FILECOMS or UNPACKFILENAME or NAMEFIELD
is required, it looks the atom up in a hash table and returns it
if found; if not found, it computes the value and stores it.

This turns out to make a significant difference to file package
manipulations.

If you tell GAINSPACE to clear the file package information,
it will also CLRHASH these arrays.

Larry Masinter