I have simple function in VBA and I would need to check whether or not it has been successfully performed. I do not know VBA much, so I have no idea whether or not its possible. I want to do something like this: bool X=MyFunction().
I am using VBA in the QTP descriptive programming. This does not work:
Function A as Boolean
A=true
End Function
It says: Expected statement
But I cannot see any return type in my method etc.
function MyFunction() as Boolean
.....
.....
MyFunction = True 'worked
end function
dim a as boolean = MyFunction()
In VBA, you set a function's return value by assign to a variable with the same name as the function:
Function MyFunc() as Boolean
MyFunc = True
End Function
I suspect you may be using VBScript instead of VBA? If that's the case then VBScript doesn't state Type
this will work in VBScript
dim test,b
test = 1
b=false
msgbox ("Calling proc before function test=" & test)
msgbox("Calling proc before function b=" & b)
b = A(test)
msgbox ("Calling proc after function test=" & test)
msgbox("Calling proc after function b=" & b)
Function A(test)
test = test +1
A=true
End Function
or in your example
Function A()
A=true
End Function
There is no real way to check if a function worked in VBA. You must decide for yourself whether your function was successful. For example:
Function AFunction() as Boolean
on error goto 1
MyFunc = True
AFunction = True
Exit Function
1
AFunction = False
End Function
The above would let you know if the function failed. If it fails, it goes to the label '1' and then returns false, otherwise, it returns true.
If it isn't an 'error' you are looking for, then you must decide if the data returned or supplied is proper. One way of doing this is to return a specific value [error-code] which represents a failure.
Well if you have access to your function declaration, you can set a bool return type for it and return true or false depending on the execution.
Once your function returns a bool, your code will work.
Related
I have this code:
function test()
function awesome()
print("im awesome!")
end
function notawesome()
print("im not awesome.")
end
function notevenawesome()
print("im not even awesome...")
end
end
test().notawesome()
When I run this, the console prints
15: attempt to index a nil value
What I'm trying to do is call the function notawesome() within the function test(), how would I do that?
Your function is not returning anything (thus returning nil). Something like this should work:
function test()
function awesome()
print("im awesome!")
end
function notawesome()
print("im not awesome.")
end
function notevenawesome()
print("im not even awesome...")
end
result = {}
result["notawesome"] = notawesome
result["awesome"] = awesome
result["notevenawesome"] = notevenawesome
return result
end
test().notawesome()
#Axnyff explains what you might be trying to do. I'll explain what you did.
If you are familiar with other languages, please note that Lua does not have function declarations; It has function definitions, which are expressions that produce a function value when evaluated. Function definition statements, which you have used, are just shortcuts that implicitly include an assignment. See the manual.
When you run your code, a function definition is evaluated and the resulting function value is assigned to the variable test. Then the variable test is evaluated and its value is called as a function (and it is one).
When that function executes, three function definitions are evaluated and assigned to the variables awesome, notawesome, and notevenawesome, repsectively. It doesn't return anything.
So, when the result of calling test (nil) is indexed by the string "awesome", you get the error.
If you wanted to call the function value referred by the variable awesome, just do awesome().
If you want to achieve that instead to use the main function you can use an object:
test = {
awesome = (function()
return 'im awesome!'
end),
notawesome = (function()
return 'im not awesome.'
end),
notevenawesome = (function()
return 'im not even awesome...'
end)
}
To call your functions use this:
print(test.notawesome()) --> im not awesome.
function [TC]=Translate(T0,Base)
end
I know that Translate is a function and T0 and Base his parameter but what is [TC]?
Octave (and matlab) have a rather unique way of returning variables from functions. Instead of defining explicitly what to return from the function using a return keyword, they define from the outset which variables will be returned when the function exits, and octave simply looks for those variables by name at the time the function exits, and returns their values, whatever they may be by that point.
Your function may return nothing:
function returnsNothing();
disp('hello, I return nothing');
end
or it may return one output:
function Out = returnsOne(x)
Out = x+5
disp('This function will return the value of Out');
end
or it may return more than one outputs:
function [Out1, Out2] = returnsTwo(x)
Out1 = x+5;
Out2 = x+10;
end
You would call the last function from the octave terminal (or script) like this:
[a,b] = returnsTwo(5); % this will make a = 10 and b = 15
I need to get the variable a function's return value is assigned to.
function example()
end
variable = 3 --just for example
variable = example() --I need the value of variable(in this case 3) passed as an argument to example()
Please read the Lua reference on how to call and define functions.
https://www.lua.org/manual/5.3/manual.html#3.4.10
https://www.lua.org/manual/5.3/manual.html#3.4.11
You can simply do this:
function fancyFunction(val)
return val
end
local val = 3
val = fancyFunction(val)
of course this minimum example does not make much sense. You should of course have another return value than your argument. Otherwise you don't have to call the function in the first place.
