Help talk:Extension:ParserFunctions/2014-2020

replacing #ifexist with #dpl
The behaviour of #ifexist can be reproduced with DPL using the following syntax:
 *  

which is equivalent to:
 *  

DPL has the advantage that it does not create a link between the target page (page title) and the page containing the query. Using #ifexist would cause your page to be listed in Special:WhatLinksHere/page_title.

—Capmo (talk) 06:42, 18 August 2012 (UTC)


 * #ifexist is faster. Avoid calling DPL wherever you can. --Subfader (talk) 13:23, 19 August 2012 (UTC)


 * DPL makes direct queries to the database, what can be faster than this? And there must be a reason for #ifexist to be labeled as an "expensive parser function". The wiki I administer uses DPL extensively for all sorts of things, and we don't feel any perceivable degradation in server performance. Capmo (talk) 21:53, 21 August 2012 (UTC)


 * Initializing DPL on page load takes longer than ParserFunctions. "#ifexist to be labeled as an "expensive parser function"" that's because the DB load gets expensive on calling it X times, but the same counts for calling DPL X times on a page... --Subfader (talk) 11:50, 22 August 2012 (UTC)

If A or B or C (resolved)
I am trying to use the if statement to test for multiple different values.

For example: would display "YES" if any of the three (a,b,c) variables were defined. If, and only if, all 3 were NOT defined, it would display "NO".

I simply cannot get this to work! Any help would be most appreciated.

--Zackmann08 (talk) 01:09, 10 September 2012 (UTC)


 * Try it like this . If one of the parameters has a value it will display YES, only when non of the parameters has a value it will display NO. In this way you can make any combination you want and make it as complicated as you want. --Jongfeli (talk) 09:03, 10 September 2012 (UTC)


 * The issue is that I am attempting to use this to do something much more complex than just displaying "YES" and "NO". I am using it to create a rather large table. Is there no way to do "If A or B or C"? --Zackmann08 (talk) 13:50, 10 September 2012 (UTC)


 * If I understand you correctly you would like to fill a (calculated) column in a table and the value depends on other values in the same row? I tried this in combination with Extension:External Data but  does not work because it probably always gets a value back from the Query. It does not matter if there is a database NULL in the table or an empty string. Just to see if it can work I tried   (see example below) but it only works on the first row it displays, if in the first row a = 1 it will display Yes and it will repeat the result on the rest of the rows even if a is not 1.

{| class = "wikitable" ! Column 1 ! Column 2 ! Column 3 ! Test
 * Maybe I am doing something wrong but it seems that in combination with External Data the ParserFunctions does not handle each row individually. --Jongfeli (talk) 15:19, 10 September 2012 (UTC)


 * This is part of an infobox. I am trying to copy the technique used on wikipedia (For example: http://en.wikipedia.org/w/index.php?title=Template:Infobox_weapon&action=edit)
 * In the example below, the heading for the "Service History" only displays if "service", "used_by" or "wars" is defined. For some reason, this exact syntax is not working for me.








 * --Zackmann08 (talk) 15:47, 10 September 2012 (UTC)


 * So its now working. Not sure what i was doing wrong... Oh well! --Zackmann08 (talk) 16:26, 10 September 2012 (UTC)

If number check (resolved)
I am attempting to write an error checking function that checks to see whether a user has supplied either a year (####) or the word "Present". (This is for an infobox for a vehicle. I want to display the production years.) I am 99% of the way there with the following:

The issue that I am having is that if a valid date is supplied, then the expression evaluates and is displayed. Is there an easy way to suppress that expression? I seem to remember seeing a "span display=none" type thing somewhere...

Any advice will be greatly appreciated.

--Zackmann08 (talk) 14:35, 19 September 2012 (UTC)


 * I love solving my own problems. :-) was my solution. --Zackmann08 (talk) 14:40, 19 September 2012 (UTC)


 * I also had a similar question because the parser functions give script errors in some cases. I had do this. --Rical (talk) 22:50, 19 September 2012 (UTC)

How to use tag function within parser function?
I'm trying to build an if-clause that automatically inserts == References ==  character or possibly a tag inside a function where tags aren't allowed. However, even when I remove all instances of the  character from the template (by eliminating the comments, the   tags, and the   tags), the error message persists.

