wierd AND condition evaluation for plpgsql

Hi,

I just noticed plpgsql evaluates all AND'ed conditions even if the first
one fails. Example:

elsif TG_OP = ''UPDATE'' and old.type_reponse = ''abandon''

This will break stuff if the trigger is used on INSERT as
"old.type_reponse" will be substituted and return an error.

Shouldn't plpgsql shortcut AND conditions when a previous one fails, as
perl does?

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