lua function call overhead

lua.LVAsBool(v LValue) - Convert to bool, nil and false becomes false. sol2 is a fantastic library which Ive used for many years. You can call a function with a number of arguments different from string.format('%f %f %f', 0.00001, 1.2, 3) => 0.000010 1.200000 3.000000, string.format('%g %g %g', 0.00001, 1.2, 3) => 1e-05 1.2 3, This page was last edited on 4 February 2023, at 15:13. At Module:DisplayLuaTableContents I see numerous loops as, , but I learned that strings are immutable and hence this assignment is rather costly. WebLua programs can emit signals using the function call syntax. In our C++ file, we need to define the consoleLog function that it will receive from JavaScript. You dont need to compile Lua code, which means that you can change parts of your program/game logic without recompiling and even without reloading your program. A cross between resources, documentation, and useful links. We have an even split on people who do personal testing in Sandbox/ and people who do it in User: At this point, either of us could pull up stakes and migrate to the other pretty easily. That is partly about performance but mostly about engine architecture. ), You dont need a specialized IDE or tools to write Lua comfortably. to use Codespaces. I think that this is less effective than it could be, however. They are iteration functions, so they add the overhead of a function call to each loop iteration. Your help pointing to ways to improve is welcome. Is there a way to obtain a list (array) of all pages with a prefix (e.g. You can learn about how to use Lua C API here (or in the latest version of Programming in Lua) - the online version is written for Lua 5.1 and some things have changed since 5.1, but most concepts have stayed the same. That's a bit of boilerplate code that I've been using in all the modules I write. An expression like o:foo(x) For instance, all library functions are written in C; A tag already exists with the provided branch name. (alright, the bot might miss that one, unless it knows to go back and check a template by the same name also, but you understand) My feeling is that if the reuser is going to put millions of pages on the queue, he should have the chance to decide whether he wants the latest update in the module to be passed along, or if it can wait. Automatic transclusion of protection templates was added. Hex (? The sandbox Wiki code {{Special:AllPages|namespace=666}} {{CURRENTTIMESTAMP}} returns a timestamp that changes each time the page is reloaded, because caching is disabled. !) 16:39, 24 February 2013 (UTC), the following code is arguably better than the current one;-) [Note: It also highlights more Lua features - assertion, type checking, local scoping, tail call recursion etc. but this fact has no relevance to Lua programmers. Download the official Lua source code here: https://www.lua.org/download.html. Work fast with our official CLI. Thank you for your attention!--Qgil (talk) 21:16, 2 July 2013 (UTC), I created Module:Testcase table, and it seems to work pretty well (see the current transclusions). Its stable. So its better to do it on Lua side, unless you make a C++ API which has to accept tables for ease-of-use - then you dont have much choice (but you can still wrap them into Lua functions and call C++ function internally). --Jarekt (talk) 16:24, 14 March 2013 (UTC), Are module authors permitted to use other licenses (presumably in addition to the CC-BY-SA license) for modules they develop? I'm a rookie! Even if you do, with LuaJIT youll be able to achieve C/C++ level performance. If you only want to call some C/C++ functions from Lua (or some small Lua functions from C/C++) - use Lua C API. 3 Should I return a sequence of hundreds of strings relying on Scribunto in concatenating it? An auto sizing callstack will allocate and release callstack pages on demand which will ensure the minimum amount of memory is in use at any time. Please let me know your thoughts over at Template talk:Pagetype#Module:Pagetype. Page content can be retrieved with the getContent () method of the title object. now i wanted to translate Category:Pages with script errors in bn language. However, sometimes that is just not enough and an embedded language can be the solution. If so, I can add Module:WikiLink to d:Q14746829. or subroutine in other languages) The typecheck function could also store away the type info for later introspection. E.g. There is still lots of work to do of course, But it's a start TheDJ (talk contribs) 22:18, 18 March 2013 (UTC). mw:Extension:Scribunto/Lua reference manual, Getting started ("hello world") portion of the Lua reference documentation, Sumana Harihareswara, Wikimedia Foundation Engineering Community Manager, MediaWiki:Scribunto-doc-page-does-not-exist. A language variable can contain values of any type. ( Since Lua has lexical scope at the block level rather than the function level, this works similarly to the way Python calls __exit__. He has also implemented a number of incredible little libraries which Ive used in my projects: Many other great libraries can be found via LuaRocks: https://luarocks.org/. Fantastic help. Technical 13 (talk) 12:12, 9 May 2013 (UTC). If nothing happens, download Xcode and try again. Ive written many articles about using Lua with C++ on my old blog many years ago. For example (C++ functions have cpp postfix): Ask yourself: do all these functions need to be in C++? This came up over at Template talk:Historical populations. Can someone make a nice SpecialPages adjustment? WebDue to the short-circuiting behavior of or, it will generally impose little additional overhead at call-time: local soundit; do local sounds; function soundit (x) sounds = sounds or { a = "ay" , b = "bee" , c = "see" , . } assert ( type (x) == "string" ) return sounds [x] end end with nil arguments removed. To maintain similarity with other sandbox pages (in template space and user space), I propose: If we agree on this, we can encourage/discourage patterns. 