Project structure discovery with Vim & NERDTree

TreeFind.vim

""
" Return project's root directory
"
" This function is used to return current projects root directory, as 
" determined by GIT or SVN, without changing vim's cwd.
"
" @param string a:1 A comma seperated list of files or directories, the 
" presence of which can be used to identify the root directory of a project.
"
function! UmkaDK#GetProjectRoot(...)
    let l:root_markers = a:0 > 0 ? a:1 : 
                \ 'Vagrant, Makefile, Makefile.PL, Build.PL, composer.json, Gemfile'
    let l:parent = expand("%:p:h")

    if executable('git')
        let l:git_root = system('cd ' . l:parent . ' && git rev-parse --show-toplevel 2>/dev/null')
        if !v:shell_error
            return substitute(l:git_root, '\(\n\|\s\)*$', '', '')
        endif
    endif

    if executable('svn')
        let l:label = 'Working Copy Root Path: '
        let l:svn_root = system('cd ' . l:parent . ' && svn info 2>/dev/null | grep "'. l:label . '"')
        if !v:shell_error
            let l:svn_root = strpart(l:svn_root, strlen(l:label))
            return substitute(l:svn_root, '\(\n\|\s\)*$', '', '')
        endif
    endif

    if !empty(l:root_markers)
        let l:parent_paths = [ l:parent ]
        while l:parent_paths[-1] != '/'
            call add(l:parent_paths, fnamemodify(l:parent_paths[-1], ':h'))
        endwhile

        let l:root_markers = substitute(l:root_markers, '^\s*\(.\{-}\)\s*$', '\1', '')
        let l:root_markers = '{' . join(split(l:root_markers, '\v\s*,\s*'), ',') . '}'

        let l:markers = globpath(join(l:parent_paths, ','), l:root_markers, 0, 1)
        if !empty(l:markers)
            let l:modifier = isdirectory(l:markers[0]) ? ':h:h' : ':h'
            return fnamemodify(l:markers[0], l:modifier)
        endif
    endif
endfunction

""
" Open NERDTree in a given directory
"
" This function is used to open NERDTree in a given directory and highlight
" current file within in directory's structure.
"
function! UmkaDK#NERDTreeFind()
    let l:path = expand("%:p:h")
    if !exists(":NERDTreeFind")
        return 0
    endif
    if !exists('b:project_root') || l:path !~ '^' . b:project_root
        let l:project_root = UmkaDK#GetProjectRoot()
        if !empty(b:project_root)
            let b:project_root = l:project_root
            exec 'NERDTreeToggle ' . b:project_root
            exec 'NERDTreeClose'
        endif
    endif
    if (!exists('b:project_root') && isdirectory(l:path)) || (b:project_root ==? l:path)
        exec 'NERDTreeToggle ' . b:project_root
    else
        exec 'NERDTreeFind'
    endif
endfunction

command! TreeFind call UmkaDK#NERDTreeFind()
nmap <silent> <Leader>wd :call UmkaDK#NERDTreeFind<CR>