The most important new feature of EDT V17.0A compared to the preceding versions is the capability to process files coded in Unicode. This support was introduced in order to achieve the following two aims:
Users who want to process files coded in Unicode should be able work in an easy-touse environment. This includes, for example, the ability to edit differently coded files in various EDT work files simultaneously as well as the elimination of the line length restriction (previously 256 characters).
Users who want to continue to edit files coded in 7-bit or 8-bit character sets as before should be able to make use of functions and interfaces compatible with EDT V16.6B. This relates, in particular, to the execution of EDT procedures and operations at the subroutine interfaces.
The increase in the permitted record length together with the fact that a Unicode representation is used internally in the work files means that the compatibility of all the various interfaces at which users previously had direct access to the internal EDT data cannot be maintained. This applies to the old L mode subroutine interface, the former @RUN interface and the Locate mode of the IEDTGLE interface. It is therefore no longer possible to use these interfaces if you wish to make use of the new functionality.
Nevertheless, programs which simply use the EDT subroutine interfaces to permit their users to edit files without having to exit the current program should also be able to operate with Unicode files with the smallest possible number of changes.
This is possible because it is now possible to run EDT V17.0A in two modes:
In Unicode mode which has been extended for the processing of Unicode files but in which there are certain incompatibilities, in particular at the level of the subroutine interface.
In compatibility mode which offers the full functionality of EDT V16.6B but which does not support the processing of Unicode files, increased record lengths or locally configured character sets.
For more information on the operating modes and the way they interact see chapter 11.