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! --Iantresman (talk) 13:14, 8 December 2013 (UTC). Clearly it's worth thinking about ways to reduce this impact as much as possible. Johnuniq (talk) 22:58, 10 January 2014 (UTC). Result #3 works correctly. Integrating it with CMake is somewhat trickier. All values in Lua can be stored in variables, used as arguments when calling functions, and returned as the result of their execution. I think it really depends on the language and on the function. While the c and c++ compilers can inline a lot of functions, this is not the case fo the colon operator. is just another way to write o.foo(o, x), If you'd like to make a request, please do that too! 1 time resty -e '' We can see theres overhead of about 11 milliseconds on this machine. Then, executing script.lua would resullt in an error: SomeClass is nil. 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. is there a better way to do this? (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? laura lehn - via Google, I highly recommend Mayflower. The process was smooth and easy. its hard to know if what youre passing to Lua will be copied or passed by a reference). Extra arguments are thrown away; I was just trying to return those hex tables via loadData and seem to have run into a nasty surprise. Otherwise false. I've taken some steps to bring it partially in line with our Template documentation system. Dont put too much code into one script - its easy to separate everything into smaller scripts. lua.LVAsString(v LValue) - Converts LString and LNumber to string. The body of the compiled Lua function consists of a series of function calls to the helper functions, one per instruction. 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). Thats basically all youll ever need to know about Lua. Writing the code in it feels like writing pseudocode/prototyping. Frietjes (talk) 00:03, 4 July 2013 (UTC), At the moment we have the {{lua talk}} template to use on talk pages of templates converted to Lua. Can one call lua function that returns sevaral strings and pass them to a template? Our compilation still gets rid of the run-time Running the Go code will yield: To run a Lua file, instead of a string, call lua.DoFile, DoFile and DoString can be called several times, and thus it can be utilized to expose Lua function. Preceding unsigned comment added by Ryn78 (talk contribs) 03:27, 13 October 2013 (UTC), Is it possible for a module to invoke another module? It has a GNU Make build, so building it is easy. : Overusing them makes code harder to understand because now you need to make sure that the object youre are pointing to doesnt change unexpectedly. Are you sure you want to create this branch? It doesnt have many gotchas. Thank you. Is this the right place for Lua programming queries? You might also find Moonscript interesting. The parameters object takes three important parameters: Fn - the lua.LFunction to call Nret - The number of returned values Protect - If protect is true an error is returned, otherwise a panic will occur. Needs study to guarantee correctness! -- Sameboat - (talk) 04:26, 19 March 2013 (UTC). Many Git commands accept both tag and branch names, so creating this branch may cause unexpected behavior. 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. Calling Lua code is done through L.CallByParam, which takes a parameters object, P, and arguments as variadic parameters. WebLua scripts have the same capability with calling MMF events. This was possible because the wikimarkup language was very intuitive, and easy to understand even for the layman. Have there been any major incidents yet? The functions in question had a single parame You can find Luas reference manual here. There are some practical functions to convert and check lua.LValue objects. For example, Module:User:Mr. Stradivarius/sandbox2 produces the right result when used via invoke from User:Mr. Stradivarius/Sandbox, but when I use the code = p.test() in the debug console I get the error "Lua error at line 4: attempt to index local 'frame' (a nil value)." in C (or in any other language used by the host application). A very simple test is: Result #2 is brokenthe first line includes a working wikilink (should not happen inside pre, but would happen if had a single space at the beginning of the line, with no pre). WebBut when you create thou sands of small tables, the combined overhead can be signic ant. 