[CMake] Weird if nesting problem

[Brandon J. Van Every]

James Bigler wrote:
>
>
>   FIND_PROGRAM(PARSER_EXECUTABLE
>     NAMES my_parser
>     PATHS ${PARSER_DIR} )
>
>   IF(EXISTS ${PARSER_EXECUTABLE})
>     SET(PARSERS_FOUND 1)
>   ELSE(EXISTS ${PARSER_EXECUTABLE})
>     SET(PARSERS_FOUND 0)
>   ENDIF(EXISTS ${PARSER_EXECUTABLE})
>
>  CMake Error: Error in cmake code at
>  /tmp/bigler/manta/trunk/src/CMake/FindParsers.cmake:20:
>  IF had incorrect arguments: EXISTS ${BISON_EXECUTABLE} (Unknown 
> arguments specified).
>  Current CMake stack:
>
> Is this a bug, or am I doing something wrong.  I would expect that 
> nothing in the else block to be evaluated if the if statement were true. 

Try IF(${PARSER_EXECUTABLE}).
A FIND_PROGRAM always sets a variable to -NOTFOUND when it doesn't find 
anything.  This is equivalent to FALSE.

Now having said that, I'd expect EXISTS to work.  But I'm a little tired 
to go over your program behavior.  The general drill with things like 
this, is to isolate the offending code snippet down to a trivial 
reproducer.  Your current snipped is almost but-not-quite trivial.  I 
note the docs say, "[EXISTS] behavior is well-defined only for full 
paths."  Is PARSER_EXECUTABLE in fact a full path?

BTW, given the -NOTFOUND output, seems like PARSERS_FOUND is a redundant 
variable.


Cheers,
Brandon Van Every