Passing a Function name as a procedure argument

1. I have a Standard Module Function:
Public Function GetARoot(ByVal FirstGuess As Double, ByVal
FunctionName As _
String) As Double
that calculates the root of an equation.

I have several equations programmed as Functions in the Standard
Module. I wish to pass the name of one of these Functions as an
argument to "FunctionName" and call the Function with this name from
inside GetARoot.

Can this be done?

Not if I understand you correctly, but you could pass an id and check that
with select Case and run the function accordingly

Select Case thisId
Case 1: myVal = Func1(a,b)
Case 2: myVal = Func2(a,b)
'etc.
End Select

--

HTH

RP
(remove nothere from the email address if mailing direct)


"[email protected]" <[email protected]> wrote in message
news:[email protected]...
> 1. I have a Standard Module Function:
> Public Function GetARoot(ByVal FirstGuess As Double, ByVal
> FunctionName As _
> String) As Double
> that calculates the root of an equation.
>
> I have several equations programmed as Functions in the Standard
> Module. I wish to pass the name of one of these Functions as an
> argument to "FunctionName" and call the Function with this name from
> inside GetARoot.
>
> Can this be done?
>

Thanks Bob, for a good robust solution. But would it be possible to do
it more elegantly like:

myValy= Fun1(a,b)

where "Fun1(a,b)" is passed in as a string or an object in the
parameter list?

Then if I write an new procedure, Fun3(c,d), I will not have to add it
to a case statement in the GetARoot procedure.

This is probably bad programming practice, but are there any ideas here that
can help?
Just step thru "TestIt" to follow the basic ideas. Good luck.

Sub TestIt()
'// Just call BasicFx
Debug.Print BasicFx("MyFx1", 2, 3)
Debug.Print BasicFx("MyFx2", 2, 3)
End Sub

Function BasicFx(Fx As String, x, y)
BasicFx = Application.Run(Fx, x, y)
End Function

Function MyFx1(a, b)
MyFx1 = a + b
End Function

Function MyFx2(a, b)
MyFx2 = a ^ 2 + b
End Function

HTH. :>)
--
Dana DeLouis
Win XP & Office 2003


"[email protected]" <[email protected]> wrote in message
news:[email protected]...
> 1. I have a Standard Module Function:
> Public Function GetARoot(ByVal FirstGuess As Double, ByVal
> FunctionName As _
> String) As Double
> that calculates the root of an equation.
>
> I have several equations programmed as Functions in the Standard
> Module. I wish to pass the name of one of these Functions as an
> argument to "FunctionName" and call the Function with this name from
> inside GetARoot.
>
> Can this be done?
>

No, that is exactly the point I was making, you cannot do that.

Here is another alternative, but only becomes useful I guess if all
functions have the same number of arguments

Sub TestFuncEvaluator()
Dim sFunction As String

sFunction = "func1"
Debug.Print Application.Run(sFunction, 11, 22)

sFunction = "func2"
Debug.Print Application.Run(sFunction, 11, 22)


End Sub

Function func1(val1, val2)
func1 = val1 * val2
End Function

Function func2(val1, val2)
func2 = val1 + val2
End Function

--

HTH

RP
(remove nothere from the email address if mailing direct)


"[email protected]" <[email protected]> wrote in message
news:[email protected]...
> Thanks Bob, for a good robust solution. But would it be possible to do
> it more elegantly like:
>
> myValy= Fun1(a,b)
>
> where "Fun1(a,b)" is passed in as a string or an object in the
> parameter list?
>
> Then if I write an new procedure, Fun3(c,d), I will not have to add it
> to a case statement in the GetARoot procedure.
>

WJG,

A good way to do this is to place your function(s) in a class module. Then
you can use the CallByName VBA method to "call" the desired function using a
string value...

Module Module1:
Sub test()
Dim M As New MathLibrary

CallByName M, "FuncA", VbMethod, 2345, 4321
CallByName M, "FuncB", VbMethod, 2345
End Sub

Class MathLibrary:
Public Function FuncA(a As Integer, b As Integer)
MsgBox "FuncA(" & a & "," & b & ")"
End Function
Public Function FuncB(a As Integer)
MsgBox "FuncB(" & a & ")"
End Function

BJ

"[email protected]" <[email protected]> wrote in message
news:[email protected]...
> 1. I have a Standard Module Function:
> Public Function GetARoot(ByVal FirstGuess As Double, ByVal
> FunctionName As _
> String) As Double
> that calculates the root of an equation.
>
> I have several equations programmed as Functions in the Standard
> Module. I wish to pass the name of one of these Functions as an
> argument to "FunctionName" and call the Function with this name from
> inside GetARoot.
>
> Can this be done?
>

Sorry for the double post but the following example is bit more to what you
need:

Module Module1:
Sub test()
Dim M As New MathLibrary

result1 = CallByName(M, "FuncA", VbMethod, 2345, 4321)
result2 = CallByName(M, "FuncB", VbMethod, 2)
End Sub


Class MathLibrary:
Public Function FuncA(a As Double, b As Double) As Double
FuncA = a / b
End Function
Public Function FuncB(a As Double) As Double
FuncB = a ^ 2
End Function


"[email protected]" <[email protected]> wrote in message
news:[email protected]...
> 1. I have a Standard Module Function:
> Public Function GetARoot(ByVal FirstGuess As Double, ByVal
> FunctionName As _
> String) As Double
> that calculates the root of an equation.
>
> I have several equations programmed as Functions in the Standard
> Module. I wish to pass the name of one of these Functions as an
> argument to "FunctionName" and call the Function with this name from
> inside GetARoot.
>
> Can this be done?
>

And I think you need xl2002 or higher to use CallByName.

