DO [device_] filename
This command allows you to execute a set of commands stored in a file (acting as an overlay).
It is intended to perform tasks dictated by a numberless file, which enables you to do many things whilst releasing memory once the tasks have been performed.
DO is actually very similar to the Toolkit II variant MERGE and will ensure that if the given file only contains numberless lines, the channel is closed afterwards.
It does however work just as well as MERGE on numbered files!
A numberless program is basically a set of SuperBASIC lines which do not have any line numbers. These can therefore best be entered with the aid of an editor program. Each line is loaded into the QL with the relevant command, and then executed (one line at a time), as if they had been entered from the command line (#0).
This therefore means that although they can call resident SuperBASIC PROCedures and FuNctions, you can only have in-line structures, such as IF…END IF and SELect ON…END SELect.
Once each line has been executed, it is lost and the memory occupied by that line released.
One advantage for pre JS ROMs is that if you use a numberless file to link resident keywords, such keywords can then be used in the same program which MERGEd the numberless file. For example, if you have a numberless file flp1_resident_bas such as:
a=RESPR(12000) LBYTES flp1_Toolkit,a: CALL a
you can then link and use the Toolkit commands in the same program by including a line such as:
110 DO flp1\_resident\_bas
On at least v2.28-v2.49 of Toolkit II, MERGE appears to work much better than DO at executing numberless files. If DO is entered as a direct command, none of the numberless lines are executed (compare MERGE which executes the first line), and if DO is part of a program, only the first line is executed (compare MERGE which executes all of the commands in the numberless file). This is fixed under SMS.