ExecFunctionStr

[Bleeder91[NL]]

Code: Select all

// Call a function by name and string parameters.
// Parms are separated by '\' character, diferent parms can also be enclosed by citate char, as ex:
// ExecFunctionStr('TestCode',"45\\\"Hello world\");
// Which will compile as: 45\"Hello world"
// Returns True if function was found and executed.
// @ ReturnValue = filled with the return value if exists.

native(390) final function bool ExecFunctionStr( name FuncName, string Parms, optional out string ReturnVal );

I don't get how this works. I'm using it like this:

Code: Select all

// The Data Actor.
Function HandleData(name Action, string PActorName, string PPlayerName)
{
      log(PActorName @PPlayerName);
}

// The Calling Actor.
Data.ExecFunctionStr('HandleData',"Load//" $string(PlayerActor.Name) $"//" $PlayerName);

It'll return "" for me in the log. The description for it is incorrect or something. I am forced to use 2x "\" because else it'll give an unfinished string error, which is 'obvious', that I get. But how does it know what param I'm giving in my example? And in the example the \ is inside the "" so shouldn't it be returning "hello world\"? I'm confuzzled. :-/

[yrex .]

The description seems to be missing the last ", otherwise it would probably make syntax error.

The \\ seems to evaluate to \, and \" evaluates to the " character. (All of that defines the value of the string, it's not related to the "outer" quotations.)

So then in your case it should be:

Code: Select all

Data.ExecFunctionStr('HandleData',"Load\\\"" $ string(PlayerActor.Name) $ "\"\\\"" $ PlayerName $ "\""); 

Which would evaluate like:

"Load\\\"" -> Load\"
"\"\\\"" -> "\"
"\"" -> "

E.g. Load\"actor name here"\"player name here"

I wonder what if somebody actually wanted to pass the " or \ to a parameter here...

[Masterkent]

I can only tell a few facts based on my own observations (no idea how ExecFunctionStr is implemented, because I don't have its source code; maybe if you pay Smirftsch $1000, he will tell you how this function really works).

Firstly, the real argument separator is comma, not backslash. I couldn't notice any special handling of backslashes by ExecFunctionStr - they seem to be treated as regular characters. Of course, within string literals (which are transformed into strings by the UScript compiler), backslashes have special meaning (they form escape sequences), but this feature is not related to ExecFunctionStr.

For example, if we have

Code: Select all

function SomeProc(string S, int I, float F, Object Obj)
{
      BroadcastMessage(S $ "," @ I $ "," @ F $ "," @ Obj);
}

then

Code: Select all

ExecFunctionStr('SomeProc', "One\\Two,123,3.14," $ Level);

has the same effect as

Code: Select all

SomeProc("One\\Two", 123, 3.14, FindObject(class'Object', string(Level)));

Secondly, enclosing arguments by " does not work as described in the comments. It simply messes up argument passing and does not do anything useful. So, as long as you don't need to pass strings containing commas or strings starting with ", ExecFunctionStr may work well for you (if you don't trigger any undocumented "feature" of this function somehow).

Native functions such as Destroy and SetTimer cannot be called via ExecFunctionStr (even though ExecFunctionStr reports successful execution by returning true).

[Bleeder91[NL]]

Thanks for the responses! Indeed a comma instead of a backslash does the job. For some reason this also sounds more logical since that's actually used to set params in a normal function call, oh well.
I'm using it together with dynamicloadobject to call actors that I don't want referenced i.e. clients don't have to download it. So this function, albeit hard to understand without the proper knowledge, does this just right.