Automatically reindent lines filtered through formatprg

Question

I have following xml file:

<?xml version="1.0" encoding="UTF-8"?>
<graph id="G" edgedefault="undirected">
    <edge id="e6" source="n5" target="n4"> <data key="d1">1.1</data> <data key="d2">1.1</data> </edge>
</graph>

I have reconfigured formatprg for xml in ~/.vim/after/ftplugin/xml.vim:

setlocal formatprg=tidy\ -xml\ -quiet\ --indent\ auto\ --tidy-mark\ no\ --indent-spaces\ 2\ --vertical-space\ yes\ 

When I now press gqq on line 3, I get

<?xml version="1.0" encoding="UTF-8"?>
<graph id="G" edgedefault="undirected">
<edge id="e6" source="n5" target="n4">
  <data key="d1">1.1</data>
  <data key="d2">1.1</data>
</edge>
</graph>

I want to fix the indentation automatically.

My first try was :'[,']norm = which does not work as expected.

However, =at does.

Ideally, I want to extend gq<text object/motion> and gqq so re-indentation (=, indentexpr) is done on the newly formatted lines.

Answer 1

Linewise gqq with support for counts

I have come up with following solution for the linewise operator gqq by putting

nnoremap <buffer> gqq gqq$='[

into ~/.vim/after/ftplugin/xml.vim (the $ was important). Counts work already:

<?xml version="1.0" encoding="UTF-8"?>
<graph id="G" edgedefault="undirected">
    <edge id="e6" source="n5" target="n4"> <data key="d1">1.1</data> <data key="d2">1.1</data> </edge>
    <edge id="e7" source="n3" target="n4"> <data key="d1">1.1</data> <data key="d2">1.1</data> </edge>
</graph>

Again cursor on line 3 and then press 2gqq. The result is

<?xml version="1.0" encoding="UTF-8"?>
<graph id="G" edgedefault="undirected">
    <edge id="e6" source="n5" target="n4">
        <data key="d1">1.1</data>
        <data key="d2">1.1</data>
    </edge>
    <edge id="e7" source="n3" target="n4">
        <data key="d1">1.1</data>
        <data key="d2">1.1</data>
    </edge>
</graph>

Vim-operator-user re-mappings of gq<text object/motion> and {VISUAL}gq

Install the plugin vim-operator-user and put

map <buffer> gq <Plug>(operator-myformat)
call operator#user#define('myformat', 'Op_format_and_reindent')
function! Op_format_and_reindent(motion_wiseness)
  exe "normal! '[V']gq$='["
endfunction

into ~/.vim/after/ftplugin/xml.vim.

This should also work for other files with a 'formatprg' and the desire to reindent automatically afterwards.