Support Multiple Catch

[BPScott]

Support for multiple catch types was added to PHP 7.1 as per https://wiki.php.net/rfc/multiple-catch.
php/php-src#1796 is the PR that merged this feature into php master.

This makes the following code valid in PHP 7.1:

try {
   // Some code...
} catch (ExceptionType1 | ExceptionType2 $e) {
   // Code to handle the exception
}

I'm new to this project (and parsers in general) but from what I can tell the grammar for the try statement should be updated to allow for multiple, pipe-separated qualified-name items.

I think the following grammar is correct:

try-statement:
  'try' compound-statement catch-clauses
  'try' compound-statement finally-clause
  'try' compound-statement catch-clauses finally-clause

catch-clauses:
  catch-clause
  catch-clauses catch-clause

catch-clause:
  'catch' '(' catch-name-list variable-name ')' compound-statement

catch-name-list:
  qualified-name
  catch-name-list '|' qualified-name

finally-clause:
  'finally' compound-statement

[nikic]

Yup, that grammar looks right. Committed together with some corresponding changes in the text.