Vim: sort al use statements inside a php file - php

Question

I'll like to learn how to select all lines that starts with use, inside current php file, and then sort them. Until now: I've worked with :sort command. Also, ... I've remapped sort command:
map <Leader>s :sort<CR>
But I'll like to create a complex function that select all use statements inside a php file, and after that, that sort all that lines.
I know how to sort. But I have no idea of what is the way to select some arbitrary group of strings with VimL
function! SortUseStatements()
let g:select='/^use .*$<CR>V' !?!?!?!?!?!?!?!?!?
exec g:select
endfunction
map <F2> :call SortUseStatements()<CR>
I know that I want to execute commands like:
go to the beginning of current file
sarch first ^use .*;$ statement
start selection
go to the end of current file
sarch last ^use .*;$ statement
and finally, run :sort

Answer 1

This can be neatly done with :help cmdline-ranges.
You want the search to start at the beginning of the file, so your initial address is 0 (to start before the first line). Then, search for the first line beginning with use. When separated with ; the cursor position will be set to that line before interpreting the next line specifier. Then, you need to navigate to the last of the use statements (starting from the first use line, so again separated by ;). I first choose an easy way that searches for an empty line, and then takes the previous one. With :print, you can check that the range is fine before replacing the command with :sort:
:0;/^use /;/^$/-1 print
If there's no empty line after the use block, you have to use a more complex pattern for any line not starting with use:
:0;/^use /;/^\(use \)\#!/-1 print
Alternatives
For anything more complex, a single :range probably won't do. I would then determine the start and end line numbers separately, using let lnum = search(...) with appropriate patterns. Then you can insert the numbers into an Ex command via :execute startLnum . ',' . endLnum . 'sort'