I'm getting bit confused
hopefully somebody can put me straight
i have function
which works as i would expect in the playground
func testFunction(Astring:String,Anumber:Int,Afloat:CGFloat)
{
println(Astring)
println(Anumber)
println(Afloat)
}
testFunction("Hello",25,25.00)
but in a project i have to call it like this, if i don't i get error missing argument label "Afloat:" in call
testFunction("Hello",Anumber:25,Afloat:25.00)
the only difference is I'm calling the function from a button?
thanks for the help of this site without it I would be lost
By default, parameters after the first parameter require you to use the external name. If you do not want an external name, then you have to define that in the function. Also as a style point, local variables should start with lower case. Regardless, this should get you what you want. The "_" character basically says no external name.
func testFunction(aString:String, _ aNumber:Int, _ aFloat:CGFloat)
Related
I am learning Julia programming by reading the book Think Julia I am including the following:
enter image description here
forward is a function in the ThinkJulia module. It acts on the Turtle() object, to move it forward. Why, after the line using ThinkJulia , am I getting this error. Do I have to be more specific in Julia about importing functions? I thought using would give me access to all functions in that particular module?
You need to pass a value not to its type to forward, so define your function like this:
function forward_len(t::Turtle, d)
forward(t, d)
end
and things should work
The error message is clear, you do not have forward method matching your parameter types.
Try 'Forward' instead of 'forward';
function forward_len(t::Turtle, d)
Forward(t, d)
end
Source: https://juliagraphics.github.io/Luxor.jl/v0.11/turtle.html
I have just started a new version of my Crysis Wars Server Side Modification called InfinityX. For better management, I have put the functions inside tables as it looks neater and I can group functions together (like Core.PlayerHandle:GetIp(player)), but I have ran into a problem.
The problem is that the specified method to get the players' name, player:GetName() is being seen as an invalid method, when the method actually is completely valid.
I would like to know if using the below structure is causing a problem and if so, how to fix it. This is the first time I've used this structure for functions, but it is already proving easier than the old method I was using.
The Code:
Event =
{
PlayerConnect = function(player)
Msg.All:CenteredConsole("$4Event$8 (Connect)$9: $3"..player:GetName().." on channel "..player.actor:GetChannel());
System.LogAlways(Default.Tag.."Incoming Connect on Channel "..player.actor:GetChannel());
Event:Log("Connect", player);
end;
};
The below code works when I bypass the function and put the code directly where it's needed:
Msg.All:CenteredConsole("$4Event$8 (Connect)$9: $3"..player:GetName().." on channel "..player.actor:GetChannel());
System.LogAlways(Default.Tag.."Incoming Connect on Channel "..player.actor:GetChannel());
The Error:
[Warning] [Lua Error] infinityx/main/core.events.lua:23: attempt to call method 'GetName' (a nil value)
PlayerConnect, (infinityx/main/core.events.lua: 23)
ConnectScript, (infinityx/main/core.main.lua: 52)
OnClientEnteredGame, (scripts/gamerules/instantaction.lua: 511)
(null) (scripts/gamerules/teaminstantaction.lua: 520)
Any clarification would be appreciated.
Thanks :)
Well, as PlayerConnect is inside the table Event, and you are calling with a ":", add self as first arg in the function, like:
PlayerConnect = function(self, player)
Clearly, player in the first block of code is not the same as player in the second block of code. The problem must be that the caller of Event.PlayerConnect is not passing the same value.
To test that your Event.PlayerConnect function works, try this in the same place as your second block of code:
Event.PlayerConnect(player)
That should work as you expect.
So, the problem comes down to how Event.PlayerConnect is called without the second block of code. I'm not familiar with that game engine so I don't know how it is done. Perhaps reviewing the documentation and/or debugging that area would help. If you print(player) or call the equivalent log function in both cases, you should see they are different. If you can't run in a debugger, you can still get a stack trace with print(debug.traceback("Accessing player, who's value is: "..player)). If there is indeed some kind of table-based player object in both cases, you can try comparing their fields to see how they are different. You might need to write a simple dumping function to help with that.
I work with a BASIC programming language and have found it useful to write functions that rely on their output as a parameter. Such as
inOut = someFunction(inOut)
I'd like to call this a recursive function. but it doesn't seem right because it is not calling itself. Can someone tell me what the name of this type of function is and if the parameter/return has a special name?
Thanks!!
This is an ordinary function as any other. The thing you show is called reassingment. You can rename inOut on the left with newinOut and it will not change anything... there is absolutely nothing special about the function, it's a naming pattern, that's all.
