5 replies to this topic

[Andi]

Hello,

I'm looking for a way, catching the error: "call to non-existent function" via errorlevel or something like this.
So when I start the script and ahk comes to the FunctionThatDoesNotExist() I want to avoid stopping the program. Instead it should be possible to react by the program to this error.

Any help would be appreciated!

Best regards,
Andi

[SKAN]

You can suppress the error by calling the function dynamically:

v1.0.47 released: Stdlib, RegisterCallback, NumGet/Put posted by Chris

Added dynamic function calling. [developed by lexiKos]
Description: A function (even a built-in function) may be called dynamically via percent signs. For example, %Var%(x, "fox") would call the function whose name is contained in Var. Similarly, Func%A_Index%() would call Func1() or Func2(), etc., depending on the current value of A_Index. The called function's definition must exist explicitly in the script, either via #Include or a non-dynamic call to a library containing the function. If the function does not exist -- or if the wrong number or type of parameters is passed to it -- the expression containing the call produces an empty string.

Func=SubStr
Result := %Func%( "Skan",1,2 )
If ( Result = "" )
    {
      MsgBox, 16, Fatal Error,Function %Func%() Not Defined,5
      ExitApp
    }
Else
 MsgBox, % Result

Func=SubString
Result := %Func%( "Skan",1,2 )
If ( Result = "" )
    {
      MsgBox, 16, Fatal Error,Function %Func%() Not Defined,5
      ExitApp
    }
Else
 MsgBox, % Result

[Andi]

Thank you Bobo and Skan

When I understand it right, the hint from BoBo with #ErrorStdOut stops the script. But I'm searching more for a solution that Skan descibes that keeps the script running. But additional I want to add the missing function to the lib folder.

So I tried the following, but there is one thing I don't understand: When the last but one line is missing, it leads to an error :roll:

Func=SubStr
Result := %Func%( "Skan",1,2 )
If ( Result = "" )
    {
      MsgBox, 16, Fatal Error,Function %Func%() Not Defined,5
      ExitApp
    }
Else
 MsgBox, % Result


ifNotExist %A_Scriptdir%\lib\subString.ahk
	{
		ifNotExist %A_Scriptdir%\lib
			FileCreateDir, %A_Scriptdir%\lib
		FileAppend,
		(	;only for testing
			Substring(String, StartingPos, Length)
				{
					return SubStr(String, StartingPos, Length)
				}
		), %A_Scriptdir%\lib\SubString.ahk
	}


Func=SubString
Result := %Func%( "Skan",1,2 )
If ( Result = "" )
    {
      MsgBox, 16, Fatal Error,Function %Func%() Not Defined,5
      ExitApp
    }
Else
 MsgBox, % Result
 
;The function above:
;Func=SubString
;Result := %Func%( "Skan",1,2 )
;works only, when the following line exists!? 
Result := Substring( "Skan",1,2 )
 MsgBox, % Result

I have to correct me: The first time you run the script, the last but one line stops the script. So when you run the first time without it, you see the error message from the msgbox. But when you run it a second time with the last but one line it doesn't work?!

[SKAN]

What you are trying to accomplish is not possible as on date.
AHK reads the whole script before it will execute a single line of it.
You will need two scripts, where the first script will check for dependencies and set things right and then load the target script.

[Andi]

Thank you Skan for the clarification

I skiped the following sentence :oops:

The called function's definition must exist explicitly in the script, either via #Include or a non-dynamic call to a library containing the function.