How to make a multiline trigger

Posted by Whininguser on Fri 22 Oct 2010 05:52 PM — 13 posts, 45,102 views.

Whininguser Canada Fri 22 Oct 2010 05:52 PM #0

I've just read a lot on regexp, but I'm still lost...Any help would be appreciated.

How can I make a trigger fire only after the following happens:

You eat some food.
You are full.

Below is my failed attempt:

You eat some food\.\nYou are full\.

And I did have the "regular expression" box checked. Thanks for any help :)

Twisol USA Fri 22 Oct 2010 06:03 PM #1

You also need to have the "multiline" checkbox checked, with a value of 2. This lets MUSHclient know that the last two lines get parsed, not just the most recent.

Also, your regexp isn't anchored. That is, it could match on this:

ILLUSION: You eat some food.
You are full. (ILLUSION)

I believe you want to do something more like this, although I haven't used multiline triggers very extensively.

\AYou eat some food\.\nYou are full\.\Z

\A only matches at the start of the target, so there can't be anything before the "You". Likewise, \Z only matches at the end of the target, so there can't be anything after "full.".

Little note: When you use single-line triggers with regular expressions, you usually use ^ instead of \A, and $ instead of \Z. ^ matches the start of a line, and $ matches the end of one. Because MUSHclient guarantees that you're only going to get one line in a single-line trigger, this is safe and more idiomatic.

[EDIT] Disclaimer: This is untested, I don't have access to MUSHclient at the moment.

Whininguser Canada Fri 22 Oct 2010 06:18 PM #2

Your trick worked! Thank you for the fast and detailed reply!

Whininguser Canada Fri 22 Oct 2010 07:04 PM #3

I have another question. Suppose the output could be either

You eat some food.
You are full.

or just

You eat some food.

How can I make a trigger fire only when "You eat some food" happens but not when both lines happen?

Once again, my codes failed:


You feel slightly better\.(?!\nYou are now fully healed\.)


You feel slightly better\.\n(?!You are now fully healed\.)

I also tried placing (\A \Z) and (^ $) at different places.
Thanks for any help :)

Twisol USA Fri 22 Oct 2010 07:37 PM #4

Yep, this is a trickier situation. MUSHclient can't automatically deal with variable-line triggers, but your first example is two lines, and the second is one.

But let me ask you this. At the point where you get "You eat some food", how do you know what's coming next? You can't tell if that's all there was, or if there's still more coming (perhaps due to network latency). If you only got "You eat some food", you can't assume that's all there is.

Now, I assume your MUD has a prompt line that comes after pretty much everything. That means we have something a bit more like this:

You eat some food.
You are full.
100h 100m >

or

You eat some food.
100h 100m >

Now, this is what I would do: I would have one trigger for each of these lines. (Be sure to set "Keep evaluating", or other triggers won't be able to match the prompt.) Only the first is enabled to begin with. When it matches, it enables the other two. Next, if we get "You are full.", we set a variable to true. Lets call it is_full.

is_full = true

Notice that the fullness trigger doesn't actually do anything yet. We wait until the prompt trigger to do that:

if is_full then
  -- do stuff for being full
  is_full = false -- reset is_full for next time!
end
-- do more stuff whether we're full or not
EnableGroup("this_group_here", false) -- disable the triggers again

With this approach, by the way, you don't use multiline triggers. I call this technique a "gate" or a "guard", because you have to match one trigger before you can match another. It's a more general solution than multiline triggers: anything that can be done with a multiline can also be done with gates (and more besides).

[EDIT]: Lots of little fixes and additions to this post.

Nick Gammon Australia Forum Administrator Fri 22 Oct 2010 07:44 PM #5

This worked for me:


<triggers>
  <trigger
   enabled="y"
   group="forum"
   lines_to_match="2"
   match="\A(?&lt;!You eat some food\.)\nYou are full\.\Z"
   multi_line="y"
   regexp="y"
   send_to="2"
   sequence="110"
  >
  <send>********* Full.</send>
  </trigger>

  <trigger
   enabled="y"
   group="forum"
   lines_to_match="2"
   match="\AYou eat some food\.\n(?!You are full\.)\Z"
   multi_line="y"
   regexp="y"
   send_to="2"
   sequence="110"
  >
  <send>********* Eaten.</send>
  </trigger>

  <trigger
   enabled="y"
   group="forum"
   lines_to_match="2"
   match="\AYou eat some food\.\nYou are full\.\Z"
   multi_line="y"
   regexp="y"
   send_to="2"
   sequence="110"
  >
  <send>********* Eaten and full.</send>
  </trigger>
</triggers>

The last one is what you had before. The first uses a negative lookbehind assertion to check that "You are full" is not preceded by "You eat some food".

