lua function call overhead

Your help pointing to ways to improve is welcome. It receives a *lua.LState and returns an integer. The #invoke speed in March 2013 has been about 180/second, compared to short templates running 350-600 per second, or parser functions >750/second, or character-insertion templates running 2,400/second. I would use them again if needed. for example, make this work without copying the args to a new table? I can acquire arguments using the frame.args object passed to a script using an iterator function: But this does not seem to work for a library such as mw.site. Its much easier to test if something is non-nil or has a specific type/fields in Lua than in C++. For example, I might want to process the posts on a talk page, and add some extra formatting. Thanks! Although Lua can still process the 6,000 parameters, to compare choices, within "0.02" Lua seconds, the load time of the #invoke interface is 27 seconds. The function signature must match what you passed in. If this behavior is not suitable for your usecase, a custom handler function for resolving conflicting functions can be used by passing a function as an optional second argument. The system compares actual template output with fixed text, and is only suitable for templates and results that are reasonably short because each template and its expected result have to be in one line. It has a GNU Make build, so building it is easy. For example, return {84 = 132}, or return {'84' = 132}, or return {0 = 00}, give errors demanding a } near the =. To get the perf bit Youre unlikely to run into performance issues, unless youre making a AA/AAA game or a complex simulation program. Similarly to the previous advice, when defining classes (e.g. Think of Lua scripts as functions - you can call them with require or do_file and they can return variables. Johnuniq (talk) 09:37, 7 October 2013 (UTC). The advantages are a) edits to Redirect to add irrelevant features don't lead to massive queue usage, b) Redirect doesn't have to be protected, and c) in case a required module isn't protected, you don't get confused and fool around with a module you think is in limited use only to find out that you've created a huge server load. However, after writing up Module:Hex, which hex dumps the contents of strings, I was looking at the talk page when I noticed that the hex-dump of the contents of a strip marker (the example with UNIQ QINU) are changing every single time I hit the Talk tab or browser reload button to reload the page, even when I'm completely logged out with scripts disabled! Ginsuloft (talk) 13:39, 30 October 2013 (UTC), currently, in Module:Historical populations, I am using a somewhat convoluted method to access 'formatnum' which involves passing 'frame' and using 'callParserFunction'. The simplest language I know. It doesnt have many gotchas. powered by Hugo :P Anyway, I have taken that idea and added some parameter checking and some documentation, and called it Module:User:Mr. Stradivarius/PrefixIndex. Because the property from Wikidata is not updated by mw.message, I decided to try it on one of those pesky Special: pages that abolish caching. I'd like to include some of the functionality of module:Page in my module, without having to reinvent the wheel. If you notice that your C++ function has a huge overhead because of Lua calls, consider using this pattern: If you dont use local to define/init a variable, it becomes a global by default. Functions are the main mechanism for abstraction of statements Given that each {{#ifexist:}} is an expensive parser function (EPF), these templates can consume an excessive number of EPFs. The first question, of course, is whether we should require() at all. or compute and return values. I did not see any mention of this in the tutorial.--greenrd (talk) 10:04, 19 October 2013 (UTC), I've started up a new discussion about this at Wikipedia talk:Lua style guide#CodeEditor switched to tabs. -- Don't need the "%. If a conflict can not be resolved in a satisfactory manner, the function should throw an error to signify this; returning false or nil will result in that value being written to the key. with nil arguments removed. However, in the example where SomeClass is returned as a local variable, you wont need to do this - if you just load the script.lua, it would execute some_class.lua when you call require (it would only do this if another script didnt call it, otherwise it would return a cached SomeClass variable). Thanks. Unfortunately, I have not yet been able to think of a way to mix this logic to get what I want, namely a way to control whether results are updated daily or weekly, etc., because I haven't thought of a way by which the logic of whether time has passed will always be evaluated but the logic of the page content will not be, unless the time has come, at which point the caching should be updated on that page. --Rotpunkt (talk) 12:35, 1 May 2013 (UTC), Hello, I'm wondering if there is