DRIVELEX -- "Lexfile Driver".  Adds DISABLE and ENABLE to BASIC.

Size: 277 bytes.

DISABLE "turns off" the specified lexfile. The lexfile is left in the
catalog chain, but it is removed from the lex chain, and changed to a
"D-LEX" (disabled lex) file, which has no effect on HP-71 operation.

ENABLE changes a disabled lexfile back into a "LEX" file, restores it
to the lexfile chain, and returns all of its effects (keywords and/or
poll handlers) to normal.

Having many lexfiles in memory is delightful because of the power it
gives you, but it's bad because it slows down the whole machine. For
optimum speed, DISABLE the lexfiles not needed at the moment, and
ENABLE them only as needed. This makes purging & reloading them
unnecessary.  DRIVELEX is a must for all lexfile users, especially
those with more memory than the bare HP-71.


*** DRIVELEX ***
(31AA8) File Header
(31B49) Poll Handler
(31B94) 71/09 DISABLE
(31BC0) 71/0A ENABLE
(31CF6) Next File Header