The second uses a negative lookahead assertion to check that "You eat some food" is not followed by "You are full".

For advice on how to copy the above, and paste it into MUSHclient, please see Pasting XML.

Nick Gammon Australia Forum Administrator Fri 22 Oct 2010 07:46 PM #6

Of course, these are all still 2-line triggers. So simply getting "You eat some food" will not cause anything to happen (because we don't know yet whether it will be followed by "You are full", or not).

Twisol USA Fri 22 Oct 2010 07:50 PM #7

Nick Gammon said:

Of course, these are all still 2-line triggers. So simply getting "You eat some food" will not cause anything to happen (because we don't know yet whether it will be followed by "You are full", or not).

This doesn't work for me, though:

/Simulate("You eat some food.\r\nHmm.\r\n")

If I remove the "Hmm." (but leave in the second \r\n), it works.

Whininguser Canada Fri 22 Oct 2010 08:07 PM #8

Problem solved. Thank you both!

Nick Gammon Australia Forum Administrator Fri 22 Oct 2010 08:27 PM #9

Twisol said:

This doesn't work for me, though: ...

I think this amended one works for that case:


<triggers>
  <trigger
   enabled="y"
   group="forum"
   lines_to_match="2"
   match="\A.*(?&lt;!You eat some food\.)\nYou are full\.\Z"
   multi_line="y"
   regexp="y"
   send_to="2"
   sequence="110"
  >
  <send>********* Full.</send>
  </trigger>

  <trigger
   enabled="y"
   group="forum"
   lines_to_match="2"
   match="\AYou eat some food\.\n(?!You are full\.).*\Z"
   multi_line="y"
   regexp="y"
   send_to="2"
   sequence="110"
  >
  <send>********* Eaten.</send>
  </trigger>

  <trigger
   enabled="y"
   group="forum"
   lines_to_match="2"
   match="\AYou eat some food\.\nYou are full\.\Z"
   multi_line="y"
   regexp="y"
   send_to="2"
   sequence="110"
  >
  <send>********* Eaten and full.</send>
  </trigger>
</triggers>

I needed to add ".*" to the negative assertions to absorb the stuff they there were not.

Twisol USA Fri 22 Oct 2010 08:40 PM #10

Nick Gammon said:
I needed to add ".*" to the negative assertions to absorb the stuff they there were not.

You'd probably want Keep Evaluating, too, or the .* lines will never be matched by lower-sequence triggers. Looks good! I still think multi-lines are pretty fiddly though.

Nick Gammon Australia Forum Administrator Fri 22 Oct 2010 09:25 PM #11

Twisol said:

You'd probably want Keep Evaluating, too, or the .* lines will never be matched by lower-sequence triggers.

Good point.

Whininguser Canada Thu 28 Oct 2010 11:27 PM #12

Edit:
The problem has been solved. Just in case anyone is replying to this post, I won't delete it. However, if you have a better solution, please post. Thanks :)
-------------------------------------------------

I have another long question: How can I make a trigger for a 3-line output like below?

1. The first two lines can be anything except "one" and "two"
2. The last line must be "last"

(In short: !one and !two and last)

Examples:

Match:
any
thing
last

No match:
one
two
last

No match:
any
two
last

I tried these and none worked:

\A(?!one)\n(?!two)\nlast\Z

\A(?!one)\n(?!two)\nlast.*\Z

\A(?<!one)\n(?<!two)\nlast\Z

\A(?<!one)\n(?<!two)\nlast.*\Z

Regexp was checked and multi-line was set to 3.

Thanks for any help :)

---------------------------------------------
Edit: This one finally worked :D

\A(?!one).*\n(?!two).*\nlast.*\Z