currently a module that counts elements on a page. My initial thought is that having a module named after a single string function may be a bit extravagant, so perhaps it would be better grouped with other similar functions, if those exist somewhere. The reference manual for Lua 5.4s C API is here: https://www.lua.org/manual/5.4/manual.html#4, Github repo: https://github.com/ThePhD/sol2. Putting the following into the debug window gives the values shown: I don't need the functionI'm just asking if it has a bug. DePiep (talk) 23:55, 21 May 2015 (UTC). WebLua Functions - A function is a group of statements that together perform a task. Isnt it great? Servicing Northern California For Over 25 Years, Select The Service Your Interested InDocument ShreddingRecords ManagementPortable StorageMoving ServicesSelf StorageOffice MovingMoving Supplies. Its neat. It relies on Module:Sandbox/QuimGil/Flagicon, which provides the logics, and Module:Sandbox/QuimGil/FlagTranslations, where the flags data is stored. Lua is written in ANSI C, so it can compile almost everywhere. If you think that your game became slow because of Lua code, profile first before rewriting it in C++. I'm thinking by this point that it would be better to just develop an explicit tool to control caching, and some mechanisms (if they don't already exist) to audit what pages are not cached and identifying the worst reloaders) Wnt (talk) 15:48, 13 January 2014 (UTC). You can write entire games in Lua without ever touching C/C++. ), You dont need a specialized IDE or tools to write Lua comfortably. Functions used by a Lua program can be defined both in Lua and Requires all Lua files in a given directory. I get an error message when I use it. -- Gets numbers for row1, row2, etc. NeoVim, which uses Lua scripts for user script code. Then, see if you really need to move this code (or parts of it) to C++. You can easily print table contents with it: For example, Id recommend to avoid SDL/glfw/SFML bindings and writing them manually for the stuff you need. Makyen, does that look something like what you wanted? d Use Git or checkout with SVN using the web URL. Dont forget that you can do this: Now, when you load/execute this script, you will only get one function as the result: All the internal script state will be hidden and non-modifable and wont overwrite any global state in your current Lua state, which is great. Throughout the post L will denote a pointer to lua.LState. Iterative multi-file loader, used to load all Lua modules in a directory and return them as one table. This concept might be extended to support more than one memory location: Hi, is there a way to instruct string.format to not produce trailing zeros with decimal notation? For instance, consider the following function, to increment a global counter. This function has 1 as its default argument; that is, the call incCount (), without arguments, increments count by one. When you call incCount () , Lua first initializes n with nil ; the or results in its second operand; and as a result Lua assigns a default 1 to n . There is no reason to do it for functions which are already now i wanted to translate Category:Pages with script errors in bn language. So the idea is the next one: But lua has a specific way to treat weblink and it is right now impossible to use a web address as a string. :) Wnt (talk) 02:58, 6 January 2014 (UTC). And finally, see what LVE and PICO-8 do. The docs are fantastic too. Sorry if this was discussed before, but I did not find relevant links in a couple of minutes. --Iantresman (talk) 13:14, 8 December 2013 (UTC). It stays global and doesnt get collected by a GC until it has been set to nil. I would welcome comments, and if people think the scheme is OK, please consider rating your modules Wnt (talk) 23:31, 16 April 2013 (UTC), I have opened a discussion here: en:Module_talk:String#Replication on other wikis. --Iantresman (talk) 18:29, 7 December 2013 (UTC), I used to be an above average template editor, making significant contributions to even such intricate template as Ambox and Fix. Automatic insertion of the green 'chrome' of our template documentation. This code is OK (calling C++ from Lua is cheap): This code is not that good (calling Lua from C++ is slow): Profile first. I am trying to create a weblink by concatenating 2 strings and by avoiding the display of the full link in an infobox. 