NERD_snippets.vim

let s:Marker = {}
let s:Marker.revlookup = {}
function! s:Marker.addRevlookup(lnum, index, istab)
    " get current list of tabstops per line
    if !exists('s:Marker.revlookup[a:lnum]')
        if a:istab
            let lookupList = {'tab': [a:index], 'ph': []}
        else
            let lookupList = {'tab': [], 'ph': [a:index]}
        endif

        let s:Marker.revlookup[a:lnum] = lookupList
    else
        if a:istab
            key = 'tab'
        else
            key = 'ph'
        endif
        let tabList = s:Marker.revlookup[a:lnum][key]
        let s:Marker.revlookup[a:lnum][key] = add(tabList, a:index)
    endif
endfunction