[development] PHP input format -> syntax checking

[Tadej Baša]

Hi,
as you know, there is no way to recover from syntax errors in PHP code a 
  user submits (either as nodes or for example in custom block 
visibility settings). I'm trying to figure out, if it would be possible 
to send the code to drupal_eval with javascript and prevent form 
submission if an error is returned.
What do you think?

-Tadej