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. There are still a few things I'm not sure about, though. A fixed size callstack has the highest performance and has a fixed memory overhead. Plastikspork (talk) 22:08, 2 November 2013 (UTC), I've created Module:Pagetype, a replacement for {{pagetype}}, and I am thinking of updating the template to the Lua version later on this week. Is a module supposed to do something clever in order to output tags? For example, return {84 = 132}, or return {'84' = 132}, or return {0 = 00}, give errors demanding a } near the =. I've created a new request page for Lua scripts at Wikipedia:Lua requests. Similar to avoiding use of prior utility templates, when writing other utility templates, I would recommend to use the direct #invoke to access Lua functions from a utility template. For infoboxes, which use just a few Lua functions, then running the shell-template versions, rather than direct #invoke in the infobox, would be efficient enough, but still must beware the +2 expansion depth when running a shell-template version instead of direct #invoke in the infobox. Installation You can download the latest release manually and include See discussion at Village Pump (policy)#Protection and management of scripts?. I measured the overhead of direct and virtual C++ function calls on the Xenon PowerPC some time ago. With your own bindings, you can control what version you use and how the exposed API looks in Lua. How do I fix this? initialized with the actual arguments given in the function call. The easy part is 'getting rid of the function name': assuming p is the variable in the last line of the program, just say, However, I see no way to get rid of the pipe - it. -- The parentheses remove the "number of changes" returned by gsub. ], So templates can call Lua modules, parser functions and pages in MediaWiki namespace. = To get the perf bit How you divide up your code among different We have a lot of cases where related modules have the same name with "/" to indicate subpages, and some others where apparently related modules simply extend a name. I very much regret that. What am I doing wrong? The redis instance enables the script to interact with the Redis server that's running For example: Instead I need to output: "0.00001 1.2 3". 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? To simplify comparisons, when comparing metadata the following can always be assumed to be true: From this data or according to any other criteria, the handler function should resolve the conflict by returning the value that should be written to the conflicted key. The function signature must match what you passed in. The value of any of these keys will never be. 2000 What I'm trying to do is much more complicated, see Module:Convert/makeunits, but is the same issue. 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. 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. Mr. Stradivarius talk 01:15, 29 October 2013 (UTC), How well does Scribunto defend itself against DoS, or possibly XSS, but especially DoS as we are dealing with a Turing-complete language? This first edition was written for Lua 5.0. 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. Its easy to integrate Lua scripts into C/C++ projects. To get the perf bit out of the way: the bridging code between C++/Lua has overhead compared to just calling Lua from Lua or calling C++ from C++. A complete example looks like this: The LState defines some convenience functions, in the example above we are using L.ToInt(1) to fetch the first function argument. In this case we will embed Lua using gopher-lua. Lua is written in ANSI C, so it can compile almost everywhere. With those it's not entirely clear if they are meant to go together or not. I would use them again if needed. You can do procedural, functional, OO programming. I'm a happy user of this space myself with the pet projects I develop in my free time. Please don't take those *personal* suggestions as a criticism to Wikipedia:Lua. ), The disadvantage of course is that bugfixes in modules like Redirect don't get passed on. DePiep (talk) 23:55, 21 May 2015 (UTC). Will your logo be here as well?. thank you. 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. You signed in with another tab or window. d We really ought to decide, flip a coin, something so we get this sort of stuff to a predictable spot. The fact that even an IP user may edit the module namespace suggests that it must be really stable and secure. Command line parameters, environment variables, and configuration files are common ways to change the behavior of software. itch.io was written with it and it compiles to vanilla Lua. !) 16:49, 3 April 2013 (UTC), I've created five categories for different levels of Lua module progress: since each explains the others, Category:Modules in alpha should be sufficient. Is there a way for a loadData table to contain these keys? Now you dont need to ship this init.lua with your binary and life becomes easier. Makyen (talk) 05:58, 1 January 2014 (UTC), That makes sense. For example, I might want to process the posts on a talk page, and add some extra formatting. (and object-oriented programming) in more detail. The less data is shared between C++ and Lua, the better. The LTable type can be used for emulating namespaces and classes. Similarly to the previous advice, when defining classes (e.g. The docs are fantastic too. {\displaystyle d=3^{(n/2000)}.} The first question, of course, is whether we should require() at all. It may sound like asking to be babysat or spoon-fed, but I'm totally stuck. Please comment over there if you're interested. Makyen(talk) 04:02, 8 May 2014 (UTC), I've heard for quite a while that the Lua scripts only run when the page is parsed, which rules out many interactive features but is efficient. that is, to call o.foo adding o as a first extra argument. 1 time resty -e 'ngx.re.find ("hello, world. I'm currently using the following function to get template arguments. 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. ]], "jo")' But there is a catch. 