How can I avoid warnings about unused variables?

Question

I have some code in my ~/.vimrc that (simplified) looks like this:

function! SomeAppendFunction()
    let failed = append(0, ["Some header text"])
endfunction
command SomeAppendFunction :call SomeAppendFunction()

The intent is to provide a command that prepends some fixed text to any file I wish. I don't really care too much about handling errors from the append() function.

When I run Syntastic over this, which uses vimlint to check it, it quite rightly warns that I'm not using the return variable failed:

/Users/xyz/.vimrc|255 col 9 warning| [EVL102] unused variable `l:failed`

However, if I remove the let failed = from the line inside the function, so it looks like this:

function! SomeAppendFunction()
    append(0, ["Some header text"])
endfunction
command SomeAppendFunction :call SomeAppendFunction()

... I instead now see: ...

line  301:
E126: Missing :endfunction

... when I start vim.

How can I avoid the warning about the unused variable, but also have a syntactically correct function?

Answer 1

append() is a function and no command. As such, it must be called using the :call command. So use :call append(). Second, if you want to ignore errors, you can wrap the whole command into a try...catch...endtry statement like this:

try
   call append()   " could fail for whatever reason
catch
   " no-op
endtry