How do you trigger the MouseButton1Down Event?

Let's say you wanted to trigger a mousebutton1Down for a tool? How would you trigger it? Like I don't believe it'd be this way:

Tool = script.Parent
Tool.MouseButton1Down:connect(function()
-- Whatever here lol
end)

It just doesn't look right.

This might help you,

http://wiki.roblox.com/index.php?title=Weapons

Tool = script.Parent

function functionname() -- functionname is the name of the function but it could be whatever you want
-- whatever here
end

Tool.MouseButton1Down:connect(functionname) 

I could be wrong but i think it is like this!