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Lua Error Handling


The return values of pcall are either true, followed by the return values of the function, or false, followed by an error message. In such case, the C++ code might pcall into Lua and convert any error message to a C++ exception, which propogates up to the C function. more stack exchange communities company blog Stack Exchange Inbox Reputation and Badges sign up log in tour help Tour Start here for a quick overview of the site Help Center Detailed You can also use Lua RAII mechanisms. check over here

Advisor drops MSci student suddenly in final semester What do I do if somebody asks me to join his accusation of my colleague of academic misconduct? Neither does it have class. BUT keep in mind that tbl:method(arg1, arg2) in Lua is syntax sugar for tbl.method(tbl, arg1, arg2). What's the verb for "to drink small amounts of drink"?

Lua Error Function

This function error never returns. Therefore, it can be useful to make the lua_CFunction local to the calling function (like a closure). In this case, __index is triggered whenever the caller tries to look up some key that does not exist in the table. If that function (or any function it calls) calls error (assert calls error if the assertion condition is not true), then flow control will return to the site of the pcall

Lua Reference 5.1 Manual: Background discussion: [2.7. finally!) 29 commits 1 branch 0 releases Fetching contributors MIT Lua 98.2% Python 1.8% Lua Python Clone or download Clone with HTTPS Use Git or checkout with SVN using the web 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 Lua Error Wow The error message identifies the kind or error.

Instead of erroring, I want it to run this piece of code "comp.AddTool('PolylineMask', -32768, -32768)". Lua Pcall Example Once it runs, shows a run time error. It is called differently, however. else ...

Personal Open source Business Explore Sign up Sign in Pricing Blog Support Search GitHub This repository Watch 1 Star 2 Fork 1 dmccuskey/lua-error Code Issues 0 Pull requests 0 Projects Lua Xpcall Example How does the Spousal Surcharge generally work? coroutine.resume(co) -- false, cannot resume dead coroutine Coroutine works like a thread, however, the pausing and resuming is done in the code, not in OS level. Since function is first-class citizen, a table in Lua can hold values and functions, which is essentially the object.

Lua Pcall Example

The lua_cpcall, which is outside the protected call, is safe because it does not generate a lua_error() (unlike using a lua_pushcfunction followed by a lua_pcall, which could lua_error on memory allocation Using one instead of the other can lead to an error. Lua Error Function If you come from Ruby world, fiber in Ruby (added in 1.9) is quite similar to coroutine. Lua Xpcall For example, see [PIL 25.2] or PIL2 25.3. (Details on these conditions are given later below by Rici.) It's often the case that this lua_CFunction is used by only one caller.

Also, remember: Lua is a garbage collected environment. share|improve this answer edited Jul 25 '13 at 15:18 answered Jul 24 '13 at 21:54 Mud 18.4k53458 1 this won't work. your lua code should look more something like this: local ok, err = pcall(comp.ActiveTool, comp) if not ok then print(err, 'nothing selected') comp.AddTool(...) else -- the call succeeded print 'Node Selected' That’s the end of my introduction to Lua. Lua Pcall Arguments

First, none of the stack adjustment functions throw errors; this includes lua_pop, lua_gettop, lua_settop, lua_pushvalue, lua_insert, lua_replace and lua_remove. LuaError(lua_State * L); LuaError(const LuaError & other); ~LuaError(); virtual const char * what() const throw(); }; static void LuaError_lua_resource_delete(lua_State * L) { lua_pop(L, 1); } LuaError::LuaError(lua_State * L) : m_L(L), m_lua_resource(L, It has 7-pointed leaves How can Data be property of Starfleet? this content I'm not too familiar with error handling in Lua, but I believe there are a few functions that'll do what you want. –Will Jan 2 '12 at 2:30 @Will

If you have comment, you can post it HN (link can be found at the end of the essay), send me an email at ruoysun AT gmail DOT com or ping Lua_pcall Error Handler Example Open in Desktop Download ZIP Find file Branch: master Switch branches/tags Branches Tags master Nothing to show Nothing to show New pull request Fetching latest commit… Cannot retrieve the latest commit In Lua, OOP is usually done via table.

If you need to handle errors in Lua, you should use the pcall function (protected call) to encapsulate your code.

A simple example to show run time error is shown below. Listing sequence with rules delete the numbers uniq -c created Dynamic SOQL query What is this game from this promotional image for joysticks? end Then, you call foo with pcall: if pcall(foo) then -- no errors while running `foo' ... Lua_error Here are some alternate layouts showing the same thing: flattened out: try{ , catch{ }, finally{ } } same thing, including parens: try({ , catch({

Not the answer you're looking for? This is working well. –iGwok Jul 25 '13 at 8:29 add a comment| up vote 1 down vote You aren't using pcall correctly. Although, for the life of me, i cannot figure out how an exception can be handled without the plumbing provided by the language infrastructure. have a peek at these guys Example The following code snippet is a real-life example taken from dmc-wamp: try{ function() self._session:onOpen( { transport=self } ) end, catch{ function(e) if type(e)=='string' then error( e ) elseif e:isa( Error.ProtocolError

Should I defragment my SSD? metatable is a normal table with special keys that are hooked up to events. Permalink Failed to load latest commit information. If you provide incorrect indexes to these functions, or you haven't called lua_checkstack, then you're either going to get garbage or a segfault, but not a Lua error.

Any help would be greatly appreciated! How to use breakpoints for debugging I'm looking for some mathematics that will challenge me as a year 12 student. This is a runtime error, which had occurred due to not passing two variables. And you cannot force a coroutine to pause at any time - coroutine only pauses at the point you have specified.

This StackOverflow answer is particularly useful in understanding the concept. A simple example using pcall is shown below. This can be convenient for simple functions. More often, the error needs to be dealt with at a more shallow point in the call chain.