Description:
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The (extremely useful) php.net/$keyword redirect currently doesn't support the array of pre-defined constants available within PHP. This is an extra problem because the manual search typically doesn't return relevant results for many of them: as an example, try <http://php.net/PHP_EOL> -- the right place to go would be <http://php.net/reserved.constants>, but that's not in the list.

I've concocted a patch for error.php to add support for the "core predefined constants" and the magic constants (including __NAMESPACE__, since it looks like we'll be getting that one soon enough), and it's at <http://www.adamharvey.name/stuff/error-constants.diff>. Hard-coding the constants into the manual page moves array probably isn't the best approach, but there's going to need to be an evil-looking list somewhere, I guess.

This patch doesn't address the longer list of "standard predefined constants", but it's a start. If the approach is acceptable (or a better one is recommended), I'll look at cooking up a patch for those as well.