1 Answer Sorted by: 3 I would generally recommend to avoid making high volume calls into Lua. Of course, you can check for this files existence and handle errors appropriately (e.g. Our areas of expertise include Commercial Moving Services, Warehousing, Document Shredding and Storage Solutions. The LTable type can be used for emulating namespaces and classes. a function definition has a conventional syntax; Its a good starting point for making your own CMake build for Lua, though (or if you use older versions of Lua, they work well). Should I return a sequence of hundreds of strings relying on Scribunto in concatenating it? For variety, and to match the fact that if you know what values you are dealing with you might have some "ifthenelse" statements to handle them, I did the format slightly differently. Right now I'm putting ratings on the documentation subpages, which I think is what someone suggested before at one point for categories. For example like: frame.args.row1. I've been trying to get to grips with the concept of frames, and I think I'm almost there. The message from MediaWiki:Movepagetext-noredirectfixer should warn about this, perhaps a warning like MediaWiki:Moveuserpage-warning. The value of any of these keys will never be. Older versions of Lua created empty tables with some pre-all ocated slots (four, if I Does mw.ustring.byteoffset work correctly with negative offsets? It may sound like asking to be babysat or spoon-fed, but I'm totally stuck. What I'm trying to do is much more complicated, see Module:Convert/makeunits, but is the same issue. *, I'd like to find out which mw.site library options are available, and print their value, without having to specify each one individually, ie. Affects Lua, templates & parser functions: Again, the time-delay overhead, to pass thousands of parameters, not only affects the Lua #invoke interface, it extends the same exponential time-delay slowdown in passing parameters to templates as well as "|x=" branch-choices in a #switch function (which also runs 27 seconds to process 6,000 branches). You can easily create a Lua state which wont have any functions from the standard library (I/O, coroutines, tables etc. Eg: {{example |row1 = {{template2|height=52}} }}, In the above exaple we can get row1 as frame.args.row1 but is it possible to get height from row1. Does this apply if you are accessing the module from another Lua module, and not directly from a wiki page? Even if you do, with LuaJIT youll be able to achieve C/C++ level performance. That would only apply to your contributions though, not to later modifications made by other editors. Frietjes (talk) 16:17, 30 October 2013 (UTC). "factorial: argument must be a number >= 0", -- likely something like 1=foo=bar, we need to do it as a named arg. For example, suppose that you have C++ code like this: Your engine will crash on startup if init.lua is not found when your game starts (or contains errors). In short, if your coroutine gets GCed and you hold the reference to this local variable as a sol::object on the C++ side, it wont prevent the variable from getting GCed by Lua and your program crashing because of that. Hex (? There are some practical functions to convert and check lua.LValue objects. In Lua, all arrays are 1-indexed, however t[0] is still valid but that would result in the lenght of the array to be off-by-one. Given an instance myqobject of this class, a Lua program can emit signal mysignal as follows Is a module supposed to do something clever in order to output tags? This is a matter of implementation of the compiler or runtime (and its options) and cannot be said with any certainty. If you notice that your C++ function has a huge overhead because of Lua calls, consider using this pattern: // in C++ sol::table t = lua.create_table (); for (int i = 0; i < 1000; i++) { // do stuff in C++, push data to Lua table occasionally } luaFunc (t); -- in Lua function someFunc (t) for k,v in pairs (t) do -- do stuff end end 5. Everyone took really good care of our things. Your opinions on the matter are welcome; please participate in the discussion by adding your comments at Wikipedia:Miscellany for deletion/Wikipedia:Lua/To do and please be sure to sign your comments with four tildes (~~~~). It can do everything youd ever want from Lua and even more. Lua adjusts the number of arguments to the number of parameters, The typecheck function could also store away the type info for later introspection. Often the linked module contains bells and whistles that aren't really necessary; why not bring it into the module and slim it down? is there a better way to do this? Its stable. Best Mr. Stradivarius talk 10:42, 27 March 2013 (UTC), You've got it pretty much right. Wnt (talk) 23:14, 21 March 2013 (UTC), I have run many timing tests, to compare using shell templates which contain #invoke versus direct use of {#invoke:}, and for tiny templates, such as string-handling functions, the template versions often ran upto 50% slower than direct #invoke of each tiny Lua function. Its minimalistic, but requires a lot of boilerplate and manual error-checking. The redis instance enables the script to interact with the Redis server that's running You signed in with another tab or window. Now, with this new LUA language, template editing is becoming more and more the domain of technicians. its hard to know if what youre passing to Lua will be copied or passed by a reference). I used their packing and moving service the first time and the second time I packed everything and they moved it. They both