(Quite hard to understand what you're trying to do.) Could you possibly be referring to object oriented programming? If so, then you need something like this:
--setup
t = {}
function t:set(v) self.value = v end --assign value to 'variable'
function t:get() return self.value end
--use
t:set(3)
print(t:get())
I found one topic that's about post hooking, but I don't think it's the same thing as I want to accomplish. topic i found
What I need is the following:
local someBoolean = false
function doSomething() -- this is the function used in __index in a proxy table
someBoolean = true
return aFunction -- this is function that we can NOT alter
end
I need to ble able to run the code "someBoolean = false" after the return... (yes, I know that's not supposed to happen :p) considering aFunction may contain other functions itself, I want someBoolean to be true for the entire scope of aFunction, but after that, it HAS to be turned back to false
I'm sorry if I didn't manage to explain it well enough. Copy pasting the relevant code of my actual project would be way too large, and I don't want to waste your time.
I've been stuck on this for a while now, and I just can't seem to figure it out...
(edit: I can't just put someBoolean = false after the function, because the function is actually an __index function on a proxy table)
edit: relevent piece of code. I hope it's a bit clear
local function objectProxyDelegate(t, key)
if not done then -- done = true when our object is fully initialised
return cls[key] -- cls is the class, newinst is the new instance (duh...)
end
print("trying to delegate " .. key)
if accessTable.public[key] then
print(key .. " passed the test")
objectScope = true
if accessTable.static[key] then -- static function. return the static one
return cls[key] -- we need to somehow set objectScope back to false after this, otherwise we'll keep overriding protected/private functions
else
return newinst[key]
end
elseif objectScope then
print("overridden protected/private")
return cls[key]
end
if accessTable.private[key] then
error ("This function is not visible. (private)", 2)
elseif accessTable.protected[key] then
error ("This function is not visible to an instance. (protected)", 2)
else
error ("The function " .. key .. " doesn't exiist in " .. newinst:getType(), 2) -- den deze...
end
end
Since you need to return a function (rather than evaluate a function) you can create a proxy for the aFunction and return that instead. Here's how it could work (with a bunch of code taken from the solution by Nicol Bolas):
local someBoolean = false
function doSomething(...) -- this is the function used in __index in a proxy table
someBoolean = true
-- Return a proxy function instead of aFunction
return function(...)
local rets = { aFunction(...) }
someBoolean = false
return table.unpack(rets)
end
end
You cannot execute code after a return statement. The correct answer is to call the function, catch the return values, set the variable, and then return the return values. For example:
local someBoolean = false
function doSomething(...) -- this is the function used in __index in a proxy table
someBoolean = true
local rets = { aFunction(...) } -- this is function that we can NOT alter
someBoolean = false
return table.unpack(rets)
end
In Lua, is it possible to know which function has called the current function.
For instance
function a()
get_calling_function() --Should print function b
end
function b()
a()
end
Is something like this possible?
Does the debug library have such functionality?
You could use debug.traceback():
function a()
print(debug.traceback())
end
function b()
a()
end
b()
which would print:
stack traceback:
./test.lua:45: in function 'a'
./test.lua:50: in function 'b'
./test.lua:53: in main chunk
[C]: in ?
you can use debug.sethook() to set up a hook that gets called each time certain special events happen in lua. it can be useful for things like this.
local debugInfo = { caller = nil, callee = nil }
function hook()
local info = debug.getinfo(2)
if info == nil then
debugInfo.callee = nil
return
end
-- we only want to watch lua function calls (not C functions)
if info.what ~= "Lua" then
debugInfo.callee = "C function"
return
end
debugInfo.caller = debugInfo.callee
debugInfo.callee = info.name
end
debug.sethook(hook, "c")
function caller1()
if debugInfo.caller ~= nil and debugInfo.callee ~= nil then
msg = debugInfo.callee.. " was called by ".. debugInfo.caller.. "!"
print(msg)
end
end
function caller2()
caller1()
end
caller2()
this prints 'caller1 was called from caller2!'
debug.sethook can handle 3 different characters in the second parameter so you can let it know when to notify you. 'c' means call your hook function any time a function is called in lua, 'r' means call your hook function every time a function returns in lua, and 'l' means call your hook function whenever lua processes a new line of code.
you could set this up to build your own custom stack trace if you really wanted to, and you could also use debug.getlocal() within your hook to even try to work out what arguments were passed to your called function.
edit for lhf. this is actually a much simpler way of doing what you're asking, if you don't need to track this and just need to know the context of how the function was called.
function caller1()
local current_func = debug.getinfo(1)
local calling_func = debug.getinfo(2)
print(current_func.name.. " was called by ".. calling_func.name.. "!")
end
function caller2()
caller1()
end