Differences

This shows you the differences between two versions of the page.

--- zxt:extension:00000000:0001 [2021/03/11 22:00] – asie
+++ zxt:extension:00000000:0001 [2021/08/06 22:25] – asie
@@ Line 1: / Line 1: @@
-====== 00000000:0001 - #unlock extensions + #ifext ======
+{{tag>zxt:extension}}
+====== 00000000:0001 - #IFEXT ======
 ===== Information =====
@@ Line 11: / Line 13: @@
 | reading_must | MUST NOT | |
 | writing_must | MUST NOT | |
-| playing_should | MAY | If any extensions are recommended for gameplay. |
+| playing_should | MAY | If any #IFEXT calls are used in Objects with the described caveat for optional support. |
-| playing_must | MAY | If you're only using the #ifext portion, without #unlock extensions checks. |
+| playing_must | MAY | If any #IFEXT calls are used in Objects. |
 | editing_should | MUST NOT | |
@@ Line 21: / Line 23: @@
 ===== Description =====
-This extension adds two OOP commands which faciliate run-time detection of extensions on both ZZT 3.2 and ZXT-compatible implementations:
+This extension adds an OOP command which faciliates run-time detection of extensions on both ZZT 3.2 and ZXT-compatible implementations. The command is ''#IFEXT owner_id selector_id ...'', where owner_id and selector_id are specified as 32-bit and 16-bit hexadecimal numbers, respectively. If the extension with a given owner_id and selector_id is currently active within the execution context, the rest of the line is treated as a command.
-  * ''#UNLOCK'''s behaviour is extended as such: If ''#UNLOCK'' is immediately followed by the token ''EXTENSIONS'', the rest of the line is treated as a command.
+Keep in mind that to support ''#IFEXT'' as an optional extension, an '':IFEXT'' label SHOULD be provided to handle the situation in which this extension is not present.
-  * A new command, ''#IFEXT owner_id selector_id ...'' is provided. owner_id and selector_id are specified as 32-bit and 16-bit hexadecimal numbers, respectively. If the extension with a given owner_id and selector_id is currently active within the execution context, the rest of the line is treated as a command.
-The idea is that ''#UNLOCK EXTENSIONS ...'' will behave on ZZT 3.2-conformant implementations just like ''#UNLOCK'' would - by unlocking the Object, skipping the command being executed. On the flip side, if the extension is not active, ''#UNLOCK EXTENSIONS'' will work as it would on a ZZT 3.2-conformant implementation - providing compatibility in both directions.
+===== Example usage =====
-==== Example usage ====
+==== Simple scenario ====
 <code>
-#unlock extensions foundone
+#ifext 00000000 0001 found
+:found
+Extensions found!
+#end
+:ifext
 Extensions not found.
 #end
-:foundone
+</code>
-#ifext 00000000 0001 foundtwo
-Unlock OK, but not ifext? - Should not happen
+==== Two touch codepaths ====
+<code>
+@Interactive
+#ifext 00000000 0001 zap touch
+:ifext
+#end
+:touch
+I found nothing...
+#end
+:touch
+I found IFEXT support!
 #end
-:foundtwo
-Unlock and ifext OK! Your implementation is correct.
 </code>
-===== Implementations =====
+==== Two touch codepaths (#BIND workaround) ====
-  * [[https://github.com/OpenZoo/ClassicZoo/commit/5e7d49129ee66bf235bd562ddc48bfc407fe6eef|Reference implementation]] (0BSD license, RoZ-based, OOP.PAS edits apply)
+If the code above is bound, '':TOUCH'' might end up being zapped multiple times. This code takes care of that:
+<code>
+@Interactive
+#send init
+#end
+:init
+#ifext 00000000 0001 zap touch
+:ifext
+#end
+:touch
+I found nothing...
+#end
+:touch
+I found IFEXT support!
+#end
+</code>
+An alternative, more advanced technique is pre-setting the instruction pointer in an external editor.
+===== Implementations =====