Data commit

Task/Assertions/XPL0/assertions.xpl0

@@ -0,0 +1,10 @@
+proc Fatal(Str);        \Display error message and terminate program
+char Str;
+[\return;                uncomment this if "assertions" are to be disabled
+SetVid(3);              \set normal text display if program uses graphics
+Text(0, Str);           \display error message
+ChOut(0, 7);            \sound the bell
+exit 1;                 \terminate the program; pass optional error code to DOS
+];
+
+if X#42 then Fatal("X#42");