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--- preprocessor [2018/02/13 20:06] – wolfgangriedmann
+++ preprocessor [2018/02/14 04:52] (current) – wolfgangriedmann
@@ Line 3: / Line 3: @@
 The preprocessor is an unique feature of the X# compiler. In the Clipper times, the preprocessor was used to implement the commands (they were mapped to function calls), and in the VO times the preprocessor was present, but very few people used it.
-Now, in the X# compiler it is again a very powerful tool. It can be used to implement commands for FoxPro compatibility:
+The simpliest statement is the #ifdef, usable for conditional compilation, and very helpful in the migration from VO:
+<code>#ifdef __XSHARP__
+  super:__FocusPage( int( nIndex ) )
+#else
+  super:__FocusPage( nIndex )
+#endif</code>
+Now, in the X# compiler it is again a very powerful tool. It can be used to implement commands for compatibility with xBase languages like Clipper, FoxPro and Harbour:
 <code>#command USE <db>     ;
      [VIA <rdd>]        ;
@@ Line 16: / Line 23: @@
 <code>USE "C:\dbf\customer.dbf" VIA "DBFCDX" ALIAS test</code>
 Source: [[https://www.xsharp.info/forum/public-chit-chat/561-managed-dbf-using-x-language?start=12|https://www.xsharp.info/forum/public-chit-chat/561-managed-dbf-using-x-language?start=12]] - the second message by Chris Pyrgas
+The development team has ported a Harbour app to X# using the preprocessor to translate the way @x,y SAY...GET  commands to their own function calls, making it work without changing the original code.
 But it can also be used to write less code for MVVM ViewModels: