Question

I like to write code using the ternary ?: operator like this:

std::string result = input.empty() ? createNewItem()
                                   : processInput( input );

How can I configure vim so that when pressing Return after having typed createNewItem() indents the next line so that the cursor is in the same column as the last ? so that I can just continue typing : processInput( input );?

I tried looking at the cinoptions-values setting but I didn’t see anything relevant.

Answer 1

Inspired by a roughly similiar question I exercised my vimscript-fu and created a little script to do this job:

if (!exists("*CppIndentDepth"))
    function CppIndentDepth()
        let lineno = v:lnum
        let lastQuestionMark = match(getline(lineno-1), "?[^?]*")
        if lastQuestionMark != -1
            return lastQuestionMark
        endif
        return cindent(lineno)
    endfunction
endif

set indentexpr=CppIndentDepth()

I saved this file as vimfiles/indent/after/cpp.vim and added filetype indent on to my .vimrc to toggle loading of indentation plugins. It seems to work good enough!