feat: add ON GOTO and ON GOSUB examples

Author: boriel

Diff for: examples/on_gosub.bas

@@ -0,0 +1,20 @@
+#include <input.bas>
+
+10 PRINT "Enter a number from 0 to 9"
+   PRINT "Only values 0, 1 and 2 will"
+   PRINT "be dispatched"
+   PRINT "> ";
+   LET X$ = INPUT(1)
+   IF X$ < "0" or X$ > "9" THEN GOTO 10
+20 LET ok = 0
+   ON VAL(X) GOSUB 50, 100, 150: IF ok THEN END
+   GOTO 10
+30 PRINT "Invalid choice: "; X
+40 RETURN
+50 PRINT "You chose option 0": LET ok = 1
+60 RETURN
+100 PRINT "You chose option 1": LET ok = 1
+110 RETURN
+150 PRINT "You chose option 2": LET ok = 1
+160 RETURN
+

Diff for: examples/on_goto.bas

@@ -0,0 +1,18 @@
+#include <input.bas>
+
+10 PRINT "Enter a number from 0 to 9"
+   PRINT "Only values 0, 1 and 2 will"
+   PRINT "be dispatched"
+   PRINT "> ";
+   LET X$ = INPUT(1)
+   IF X$ < "0" or X$ > "9" THEN GOTO 10
+20 ON VAL(X) GOTO 50, 100, 150
+30 PRINT "Invalid choice: "; X
+40 GOTO 10
+50 PRINT "You chose option 0"
+60 END
+100 PRINT "You chose option 1"
+110 END
+150 PRINT "You chose option 2"
+160 END
+