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. Where I see this is commonly done is in the templates which return links to the archives of talk pages. WebWe can disable all the type checking by switching a single variable, and no added overhead would remain when the functions are executed (though there is some slight added overhead when the functions are built). During operation, in the event that any functions share the same name, a table will be created with that name and the conflicting functions will be stored there using the name of the script they came from, such that with two scripts foo and bar, both containing the function foo, you would end up with the functions foo.foo and foo.bar. also, if someone already wrote a module that does the same thing, let me know and I will have this one deleted. You just compile a bunch of C files, link with the library and youre ready to go - you dont need to rewrite half of your program/game or make your build script 10 times more difficult. If you create a local object inside the coroutine and store the reference to it in C++. Thanks! The problem with 3rd party bindings is that they usually tend to get unmaintained or only support a specific version of the library. See the demos and more details at WikiProject Flag Template. thank you. for example, make this work without copying the args to a new table? WebTo call a Lua funcion, we first push the function onto the stack. In the example bellow sayHello function is first defined, and then called in the second call to DoString. What to write in Lua: gameplay logic, FSMs, cutscenes, etc. Formula: Note: Lua isnt zero-indexed, so the first function argument is fetched with L.ToInt(1), second argument with L.ToInt(2). Its much easier to test if something is non-nil or has a specific type/fields in Lua than in C++. NeoVim, which uses Lua scripts for user script code. For example, Module:Navbar contains the code: In what case would frame not be equal to mw.getCurrentFrame()? The simplest language I know. Toohool (talk) 17:18, 27 March 2013 (UTC), I have another related question. The syntax of the template sends another template as parameter. Basically, you need to tell Lua explicitly that something youve created in the coroutine needs to outlive this coroutine (and this is done with lua_xmove). :P Anyway, I have taken that idea and added some parameter checking and some documentation, and called it Module:User:Mr. Stradivarius/PrefixIndex. Does someone have an idea how to code this feature? It is superfluous if you only call the function once within the scope of the local variable, but that is pretty rare. Thanks. Hex (? 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 . The gopher-lua library operates on a interface called LValue. Writing code like this will become better with new #embed directive in future C/C++ versions, e.g. If that is not possible: Please suggest an alternative method to implement it. To be sure, this is the strip marker for a current time function, but I'm thinking this is either a bug or a feature, and we should figure out which! Does this apply if you are accessing the module from another Lua module, and not directly from a wiki page? Any suggestion on how to receive this parameter template as a table rather than a substituted string? However, if we standardize this, with the names copied verbatim and the fairly distinctive capital letter after the /, it should be easy to have a bot notify the author(s) of Module:Submit an edit request automatically when Redirect is updated. Its a road map for learning Lua and my advice for how to integrate it with C/C++ code. Its minimalistic, but requires a lot of boilerplate and manual error-checking. WebThe Lua interpreter offers two hooks for debug purposes: typedef void (*lua_CHFunction) (lua_Function func, char *file, int line); extern lua_CHFunction lua_callhook; typedef void (*lua_LHFunction) (int line); extern lua_LHFunction lua_linehook; The first one is called whenever the interpreter enters or leaves a function. Ive used LuaDists CMake build scripts for Lua for many years, but LuaDist authors have stopped supporting newer Lua versions. However, the basic API is quite simple, and the advanced features deserves its own post. These functions does not throw errors, but will return Go default values if conversion is not possible. Enrique Garca Cota has a lot of great articles about Lua: http://kiki.to/. Functions can both carry out a specific task Time-delay formula: The initial tests show a time-delay formula as roughly delay=3^(n/2000) seconds, where n is the number of parameters passed, and for n=6,000, the delay has been 3^3 or 27 seconds, or for n=7,000 then the delay has been 3^3.5 or 47 seconds. Automatic insertion of the green 'chrome' of our template documentation. 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. Instead of requiring Module:Redirect from a protected module (or in this case a template, Template:Submit an edit request, which serves MediaWiki:Protectedpagetext), you would simply require or link to a copy (Module:Submit an edit request/Redirect). We are proud to provide our customers with these services and value by trained professionals. It stays global and doesnt get collected by a GC until it has been set to nil. Theyre mostly written in C/C++ and only expose a bunch of Lua functions/tables to the user. (what is sometimes called procedure The parameters object takes three important parameters: The following code defines a concat function in Lua. 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.

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lua function call overhead

lua function call overhead