open a file, read one line, and close it, or do nothing if there was some error opening the file. Learn more. If needed, custom metadata can safely be written to the metadata table; it is unique for each key and will persist for the duration of the load() call. L.DoString runs the Lua code in the VM. Thank you. Page contents not supported in other languages. You couldn't keep track of your old experiments, and my experience is that yes, I. Using the L.CheckTypes function equate to checking the type manually and then calling L.TypeError(n int, message string) if there is an error. If you create a local object inside the coroutine and store the reference to it in C++. You can download the latest release manually and include it in your project, or you can install it in your project directory through Luvit's package manager Lit, using the install command. Then, executing script.lua would resullt in an error: SomeClass is nil. (what is sometimes called procedure Formula: is to create and maintain customer confidence with our services and communication. Snipre (talk) 07:52, 31 October 2013 (UTC), Is there a LUA method for '#ifexist' that doesn't generate false incoming links? mw:Extension:Scribunto/Lua reference manual#mw.title.makeTitle, en:Module_talk:String#Replication on other wikis, http://commons.wikimedia.org/wiki/Commons:Lua/Modules, Help talk:Template#Counting items in numbered list, WT:WikiProject Templates#Counting items in numbered list, Wikipedia:Help desk#Counting items in numbered list, betawiki:MediaWiki:Scribunto-common-error-category/bn, mediawikiwiki: Extension:Scribunto/Lua reference manual #table.concat, Bug 50329 - We need a common repository for Scribunto modules and templates, Template:Year in other calendars/testcases, Module talk:Sandbox/Johnuniq/grosstonnage, Wikipedia talk:Lua style guide#CodeEditor switched to tabs, submit code to implement a ulimit-like mechanism on Windows, Special:WhatLinksHere/3000 United States Census, mw:Extension:Scribunto/Lua_reference_manual#Returning_text, Module:Sandbox/iantresman/sandbox/archive/mw.recursive, User:Iantresman/sandbox/archive/mw.recursive, Special:PrefixIndex/User:Mr. Stradivarius, Help:Lua_for_beginners#Initializing_a_table, updating some Lua modules can cause 7 million pages to be reformatted, Template_talk:Convert#Deploying updates now 18,000x slower, Wikipedia:Miscellany for deletion/Wikipedia:Lua/To do, https://en.wikipedia.org/w/index.php?title=Wikipedia_talk:Lua/Archive_1&oldid=1137418039, Creative Commons Attribution-ShareAlike License 3.0. Casey Moving Systems is family owned and has been servicing Northern California for over 25 years. Incnis Mrsi (talk) 11:59, 2 July 2013 (UTC), Hi, your feedback is welcome at Bug 50329 - We need a common repository for Scribunto modules and templates. Maybe. The compiler might decide "hey, this function is only called a few times, and I'm supposed to optimize for speed, so I'll just inline this f If an argument to a function can be of more then one type the L.CheckTypes(n int, types LValueType) function can be used to check and yield an error to the user. Text formatting (bold, italics) breaks when the ''/''' tags are not closed for each argument. Hence, passing 2,000 parameters runs 3 seconds, 4,000 parameters runs 13 seconds, or 6,000 parameters run 27 seconds. I think that this is less effective than it could be, however. Page content can be retrieved with the getContent () method of the title object. If you used classes as globals (which Ive seen in many tutorials and real code), you might have a script like this: Suppose that you didnt execute some_class.lua first (which defines a global SomeClass). I'm currently using the following function to get template arguments. Ive used LuaDists CMake build scripts for Lua for many years, but LuaDist authors have stopped supporting newer Lua versions. I don't think it was really a active decision. The process was smooth and easy. Exposing Go functions to Lua is essential to create custom a custom API. In the first case, we use a function call as a statement; To get automatic errors the L.Check(n int) family of functions can be used; They throw a Lua error if the type check fails. How do I fix this? Wnt (talk) 15:52, 22 January 2014 (UTC), Wikipedia:Lua/To do, a page you substantially contributed to, has been nominated for deletion. How you divide up your code among different To learn Lua, read Programming in Lua by Roberto Ierusalimschy. I tried to start learning Lua and immediately hit the wall after the "hello, world" part and all I got afterward are "script error". Perhaps li in a list or tr in a table? The approach of Module:Sandbox - having every user put scripts into a common receptacle - seems unworkable. I've created a new request page for Lua scripts at Wikipedia:Lua requests. For example (C++ functions have cpp postfix): Ask yourself: do all these functions need to be in C++? That's a bit of boilerplate code that I've been using in all the modules I write. My own modules populate only the pre-alpha and alpha categories, but there are some here which I know have reached the other levels. The resty command itself has a startup and exiting overhead. with nil arguments removed. Is it a good idea to deviate from the template standard of calling pages with testcases, tests for the module namespace? Extra arguments are thrown away; Now you dont need to ship this init.lua with your binary and life becomes easier. You can call a function with a number of arguments different from Still, there are a lot of options available maybe someone can think of something? 