How do I exit out of an awk function? "exit" stops entire program?
I think you want the return statement.
Related
I want to end a main sub from another sub.
Here is an example code to illustrate what I need to do:
Sub main()
endMainSub()
'do other stuff
End Sub
Sub endMainSub()
**'here I need a code to end main Sub**
End Sub
From endMainSub, I would like to terminate main sub before "do other stuff".
I need something like "End" in VBA.
End exists in VB.NET too, so you could use it. You should NEVER do so though. End simply stops executing the application at that point, with no regard for what state it might be in. It's like closing applications by using End Task in Task Manager, which I hope you use only as a last resort.
As suggested, you should be returning a result from the second method that indicates that the application should exit and the first method should explicitly choose to exit or not based on that, e.g.
Sub Main()
If EndMainSub() Then
Return
End If
'...
End Sub
Function EndMainSub() As Boolean
Dim result As Boolean
'Some work that sets result here.
Return result
End Function
I think you should use
Application.Exit
It's more object orientated and allows to execute all closing and disposing events. "End" still exists, but it will end immediately and no clean up routines will be executed.
I would like to know if there is an equivalent of Python's pass statement in VBA.
I am using Excel 2016.
The use of Stop (see this answer) seems to be the best thing to do if you are looking for some "non-statement" that you can use to insert a breakpoint, because the Stop command causes the code to break when it is reached, i.e. you don't even need to mark it as a breakpoint because it is one.
You might also like to consider using Debug.Assert some_logical_expression, which will break automatically whenever the logical expression evaluates to False. So Debug.Assert False would be equivalent to Stop, and Debug.Assert x = 3 would be equivalent to If x <> 3 Then Stop.
In Python you need the Pass, because otherwise the methods will not run.
In VBA, its perfectly ok if you leave an empty method like this:
Public Function Foo() As String()
End Function
Maby you are looking for the "Stop" statement.
The good thing about it is that it doesn't clear your variables.
It depends what are you trying to achieve.
You may declare a Label and then use GoTo Label e.g. declare a label (like Skip:)in your code where you want to jump if a condition is met and then use GoTo Skip
Below is the small demo code to give you an idea about this...
Dim i As Long
For i = 1 To 10
If i = 5 Then GoTo Skip
MsgBox i
Next i
Skip:
Something we can just put break point on while making sure it doesn't do anything else.
In c, that would be while(false);
What to do in vb.net?
If you always need it to break there you can put
Stop or Debugger.Break()
If you really want a No-Op for some reason (could this turn into a contest for the most ineffectual single line of code?!), how about these?
System.Threading.Thread.Sleep(1) - 1ms is unlikely to have a huge impact outside of a loop
Debug.Write("") - doesn't appear to output anything.
There is a legitimate use-case for this.
When a temporary breakpoint is required after the statement of interest and this is the last line inside an if statement, an extra no-op type statement is required to place the temporary breakpoint on.
In this case I use:
If someCondition >0 Then
doSomething
Space (1) 'Dummy line to place breakpoint
End If
This returns a string containing one space, but does not assign it to anything. I use it in VBA, but it's also supported in .net
My two cents...
You can combine any series of commands onto one line with colons:
If False Then : End If
Select Case False : Case Else : End Select
I've also made it into a sub. Then it gets a recognizable name of own:
'Definition...
Public Sub noop () 'Or Private, Protected, etc.
End Sub
'Usage...
Sub Main()
If sometest Then
noop
Else
MsgBox "test is false"
End If
End Sub
Very strange question, you could place a BreakPoint about anywhere in the code. But here are some useless lines :
Do While False
Loop
While False
End While
Even the following :
Dim hello = Nothing
Or this :
Format("", "")
A no-op statement is also useful as an aid to document code nicely and make it more easily understandable. You could for example put in a statement like A = A.
For example:
If MyNumber => 100 then A = A
Else:
I know this is an old query, but for what it is worth, my preferred solution to the original question is
Debug.Assert (vbTrue)
If you wanted, you could use a variable instead of vbTrue and then enable/disable all breakpoints in your code by changing one variable
Dim bDisableBreakpoints as Boolean: bDisableBreakpoints = vbTrue
'your code here
Debug.Assert (bDisableBreakpoints)
'rest of your code
Simply change bDisableBreakpoints to vbFalse and the breakpoints will be set wherever you have used Debug.Assert
My personal favorite is
dim b=1
Then I put a breakpoint there.
Both "Exit Sub" or "Return" seem to accomplish the same thing -- exit a subroutine. Is there any difference in how they work under the covers?
That is,
Private Sub exitNow()
Exit Sub
End Sub
or
Private Sub exitNow()
Return
End Sub
From the doc:
In a Sub or Set procedure, the Return statement is equivalent to an Exit Sub or Exit Property statement, and expression must not be supplied.
So they're the same in this context.
(Return (<value>) is used in functions and property.get's. Obviously slightly different in that context).
I tend to prefer Return over Exit Sub. Because once in a while you change from Sub to Function. In this case Exit Sub could be converted to Exit Function, but this assumes that there was a previous assignment to the function name (alike VB 6), which most probably didn't happen. Return would catch this situation - if the method should return a value, Return with no argument will fail at compile time.
If you inspect the IL output of the 2 statements, they are the same. However, since ’return’ is meant for pushing something back to the caller, so strictly speaking, ‘Exit Sub’ is more suitable for using in a Sub.
They are the same in this context.
However, from the code readability point of view, "Exit Sub" would be clearer since the "Return" indicates that something some value is being used as an output (which is not the case with Sub-routines).
First of all, Procedures comes with sub, we should know that we are working on specific procedures that don't return a specific value with the ability of passing some specific parameters or even without passing any parameter. Such as:
Print something().
Calculate the factorial of integer number CalcFact(X).
Do some processes for a specific task.
Function is a specific process programmed to achieve a specific task by also passing some specific parameters, and it has to return some value that can be used to to complete the overall task, such as validation the user name and user pass.
In short Sub Doesn't return value and we call it directly "Print HelloWorld()" , whereas functions do such as:
ValidUsersNameAndPass("Johne","jOhNe13042019") ' This could return a Boolean value.
ValidUsersNameAndPass("Johne","jOhNe13042019"); // This could return a Boolean value.
I wanted to confirm that they act the same in lambda expressions too, and they do:
Sub test()
Dim a As Action = Sub() Exit Sub
Dim b As Action = Sub() Return
a()
b()
MsgBox("Yes they do!")
End Sub
While there are exceptions like guard clauses, in most cases I would consider either a sign that the method is too long.
I just moved over to the Visual Basic team here at work.
What is the equivalent keyword to break in Visual Basic, that is, to exit a loop early but not the method?
In both Visual Basic 6.0 and VB.NET you would use:
Exit For to break from For loop
Wend to break from While loop
Exit Do to break from Do loop
depending on the loop type. See Exit Statements for more details.
In case you're inside a Sub of Function and you want to exit it, you can use :
Exit Sub
or
Exit Function
Exit [construct], and intelisense will tell you which one(s) are valid in a particular place.