Here is the text of the template:

[removed]

Any idea what the problem is and/or how I can correct it? Thanks! ~ Michael Chidester (Contact) 15:07, 22 March 2013 (UTC)

Solution
Ultimately I determined that this was a DPL conflict, possibly due to the  function refusing to parse the standard output format of DPL. To help anyone having this problem in the future, here is my modified code, changing out the deprecated string functions for their replacements and modifying the DPL output to produce a regular string rather than a link:

The next document number is 

Cheers. ~ Michael Chidester (Contact) 15:40, 26 March 2013 (UTC)

See also Scribunto ?
Now, we have modules in scribunto/Lua and the syntax to call them is " {{#invoke| ". Then users will try to search them here and we could add Extension:Scribunto to "See also" paragraph ? --Rical (talk) 18:13, 11 May 2013 (UTC)
 * I think you should create a section Extension:Scribunto/Lua reference manual on the extension page, since that should bring this section to the top of the search results when people search "invoke". --Theaitetos (talk) 22:11, 12 May 2013 (UTC)

How can we do a sum ?
Hello ! Is there a function to do the sum of A+B+C+D+E ? Historymating (talk) 11:42, 8 June 2013 (UTC)


 * expr can calculate sums. But it's not possible for any function to process things, that are not in the input area of the function itself. --Theaitetos (talk) 13:58, 28 June 2013 (UTC)

Unwanted whitespace in article from #switch
I'm using a template whose entirety is just a switch statement to transclude one of two possible subtemplates. However, ParserFunctions seems to be adding an extra line of whitespace before the result of the switch statement when I use it this way. Is there a way to remove this whitespace?--Idran (talk) 01:46, 28 June 2013 (UTC)


 * Hello Idran. You should first check if the template adds the white space (line break). If you want to be strict on what gets transcluded via the template make sure you put everything that needs to be transcluded between  tags. Below an example.

Any Template documentation

 * Bla bla 1
 * Bla bla 2
 * Bla bla 3


 * If you don't do that you could easily transclude a line break to a page. --Jongfeli (talk) 08:34, 28 June 2013 (UTC)


 * I disagree with Jongfeli. en:Help:Transclusion has an informative section on how transclusion and the various include tags work.  Idran if you could post the markup from your template here, I would be happy to help you make it work as you expect.  I'm thinking the #switch might not be needed if there are only two outcomes and maybe an #ifeq would work better. Technical 13 (talk) 12:13, 28 June 2013 (UTC)


 * Actually while I was copying the code of the templates here, I noticed exactly what the problem was; I had an includeonly section in the subtemplates that I hadn't realized was adding an unwanted linebreak, and I didn't notice it because I was focusing my attention on the template itself. Apologies for the unnecessary responses!--66.254.228.224 19:26, 28 June 2013 (UTC)


 * Whoops, didn't notice I wasn't logged in; that was me above.--Idran (talk) 19:59, 28 June 2013 (UTC)

Hebrew calendar (Jewish calendar) date as date/time object
Is there a way to enter a Hebrew calendar date as a date/time object in the #time: function? In other words, I know how to get a Hebrew calendar date out by entering a Gregorian date/time object in the function. Can I do it the other way around? Thanks. StevenJ81 (talk) 01:34, 24 July 2013 (UTC)

HTML and Parser functions
I have tried to use Parser functions with HTML(More accurately CSS), but there is some conflict made by the ">" operator. What can I do in order to solve the problem? Thanks. 219.78.217.178 22:40, 9 August 2013 (UTC)
 * Without you showing us the code in question that you are getting errors for, the first suggestion I may offer is to use &amp;lt; and &amp;gt; to achieve &lt; and &gt; respectively. Technical 13 (talk) 23:37, 9 August 2013 (UTC)


 * For example, using a style tag...
 *  180 | 180 | }}$}}deg);'>

The > makes the tag closed and caused errors, so what should I do? 219.78.217.178 10:00, 14 August 2013 (UTC)