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

I love the new Lua ability to use hash tables in variables. What is a hash table? Let me explain.

Most of us know about using database variables to store a key value pair like so.

#addkey variable key value

Then we can retrieve it using one of the following.

@variable.key or %db(@variable,key)

And we can set them using the following.variable.key=value or by just using #addkey again to recreate the value

#addkey variable key newvalue.
Wonderful, but what if you wanted to store more than a single value in a single key?
It could be done but it was usually messy and it normally consisted of using %word or %item to separate out a string.

An example of this is the following from the Generic queue thread.

Skill Name=Priority Number, Balance Requirements [string List], Uses these balances [and thus removes them] [string list], Gives these balances [string list], Keep this item as a priority until it is confirmed [0 or 1] <-<< This last one is not fully implemented and I suggest that you leave it as 0

Example
Vitality=P-90,R-A|e|G|N|S|V|x,U-e|V,G-,C-0

Skill Name: Vitality
Priority Number: 90
Balance Requirements: A|e|G|N|S|V|x
Uses these balances: e|V
Gives these Balances: None
Keep on list:0

Checking and changing all of these values is a real pain. Not to mention understanding them when you look at the code.

Fang suggested using hash tables instead.

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

Please note that the < is converted to a < when placed within code tags. And that makes copying and pasting the xml not work. If you want to try out this function I added it to the package library.

Edit: Taz fixed the above code block. But I have updated the code several times since the above post. For the latest, [and faster] code download the package from the library.

Posted: Mon Jan 07, 2008 3:26 am

Some things that struck me, large and small, while reading your code:

Line 4, you use "do return end" which is only needed if the return doesn't immediately preceed an "end". Since it does in this case, all you need is a return. Line 12, you reference a variable vart that you haven't defined. Your structure from lines 18-26 could probably be simplified because by this point you definitely have at least a key and a value. I was thinking something like:

Enchanter Joined: 05 Mar 2003 Posts: 593 Location: Canada

The reason why the hashes need 2 or more keys is this:
If in a record-variable you have the key-value pair
Key:girl
Value:hair=blond
The algorithm that is used to translate this to a lua value has no way of knowing if the value represents a string literal or an embeded record-variable which should be translated as a table
with the key-value pair
Key:girl
Value:hair=blond|wears=dress
It assumes that this is an embedded record-variable and translates this to a hash
This would be a problem if you wanted the value of the last example to be a string literal.

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

Thanks Fang, ok so I went over the issues you mentioned.

1. do return end line 4.
--Cmud throws a Lua error if I remove the end.

2. Undeclared variable check at line 12.
--Declared it. You are correct it was an oversight on my part. This should speed up the function.

3. Lines 18-26
--Made the change. Thanks. This should speed up the function.

4. Lines 29-31
--I am checking to see if the current Level of the hash is a lua table.
--Before I was setting the Zscript variable to a database type if it was not one. And creating the variable if it does not exist.
--If it is already a table and I set it as one I will delete any of the nested contents.
--If it does not exist or it is some other type than a table Cmud throws a Lua error.

5. Loadstring and functions.
--Had a heck of a time with the functions but now I only have two functions that I use repeatedly instead of building and trashing new ones.

Apprentice Joined: 08 Dec 2005 Posts: 108

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

Actually... I just looked and it is NOT still in the library Exclamation

Unfortunately I don't have a clean copy of it that I can upload tonight. I've been monkeying with it and I don't have time to fix it. I have an old copy and one that doesn't work. I had the latest working copy online Or thought I did. Shocked

The one that is posted above does work so I guess use it until I get the new one back into the library.

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

The latest version is now in the Library for download. Sorry for the trouble.

MAN is the library a pain to administer!

So for a nine year old boy name John with brown hair who is wearing size 10 blue trousers, a size small red shirt, and size six black boots you could do the following.

#call @HashSet(people,John,sex,male)
#call @HashSet(people,John,age,9)
#call @HashSet(people,John,hair,brown)

#show @people.John.sex
#show @people.John.age
#show @people.John.hair

#call @HashSet(people,John,clothing,torso,item,shirt)
#call @HashSet(people,John,clothing,torso,color,red)
#call @HashSet(people,John,clothing,torso,size,small)

#show @people.John.clothing.torso.item
#show @people.John.clothing.torso.color
#show @people.John.clothing.torso.size

#call @HashSet(people,John,clothing,legs,item,trousers)
#call @HashSet(people,John,clothing,legs,color,blue)
#call @HashSet(people,John,clothing,legs,size,10)

#show @people.John.clothing.legs.item
#show @people.John.clothing.legs.color
#show @people.John.clothing.legs.size

#call @HashSet(people,John,clothing,feet,item,boots)
#call @HashSet(people,John,clothing,feet,color,black)
#call @HashSet(people,John,clothing,feet,size,6)

#show @people.John.clothing.feet.item
#show @people.John.clothing.feet.color
#show @people.John.clothing.feet.size

Posted: Fri Feb 01, 2008 7:18 pm

Posted: Sat Feb 02, 2008 2:52 am

Calling This From Within An Event With A Named Param Breaks It. LUA reports The Parent Events Params As The Functions Params

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

Yes there is a way to do this indirectly but I wanted to keep it as simple as possible.

If you create a string list in your event and then alter this function to accept your string list instead of using params and param(1) you can use it with events.

Wizard Joined: 17 Jun 2006 Posts: 1201

I love this.

However, I am not sure how to get the right values to display for what I want to do.

I am using this to store all my guild stocks. I just use a regular database for totals, but the problem is you might have multiple commodity stores with different quantities. So I want to display STOCKLOCATIONS and have it loop through the StockLocation database and display the commodity, location, and quantity in that location. The value changes though so I am not sure how to display it correctly.

Here is the trigger to start recording:

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

Because you know the structure of the table you can create the alias to display it based on that structure.

#loopdb @StockLocations.copper.location {#show %val %key}

Gives you most of the information that you need and should point you in the right direction.

It is late and I'm running on batteries so if you need more help post again and I might have time later to write up the whole alias.

Wizard Joined: 17 Jun 2006 Posts: 1201

This sort of worked except it displayed it like this...

location table
49 Inside a room A
2 Inside a room B
location table
10 Inside a room A
location table
20 Inside a room A
5 Inside a room B

I just gagged the "location table" and displayed %i first then looped the db with your code above and got what I wanted.

Now it shows:

Copper
10 Inside a room A
5 Inside a room B
Tin
12 Inside a room A
1 Inside a room B

Thanks.