Zugg Software :: View topic - Feature suggestion: More database record functions

Wizard Joined: 14 Aug 2004 Posts: 1269

I was reading this in the zMUD forum:

Magician Joined: 28 Jan 2007 Posts: 430

I wholeheartly support this idea!! Cool

Prog

Posted: Wed Oct 03, 2007 4:26 am

I'll definitely take a look at this. But also keep in mind that the full Lua support in v2.0x treats CMUD database variables directly as Lua tables, so you can also use any of the existing Lua methods for working with these "tables". Lua doesn't have all of the routines that Python has, so I'll definitely give the list you posted some consideration in the future. I was hesitant to do this kind of stuff in the past because CMUD database variables were so inefficient, but now that we have hashed tables in 2.0x, it's worth adding more support for these useful "tables" (or "dictionaries", whatever terms you prefer).

Btw, you might not be aware that in CMUD (even in 1.34 I think), you can use the syntax {@varname} in a trigger pattern even if @varname is a database variable! We all know that for string lists this works, but some people don't know that when using a database variable, CMUD converts this to {key1|key2|key3...} just like your %dbkeys example. So, you can already do something like this:

Wizard Joined: 14 Aug 2004 Posts: 1269

Posted: Wed Oct 03, 2007 2:32 pm

SubAdmin Joined: 18 Nov 2001 Posts: 5182

The only addition I really need so far is to be able to do a key lookup based on value. There just are so many things where both key and values are paired and unique. The alternative to being able to do such a lookup quickly is to use 2 variables, one mirroring the others for position. Currently I commonly use a combination of %expanddb and %regex, but there are some very blatant performance hits for doing that way.

Something like this:
#ADDKEY blah {Zugg=Great|Chiara=Wonderful|Vijilante=Needy}
#SHOW %keyof(@blah,"Wonderful")

Would display "Chiara".

Wizard Joined: 14 Aug 2004 Posts: 1269

Edited quoted text for brevity. Italics mine.

Wizard Joined: 14 Aug 2004 Posts: 1269

Posted: Thu Oct 04, 2007 1:10 am

A language war'd be pretty pointless since CMUD is going to fully support Python via WSH in the future, so no worries on that one :) I wouldn't advise trying to use it yet, though Seb - the only thing you can edit at the moment is variables. It might be possible to do some interesting stuff with expression triggers, but it'd be way more complex than just using the new zs object when it's made available via WSH.

Regardless, I wasn't refuting that Python's a good system - it must be, or people wouldn't use it. I was following from Zugg's comment about Lua being able to manipulate CMUD's database and string list variables, and that despite what Zugg said about Lua not including all those operations by default, it's still capable of them.

Wizard Joined: 14 Aug 2004 Posts: 1269

Right. Now I remember why I never got into using other scripting languages in zMUD (plus I thought (probably wrongly) that they would be slower). Maybe I'll do some quick performance comparison tests though when the next CMUD version is out. It might be interesting. The problem I suppose is making a variety of benchmark tests if one was do a thorough comparison.

From an academic perspective I'm still interested in the answers to those two questions in italics in the section where I quoted you though.

Posted: Thu Oct 04, 2007 2:23 am

Oh, I didn't realise there were questions there, I just thought you'd truncated my post.

1) Short answer: yes. Long answer: deleting a value without deleting the key doesn't make sense, at least not as I understand it. Variables aren't initialised - they simply don't exist if they point to nil. It's impossible for a variable to have no value (counting nil as a value).

2) No, it wouldn't create a copy - I wasn't sure what the Python function was for - but again, you can do that simply with for.

Wizard Joined: 14 Aug 2004 Posts: 1269

Posted: Thu Oct 11, 2007 10:12 pm

I have added the following functions to v2.06:

Apprentice Joined: 11 Sep 2005 Posts: 124

Awesome, I'll definately be making use of these new functions in my future scripting!