3 These variables are called the formal parameters of the function. The formal parameters behave like other local variables inside the function and are created upon entry into the function and destroyed upon exit. While creating a Lua function, you give a definition of what the function has to do. Then we call the function with lua_call (). Thank you!--QuimGil (talk) 07:52, 21 June 2013 (UTC). I wonder if there's any actually helpful tutorial for those already familiar with Wikisyntax but without other computer language experience like Lua or C. The tutorials I found usually begin with a simple code to tell you to copy-and-paste (hello, world) then look at the outcome. The simplest way to time some Lua code is to use the time command with the resty command. At the moment, we have three patterns in naming a module sandbox page: I suggest that is one too much. It is also possible to make the function a parameter if it comes from a defined list of choices - just load up your data and set a loop that p[xyz] = function(frame) return p.main(frame, xyz) end. The fact that even an IP user may edit the module namespace suggests that it must be really stable and secure. Many 3rd party Lua libraries usually work with Lua 5.2/5.3/5.4. The downside is it will incur a small performance impact every time a new page of callframes is allocated. Any suggestion on how to receive this parameter template as a table rather than a substituted string? These functions does not throw errors, but will return Go default values if conversion is not possible. So tonight I put together Module:Unsubst, which can be used to do the same thing without all the limitations of {{unsubst}}. This commit does not belong to any branch on this repository, and may belong to a fork outside of the repository. lua.LVAsString(v LValue) - Converts LString and LNumber to string. / Each layer of "shell templates" (to #invoke a Lua function) also increases the expansion depth by about +2 levels of the 41-level limit (shows "41/40"). Providing global relocations solutions, storage and warehousing platforms and destruction plans. after imported i find error in article with this Category:Pages with script errors. There are a number of To(n int) functions available. -DePiep (talk) 23:30, 19 July 2013 (UTC), Do Module:WikiLink and voy:ru::Wikilinks effectively aim to do the same thing? {\displaystyle d=3^{(n/2000)}.} See discussion at Village Pump (policy)#Protection and management of scripts?. You can even create small domain specific languages thanks to Luas syntax sugar. Mr. Stradivarius talk 14:16, 4 November 2013 (UTC). mw.site.currentVersion, mw.site.scriptPath, etc etc. Calling Lua code is done through L.CallByParam, which takes a parameters object, P, and arguments as variadic parameters. On each conflict, this function will be passed the conflicted key, the current value that load() is attempting to save, the value that is currently stored in the conflicted key, and a table of metadata consisting of the following: Please note that these keys are created and updated automatically by load() and should not be altered manually. Johnuniq (talk) 06:53, 11 October 2013 (UTC), Doesn't Wikipedia's version of Lua allow the GetURL function (or equivalent)? I also worked on a fork of LuaJIT professionally and described my experiences here - this experience made me learn a lot about LuaJIT and how vanilla Lua works (and how it can be used in production for servers with a very high QPS). Note: Lua isnt zero-indexed, so the first function argument is fetched with L.ToInt(1), second argument with L.ToInt(2). {{. Installation You can download the latest release manually and include This bytecode is converted into LLVM IR and then fed into Deegen, which can transform the functions to do tail calls correctly, use the GHC calling conventions, and a Hence, for Lua, the alternative is to pass fewer parameters, but as strings of choices delimited by separator characters within each string. The parser seems to reject any effort to initialize a table in the return statement if one of the indexes is, or could be, interpreted as a number. The general method that has been used is to assume a format for the page archive name and then test for the existence of all such possible pages using {{#ifexist:}}. The parameters object takes three important parameters: The