<?php
use Symfony\Component\Yaml\Yaml;

function render_php($file) {
  ob_start();
  #include __DIR__ . '/' . $file;
  include $file;
  $html = ob_get_clean();
  $meta = [];

  # Split off head matter
  #
  # this pattern uses the 'ms' modifier to treat multiline strings as a
  # single string, and let '\s', '.' etc treat newlines as whitespace
  # I match an _optional_ HTML ( '<!-- nnnn -->') comment if we want to wrap
  # the headmatter in a comment.
  #
  # The headmatter is delimited by either '----' or '++++' as per
  # Markdown/yaml standards.
  # Technical note that '+' is a regex character so \+{3,} instead of ++++
  if (preg_match('/^(<!--\s*)?(-{3,}|\+{3,})\s*(.*?)(-{3,}|\+{3,})\s*(-->)?\s*(.*)/ms',$html, $parts) === 1) {
     $html = $parts[6];
     $meta = array_merge($meta,Yaml::parse($parts[3]));
  }

  return [
     'html' => $html,
     'meta' => $meta,
  ];
}