Wizard Joined: 14 Aug 2004 Posts: 1269

Posted: Fri Oct 12, 2007 2:14 am

Well, @dbitems would certainly be easy to add, although I'm still a bit perplexed by your example and why you'd ever need it. You could also just do a %replace(@dbvar,"=","|") to get it already, although I guess that wouldn't work if there were embedded = within items.

The problem with %dbitems is that you would lose any sort of index reference to the original variable. With %iskey and %isvalue, you get the Index value that you can use with %item to index into the %dbkeys and %dbvalues list. With @dbitems, you just end up with a string list with no structure, and I'm just having a hard time seeing the usefulness of it.

I'm not going to do the %dbitem function idea though...that's just too complex and un-intuitive. And it shouldn't be needed given the other new functions that were added. Your first example is the same as %db(@dbvar,"Tom"), your second example is the same as %item(%dbkeys(@dbvar),%isvalue(@dbvar,"Dick|Harry")) and your 3rd example is just a concat of these two.

And no, you cannot have non-unique keys...that's the whole purpose of having hashed database variables. These work like tables in Lua, or associative arrays in Perl. The key *must* be unique.

Wizard Joined: 14 Aug 2004 Posts: 1269

Posted: Fri Oct 12, 2007 3:01 am

There was mention of using %expanddb in the trigger pattern to get the effect that Seb describes, but it doesn't work.

%item(@dbvar,%ismember("Dick",%dbitems(@dbvar))) doesn't seem like it'll do what you want. Like Zugg says, the stringlist returned by your %dbitems won't be linked in any way to the actual variable - there's no way to put the %ismember number back into the variable, because if your first key is a stringlist of 20 items, then the second key will have an index of 22, which is meaningless to the %item function. The functionality you seem to want (give it a value, it gives you the key) is already easily done with %item(@dbvar,%isvalue(@dbvar,"something")).

However, one thing. %isvalue returns "the key" that's associated with a value, but values don't need to be unique - it's possible that you'll get more than one result. Will %isvalue return a stringlist in that case?

Posted: Fri Oct 12, 2007 3:03 am

Also, the %replace example you gave is very much not working, Zugg. I'd rather %expanddb or %replace worked, rather than making a new function.

Also, Seb, it seems weird that you want to use %dbitems rather than %dbkeys for your friend list, Seb. How would it work?

#additem Friends.Citymates %1

You wouldn't want the key in that situation. Unless you mean something like:

#additem Friends.Harry {List|of|Harry's|Alts}, in which case you could just have the name "Harry" in the value list as well.

Wizard Joined: 14 Aug 2004 Posts: 1269

Posted: Fri Oct 12, 2007 12:53 pm

Eh, a few bytes per person isn't going to make much of a difference. If you already have your dbvar set up without the key in the value list, it's easily added with #loopdb anyway.

Posted: Fri Oct 12, 2007 5:42 pm

Posted: Fri Oct 12, 2007 5:54 pm

Sorry, yes, I meant index. My point remains the same:

#addkey Names Friends Zugg
#addkey Names CityMates Zugg
#show %isvalue(@Names,"Zugg")

Will it return both key indices?

And I was talking about %replace in trigger patterns. I didn't realise that functions like that weren't allowed - I guess adding %dbitems won't help with Seb's problem, then, because you'll still have to use a variable to store the %dbitems stringlist in.

Posted: Fri Oct 12, 2007 6:24 pm

Wizard Joined: 11 Jul 2002 Posts: 1265 Location: USA

Hey guys... I don't suppose any of you have gone back and looked at the thread I answered that started this whole conversation?
I *did* find a better way to solve that particular problem.

Also keep in mind that I tend to think outside the box/rules. This sometimes causes me to miss the obvious as I did in this problem to begin with.

#function addName {#addkey spys %1 %2;names=%replace(@spys,"=","|")}
#function delName {#delkey spys %1 %2;names=%replace(@spys,"=","|")}
#regex spytrig {\b@names\b} {Zugg's nice new functions do away with most of the nonsense I had here before}