By JGH, May-2006.
It is common for programs to put commonly used data in DATA statements which are then read into a set a variables at startup. A classic example is the names of months:
DIM mon$(12) RESTORE FOR mon%=1 TO 12:READ mon$(mon%):NEXT mon% DATA Jan,Feb,Mar,Apr,May,Jun,Jul,Aug,Sep,Oct,Nov,Dec
This has a few immediate disadvantages:
You can avoid the DATA pointer being modified by doing the following:
DIM mon$(12) mon$() = "","Jan","Feb","Mar","Apr","May","Jun","Jul","Aug","Sep","Oct","Nov","Dec"
but the data is still held in memory twice.
An alternative for small bits of fixed data like this is to hold them in a string:
This has several advantages:
This can even be done for data that at first sight doesn't look like fixed data:
DEF FNmonth(mon%) \ \ =MID$("JanuaryFebruaryMarchAprilMayJuneJulyAugustSeptemberOctoberNovemberDecember", \ \ VALMID$("010816212629333743525967",mon%*2-1,2), \ \ VALMID$("785534469788",mon%,1))
The first VALMID$ string is a series of initial start positions of the month name strings for each month. The second VALMID$ string is the length of each month name.
Note: the example functions only give valid results for valid month numbers.