following code defines a concat function in Lua. Wnt (talk) 15:56, 6 January 2014 (UTC). Johnuniq (talk) 22:58, 10 January 2014 (UTC). The syntax of the template sends another template as parameter. That overhead might be removed if we made save/restore a built-in operation in Lua. With a clear upsream in a central place like mediawiki.org then en.wiki and other Wikimedia projects could work better on local support and whatever is specific to their communities. : Overusing them makes code harder to understand because now you need to make sure that the object youre are pointing to doesnt change unexpectedly. Please let me know your thoughts over at Template talk:Pagetype#Module:Pagetype. Technical 13 (talk) 12:12, 9 May 2013 (UTC). (and object-oriented programming) in more detail. Clearly it's worth thinking about ways to reduce this impact as much as possible. To iterate a table, instead use for k=1, #tbl do local v = tbl [k]; It does exactly the same without the function call overhead (pairs actually returns another function which is then called for For example, Module:Navbar contains the code: In what case would frame not be equal to mw.getCurrentFrame()? I would generally recommend to avoid making high volume calls into Lua. OUR MISSION. What is the equivalent of {{fullurl:page name}}? I was wondering if there is a way to improve the performance. It's just that a central repository would be so beneficial for everybody (en.wiki devs/editors included) and en.wiki can't really be (in my honest and personal opinion) that place. if u can help me)I imported Module:Citation, Module:Citation/CS1/Configuration, Module:Citation/CS1 in bn.wikipedia. However, I found that returning mw.message.newRawMessage("{{User:Wnt/Templates/Sandbox2}}"):parse() produces a timestamp that never changes when the page invoking the module is reloaded, because the page transcluded is not checked at all. Currently, there are a reasonable number of templates that try to determine if any of a set of pages exist in order to provide links to those pages. Many Git commands accept both tag and branch names, so creating this branch may cause unexpected behavior. You can call it with LuaJITs FFI, see the tutorial here. The NewPP parser hits the huge delays when passing 6,000 parameters whether to Lua, or to a template, or to a #switch parser function of 6,000 "|x=" branches. I was just trying to return those hex tables via loadData and seem to have run into a nasty surprise. My new test module Module:Sandbox/iantresman/sandbox/archive/mw.recursive prints out "frame.args" arguments passed to it, but is not recursively printing "mw.site" library functions/table when accessed from User:Iantresman/sandbox/archive/mw.recursive. via middleclass library), dont do it like this: and then, when you want to create an instance of this class, you do this: Why do it like this? 1 time resty -e 'ngx.re.find ("hello, world. I ran some local tests and it seems pretty easy to crash it, but then again I'm running it in an unstable environment anyway so it may not reflect how things work here on Wikipedia. Mr. Stradivarius talk 12:54, 10 July 2013 (UTC), We have {{WikiProject Lua/header}} that does the header tabs (I started). This will make your life easier, because you would be able to write less binding code and be able to stay inside Lua code as much as possible. its number of parameters. may be relevant to this problem. However, the basic API is quite simple, and the advanced features deserves its own post. For instance, if we have a function like. Its easy to integrate Lua scripts into C/C++ projects. -- The parentheses remove the "number of changes" returned by gsub. there is no difference between functions defined While still largely relevant for later versions, there are some differences.The fourth edition targets Lua 5.3 and is available at Amazon and other bookstores.By buying the book, you also help to support the Lua project. If you'd like to make a request, please do that too! WebLua scripts have the same capability with calling MMF events. (In the case of Module:Redirect, when I look at the pages that link to it I could easily think, meh, it's not even used by 50 pages, why not start making a series of small edits as long as they preview OK? Its fast. Long story short, the overhead of a direct (non-virtual) function call was approximately 5.5 nanoseconds, or 18 clock cycles, compared to an inline function call. The overhead of a virtual function call was 13.2 nanoseconds, or 42 clock cycles, compared to inline. These timings are likely different on different processor families. -Wikid77 (talk) 12:07, 24 March 2013 (UTC). . Felicia Hagler - via Google, In the middle of a big move and so far Jay Casey has been immensely helpful to us with all the details! After your basic game engine is implemented, start with writing new code in Lua. However: This overhead may be trivial compared to what the body of
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