#!/usr/bin/env perl

# Execute shell commands and include their output in the current buffer.
#
# This is brittle and probably very subject to quoting problems, but in
# practice it's been a useful hack for local notes and technical writing.
#
# See also:
#
#   - filter-exec for formatted output including the original command
#
#   - filter-exec-stdin for a version that passes the contained block to
#     stdin of the executed command

use strict;
use warnings;
use 5.10.0;

my $text;
{
  # Line separator:
  local $/ = undef;
  $text = <>;
}

# HTML quote markers / commands:
$text =~ s{
  <!--[ ]exec-raw[ ](.*?)[ ]-->
  .*?
  <!--[ ]end[ ]-->
}{
  handle_block('<!-- ', $1, ' -->', '<!-- end -->');
}egsx;

# Vim/VimWiki-style markers:
$text =~ s/
  [{]{3}exec-raw[ ](.*?)$
  .*?
  [}]{3}
/
  handle_block('{{{', $1, '', '}}}');
/egmsx;

print $text;

sub handle_block {
  my ($start, $command, $command_end, $end) = @_;
  my $result = `$command`;
  return "${start}exec-raw ${command}${command_end}\n${result}${end}";
}

__DATA__
A self-test - use ,r in vim to check:

{{{exec-raw date
Thu 02 Apr 2020 11:49:22 AM MDT
}}}

<!-- exec-raw date -->
Thu 02 Apr 2020 11:49:22 AM MDT
<!-- end -->

<!-- exec-raw pwd -->
/home/brennen/notes
<!-- end -->

<!-- exec -->

    $ ls ~/bin/filter-exec-raw
    /home/brennen/bin/filter-exec-raw

<!-- end -->