In many languages (including VB, but not sure about classic BASIC) there's something called passing parameter by reference. It's not exactly what you posted, but rather simple
someFunction(inOut)
parameter is passed into the function, changed there and the change persists outside the function
I'm having a problem with my code and I don't know what's up, I've searched online and the _Gx method was suggested as the best way over ones like loadstring(x)... although I would be happy with either, can't get either one to work. What I want to do is, in ComputerCraft, send a function name and argument to a turtle, which I'm doing by saving both values to a table and sending across the table, and then on the turtle's program, have a big list of functions, and using a command, call them from the string sent and insert the arg as well. My error is "attempt to call nil", which I don't quite understand why it's saying that... Thanks in Advance!
EDIT
I've edited my code down, as asked, to show that even stripping all else away, this still fails. I could even strip it down even more by taking the variable completely out, and putting the string straight into the _G. This still fails even doing it like that. I've decided to keep it in because that's how I am actually going to be using it later. Calling the function normally works fine. I'm using version Luaj-jse 2.0.3
function foo ()
print ("HI!")
end
print (_VERSION)
I don't know what rednet is, but it seems like you passes name of function to another Lua VM, which doesn't know anything about this function (this function is absent in that VM's globals table).
So, passing function definition as string and executing it by receiver with loadstring is the only solution.
I have been searching an entire afternoon and have found no solution to call in matlab a function by specifying its path and not adding its directory to the path.
This question is quite similar to Is it possible to call a function that is not in the path in MATLAB?, but in my case, I do not want to call a built-in function, but just a normal function as defined in an m-file.
I think handles might be a solution (because apparently they can refer to functions not on the path), but I again found no way to create a handle without cd-ing to the directory, creating it there and the cd-ing back. Trying to 'explore' what a function handle object is and how to make one with a reference to a specific function not on the path has led me nowhere.
So the solution might come from two angles:
1) You know how to create a handle for an m-file in a specific directory.
2) You know a way to call a function not on the matlab path.
EDIT: I have just discovered the function functions(myhandle) which actually lets you see the filepath to which the handle is referring. But still no way to modify it though...
This is doable, but requires a bit of parsing, and a call to evalin.
I added (many years ago!) a function to the MATLAB Central File Exchange called externalFcn
http://www.mathworks.com/matlabcentral/fileexchange/4361-externalfcn
that manages calls to off-path functions. For instance, I have a function called offpathFcn that simply returns a structure with a success message, and the value of an input. Storing that function off my MATLAB path, I can call it using:
externalfcn('out = C:\MFILES_OffPath\offpathFcn(''this is a test'')');
This returns:
out =
success: 1
input: 'this is a test'
(Note that my implementation is limited, and improvable; you have to include an output with an equal sign for this to work. But it should show you how to achieve what you want.)
(MathWorks application engineer)
The solution as noted in the comment 1 to create a function handle before calling the function is nicely implemented by #Rody Oldenhuis' FEX Contribution:
http://www.mathworks.com/matlabcentral/fileexchange/45941-constructor-for-functionhandles
function [varargout]=funeval(fun,varargin)
% INPUT:
% fun: (char) full path to function file
curdir=cd;
[fundir,funname]=fileparts(fun);
cd(fundir);
[varargout{1:nargout}] =feval(funname,varargin{:})
cd(curdir);
I've modified Thierry Dalon's code to avoid the use of feval, which I always feel uncomfortable with. Note this still doesn't get around cd-ing to the directory in question, but well, it happens behind the scenes, so pretend it doesn't happen :-)
Also note what Ben Voigt pointed out above: calls to helper functions off the path will fail.
function [varargout]=funeval(FunctionHandle, FunctionPath, varargin)
% INPUT:
% FunctionHandle: handle to the function to be called; eg #MyFunction
% FunctionPath: the path to that function
% varargin: the arguments to be passed to Myfunction
curdir=cd;
cd(FunctionPath)
[varargout{1:nargout}] = FunctionHandle(varargin{:});
cd(curdir);
end
and calling it would look like
Output = funeval(#MyFunction, 'c:\SomeDirOffMatlabsPath\', InputArgToMyFunc)
The run command can run a script file from any directory, but it can't call a function (with input and output arguments).
Neither feval nor str2func permit directory information in the function string.
I suggest writing your own wrapper for str2func that:
saves the working directory
changes directory to the script directory
creates a function handle
restores the original working directory
Beware, however, that a handle to a function not in the path is likely to break, because the function will be unable to invoke any helper code stored in other files in its directory.