imap <silent><expr><Space> <SID>SpaceExpand()
imap <silent><expr><Tab> <SID>TabExpandOrJump()
smap <silent><expr><Tab> <SID>TabExpandOrJump()
imap <silent><expr><S-Tab> pumvisible() ? "\<C-p>" : "\<S-Tab>"
imap <silent><expr><Up> pumvisible() ? "\<C-p>" : "\<Up>"
imap <silent><expr><Down> pumvisible() ? "\<C-n>" : "\<Down>"
imap <silent><expr><Return> pumvisible() ? deoplete#close_popup() : "\<CR>"

function! <SID>IsCommentOrString(line, col) abort
    return synIDattr(synID(a:line, a:col, 0), 'name') !~ 'omment\|string' ? 1 : 0
endfunction

function! <SID>TabExpandOrJump() abort
    if pumvisible()
        return "\<C-n>"
    elseif synIDattr(synID(line('.'), col('.'), 0), 'name') !~ 'omment\|string'
                \ && neosnippet#expandable_or_jumpable()
        return neosnippet#mappings#expand_impl()
    endif
    return "\<Tab>"
endfunction

function! <SID>SpaceExpand() abort
    if <SID>IsCommentOrString(line('.'), col('.')) && neosnippet#expandable()
        return neosnippet#mappings#expand_impl()
    endif
    return "\<Space>"
endfunction