In a previous question I asked how to add a "Save as" button to the toolbar:
and got a great answer:
(tool-bar-add-item-from-menu 'write-file "save" nil :label "Save As")
I then asked "What does the
nil do?" and got a very extensive answer as to how the
nil works, ie a very complex explanation of how all the code works.
I do appreciate the time that the person took to explain this very extensive answer, but this totally overloaded me, since I do not understand emacs programming.
For this reason, I have never added a
Save as button to the toolbar, because I dont know what the
But it would save me a great deal of time if I had a
Save as button.
I maybe did not ask properly last time, I did not explain what I was looking for.
So I would like to ask again, and I will try to rephrase my question:
What does the
nil as second argument do? Not knowing what it does, I am concerned eg does it save the file in a different format? Or does bypass some part of the saving-file routine?
I am concerned this
nil negatively affects how a file is saved. I just want to feel confident that if I use the above
Save as command, that it does not have a risk of eg file corruption.
Or of course, maybe
nil does not in any way change how a file is saved.
I guess for me it just boils down to "Is using nil as the second argument safe?"
I use emacs all the time for very important files, and don't feel comfortable adding a
Save as button if I don't know fully what the command does.
Please note that to me, "what"
nil does is very different to "how it works" which is what was explained to me last time, and completely overloaded me, I could not understand this previous answer at all.
I am just asking for a brief answer like eg:
Yes using the
nil is safe (or not), and (eg)
nil is just a dummy parameter in the command to satisfy the requirement for parameter in this command, and does not change how the file is saved at all.
But not what I made up above :) but instead the real answer :)