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

Hello Corey,

About v18: Patch applies, make check ok, psql tap tests ok.


ISTM that contrary to the documentation "\elif something" is not evaluated 
in all cases, and the resulting code is harder to understand with a nested 
switch and condition structure:
  switch  default    read    if       switch

I wish (this is a personal taste) it could avoid switch-nesting on the 
very same value. It should also conform to the documentation.

If there is no compelling reason for the switch-nesting, I would suggest 
to move the read_boolean_expression before the swich, to deal with error 
immediately there, and then to have just one switch.

Alternatively if the structure must really be kept, then deal with errors 
in a first switch, read value *after* switch and deal with other errors 
there, then start a second switch, and adjust the documentation 
accordingly?
  switch    errors  read  if    errors  // no error  switch


Also, the %R documentation has single line marker '^' before not executed 
'@', but it is the reverse in the code.

-- 
Fabien.