Re: [PHP] Re: poll: howto do informative error handling without the fatalities

On Wed, Feb 10, 2010 at 3:04 AM, Paul M Foster <[email protected]> wrote:
> $d = funcD($q);
> // tests if necessary
> $c = funcC($p);
> // tests if necessary
> $b = funcB($c);
> // tests if necessary
> $r = funcA($b, $d);
>

You're right.
I knew when i was posting my last reply yesterday that i had made
things probably too complicated.

But after sleeping and a look at real code which is to work with my
improved-err-handling, i've come up with a new construct, that i think
will fit the bill for now.

I'm going to use the "result meta-array" instead of "plain result
values", because that
- completely equalizes the syntax for detecting bad results, and
prevents doing a lookup with a function to a value that is also the
"bad-result" return value for the lookup function.
- is much easier to read, than checking what the "bad-result" value is
for a lookup function.
- allows me to redirect the error info from a called function inside
the calling function
- allows infinite expansion of (meta-)communication between calling
and called functions.

So while i'm dumping the funcA (defaults($onError_pValue), $p) crap,
i'm retaining most of the other ideas in my previous post to this
thread.

the calling function does this, inside 3x foreach:
........
					// if not done yet, resolve the fields for this table=>hit that
require looking-up
					if (!$sqls[$tableName]['hasPreInserts']) {
						foreach ($tableCmd['preInsertFields'] as $fieldName=>$fieldLookupCmd) {
							$r = maintenance__lookupPreInserts ($wm, $fieldLookupCmd);
							if (!good($r)) {
								$tableCmd['invalidPreInserts'] = true;
							} else {
								$sqls[$tableName]['preInserts'][$fieldName] = result($r);
							}
						}
					}
					
					if (!array_key_exists('invalidPreInserts', $tableCmd)) {
					// add the fields for this table for this hit:
.........


and the helper functions:

function maintenance__lookupPreInserts (&$wm, $fieldLookupCmd) {
  startErrorContext(); // to catch php E_NOTICE, E_WARNING, etc
	$flcp = explode ('::', $fieldLookupCmd);
	if (count($flcp)!=3) {
		return badResult(E_USER_ERROR, array(
			'msg' => 'Need 3 counts of \'::\'',
			'vars' => array (0=>array('$fieldLookupCmd', $fieldLookupCmd))
		));
  }	
	
	$section = $flcp[0];

	$searchInSection = array();
	$criteria = explode (',,', $flcp[1]);
	foreach ($criteria as $idx1 => $criterium) {
		$cs = explode('===',$flcp[1]);
		if (count($cs)!=2) return badResult (E_USER_ERROR, array(
				'msg' =>
					'Any criterium (after first "::", between ",,") needs to be like
this:'."\n".
					'fieldName===searchValue',
				'vars' => array (0=>array('$fieldLookupCmd', $fieldLookupCmd))
		));
		$searchInSection = array_merge ($searchInSection, array(
			$cs[0] => $cs[1]
		));
	}
	
	$pathInSection = explode(',,', $flcp[2]);
	
  foreach ($wm[$section] as $idx => $fields) {
    $gotIt = true;
    foreach ($searchInSection as $fn => $fv) {
      if ($fields[$fn]!=$fv) {
				$gotIt = false;
				break;
      }
    }
    if ($gotIt) {
      return chase ($wm[$section], $pathInSection);
    }
  }
}


function chase ($arr, $indexes) {
  startErrorContext();
  $r = $arr;
  foreach ($indexes as $idx) {
    if (is_array($r)) {
      $r = $r[$idx];
    } else {
			return badResult (E_USER_ERROR, array(
				'msg' => 'Could not walk the full tree',
				'vars' => array(
					0=>array('$arr', $arr),
					1=>array('$indexes', $indexes)
				)
			));
    }
  }
  return goodResult($r);
}