Respond to an unknown method call: Difference between revisions

=={{header|FreeBASIC}}==

FreeBASIC does not support object-oriented programming, but we can handle the invocation of an undefined method on an object using a data structure such as a dictionary that maps method names to functions. If the method is not defined in the dictionary, you can provide a default response.

<syntaxhighlight lang="vbnet">Type Method

Func As Function() As String

End Type

Function DefaultMethod() As String

Return "no such method"

End Function

Type Objeto

Methods As Method Ptr

End Type

Sub Invoke(obj As Objeto, methodName As String)

If methodName = "exists" Then

Print obj.Methods->Func()

Else

Print DefaultMethod()

End If

End Sub

Function exists() As String

Return "exists"

End Function

Function CreateObject() As Objeto

Dim As Objeto obj

Dim As Method met

met.Func = @exists

obj.Methods = @met

Return obj

End Function

Dim As Objeto o = CreateObject()

Invoke(o, "exists")

Invoke(o, "non_existent_method")

Sleep</syntaxhighlight>

{{out}}

<pre>exists

no such method</pre>