The use of the underscore "_" key in an identifier when dimensioning a constant or variable results in RTIWIN error S16 - "Missing Letter" or S20 - "Expected End of Statement". This is due to the fact that, under MS-Windows when the underscore "_" key is pressed, it generates a HEX(A0) (equivalent to an "underline space"), rather than a HEX(5F) (equivalent to an underscore) in NPL.
To modify this situation, use the following program commands in a PREBOOT or BOOT program:
10 DIM KEYMAP$576
:; underline fix×
: STR(KEYMAP$,1+VAL(HEX(5F))/8,1)=AND HEX(7F)×
:; not a SF key×
The above code wll replace the underline space with a back arrow "ß" common on previous releases of NPL. Please note that this only affects Windows version of the RunTime, such as RTIWIN and RTIWIN32. As an alternative solution, the NPL Utilities may also be used to modify the keyboard file.
NOTE: For more details related to the PREBOOT program, refer to Section 4.4.8 of the MS-DOS Supplement.