"Mark H. Shin" wrote:
>
> Sorry for the double post but the following example is bit more to what you
> need:
>
> Module Module1:
> Sub test()
> Dim M As New MathLibrary
>
> result1 = CallByName(M, "FuncA", VbMethod, 2345, 4321)
> result2 = CallByName(M, "FuncB", VbMethod, 2)
> End Sub
>
> Class MathLibrary:
> Public Function FuncA(a As Double, b As Double) As Double
> FuncA = a / b
> End Function
> Public Function FuncB(a As Double) As Double
> FuncB = a ^ 2
> End Function
>
> "[email protected]" <[email protected]> wrote in message
> news:[email protected]...
> > 1. I have a Standard Module Function:
> > Public Function GetARoot(ByVal FirstGuess As Double, ByVal
> > FunctionName As _
> > String) As Double
> > that calculates the root of an equation.
> >
> > I have several equations programmed as Functions in the Standard
> > Module. I wish to pass the name of one of these Functions as an
> > argument to "FunctionName" and call the Function with this name from
> > inside GetARoot.
> >
> > Can this be done?
> >

--

Dave Peterson

Nah, 2000 has it.

--

HTH

RP
(remove nothere from the email address if mailing direct)


"Dave Peterson" <[email protected]> wrote in message
news:[email protected]...
> And I think you need xl2002 or higher to use CallByName.
>
> "Mark H. Shin" wrote:
> >
> > Sorry for the double post but the following example is bit more to what
you
> > need:
> >
> > Module Module1:
> > Sub test()
> > Dim M As New MathLibrary
> >
> > result1 = CallByName(M, "FuncA", VbMethod, 2345, 4321)
> > result2 = CallByName(M, "FuncB", VbMethod, 2)
> > End Sub
> >
> > Class MathLibrary:
> > Public Function FuncA(a As Double, b As Double) As Double
> > FuncA = a / b
> > End Function
> > Public Function FuncB(a As Double) As Double
> > FuncB = a ^ 2
> > End Function
> >
> > "[email protected]" <[email protected]> wrote in message
> > news:[email protected]...
> > > 1. I have a Standard Module Function:
> > > Public Function GetARoot(ByVal FirstGuess As Double, ByVal
> > > FunctionName As _
> > > String) As Double
> > > that calculates the root of an equation.
> > >
> > > I have several equations programmed as Functions in the Standard
> > > Module. I wish to pass the name of one of these Functions as an
> > > argument to "FunctionName" and call the Function with this name from
> > > inside GetARoot.
> > >
> > > Can this be done?
> > >
>
> --
>
> Dave Peterson

Thanks for the correction.



Bob Phillips wrote:
>
> Nah, 2000 has it.
>
> --
>
> HTH
>
> RP
> (remove nothere from the email address if mailing direct)
>
> "Dave Peterson" <[email protected]> wrote in message
> news:[email protected]...
> > And I think you need xl2002 or higher to use CallByName.
> >
> > "Mark H. Shin" wrote:
> > >
> > > Sorry for the double post but the following example is bit more to what
> you
> > > need:
> > >
> > > Module Module1:
> > > Sub test()
> > > Dim M As New MathLibrary
> > >
> > > result1 = CallByName(M, "FuncA", VbMethod, 2345, 4321)
> > > result2 = CallByName(M, "FuncB", VbMethod, 2)
> > > End Sub
> > >
> > > Class MathLibrary:
> > > Public Function FuncA(a As Double, b As Double) As Double
> > > FuncA = a / b
> > > End Function
> > > Public Function FuncB(a As Double) As Double
> > > FuncB = a ^ 2
> > > End Function
> > >
> > > "[email protected]" <[email protected]> wrote in message
> > > news:[email protected]...
> > > > 1. I have a Standard Module Function:
> > > > Public Function GetARoot(ByVal FirstGuess As Double, ByVal
> > > > FunctionName As _
> > > > String) As Double
> > > > that calculates the root of an equation.
> > > >
> > > > I have several equations programmed as Functions in the Standard
> > > > Module. I wish to pass the name of one of these Functions as an
> > > > argument to "FunctionName" and call the Function with this name from
> > > > inside GetARoot.
> > > >
> > > > Can this be done?
> > > >
> >
> > --
> >
> > Dave Peterson

--

Dave Peterson