Re: \if, \elseif, \else, \endif (was Re: [HACKERS] PSQL commands:\quit_if, \quit_unless)

Hello Daniel,

> A comment about control flow and variables: in branches that are not 
> taken, variables are expanded nonetheless, in a way that can be 
> surprising. Case in point:
>
> \set var 'ab''cd'
> -- select :var;
> \if false
>  select :var ;
> \else
>  select 1;
> \endif
>
> To avoid that kind of trouble, would it make sense not to expand
> variables in untaken branches?

Hmmm. This case is somehow contrived (for a string, :'var' could be used, 
in which case escaping would avoid the hazard), but I think that what you 
suggest is a better behavior, if easy to implement.

-- 
Fabien.