Vim indentation for c++ templates?

Question

Does anyone have or know about vim plugin/macro/function that indents nicely c++ templates?

When I highlight template definition in vim .hpp/.h file and indent it with '=' I get something like this:

>     template <
>         class TFilter,
>               class TParser,
>               class TConsumer,
>               class TDataProcessor,
>               class TDataFeed,
>               class TSymbolMap
>                   >
>                   struct DataFeedTraits
>                   {
>                       typedef TFilter             Filter;
>                       typedef TParser<TSymbolMap> Parser;
>                       typedef TConsumer<Parser>   Consumer;
>                       typedef TDataProcessor<Filter,Consumer>  DataProcessor;
>                       typedef TDataFeed<Filter,DataProcessor,Parser,Ccnsumer> DataFeed;
>                   };

I think the cindent aligns the struct/class declaration with the closing bracket '>'. I would like to end up with something like this, or similar, exact formatting does not matter, as far as it is formatted:

template <
    class TFilter,
    class TParser,
    class TConsumer,
    class TDataProcessor,
    class TDataFeed,
    class TSymbolMap
    >
struct DataFeedTraits
{
    typedef TFilter             Filter;
    typedef TParser<TSymbolMap> Parser;
    typedef TConsumer<Parser>   Consumer;
    typedef TDataProcessor<Filter,Consumer> DataProcessor;
    typedef TDataFeed<Filter,DataProcessor,Parser,Ccnsumer> DataFeed;
};

Answer 1

My solution:

" Don't indent namespace and template
function! CppNoNamespaceAndTemplateIndent()
    let l:cline_num = line('.')
    let l:cline = getline(l:cline_num)
    let l:pline_num = prevnonblank(l:cline_num - 1)
    let l:pline = getline(l:pline_num)
    while l:pline =~# '\(^\s*{\s*\|^\s*//\|^\s*/\*\|\*/\s*$\)'
        let l:pline_num = prevnonblank(l:pline_num - 1)
        let l:pline = getline(l:pline_num)
    endwhile
    let l:retv = cindent('.')
    let l:pindent = indent(l:pline_num)
    if l:pline =~# '^\s*template\s*\s*$'
        let l:retv = l:pindent
    elseif l:pline =~# '\s*typename\s*.*,\s*$'
        let l:retv = l:pindent
    elseif l:cline =~# '^\s*>\s*$'
        let l:retv = l:pindent - &shiftwidth
    elseif l:pline =~# '\s*typename\s*.*>\s*$'
        let l:retv = l:pindent - &shiftwidth
    elseif l:pline =~# '^\s*namespace.*'
        let l:retv = 0
    endif
    return l:retv
endfunction

if has("autocmd")
    autocmd BufEnter *.{cc,cxx,cpp,h,hh,hpp,hxx} setlocal indentexpr=CppNoNamespaceAndTemplateIndent()
endif

Answer 2

You can use the identexpr option to specify indent by evaluating an expression (i.e. writing a vim script function). This function should accept a string -- the line -- and return the number of spaces to indent. This gives you the flexibility to return an indent level for this template condition, or fall-back to autoindent, smartindent or cindent in normal, C-like situations.

Here is an example that was created to handle the signals and slots extension of Qt. It demonstrates fall-back to the cindent function.