On Fri, Feb 21, 2014 at 16:17:37 -0500, Matthew Woehlke wrote:
> Even without a branch, I'll risk stating that requiring 'if(FOO)' to
> become 'if(${FOO})' is not likely to go over well :-). (If nothing
> else, I'll go ahead and object to such a change.) Probably implicit
> expansion should be allowed anywhere the user doesn't think of the
> arguments as strings, e.g. if(LESS), if(VERSION_LESS), etc., i.e.
> everything *except* the string and regex flavors.
>From the if() docs, here's a grouping of what various predicates expect
along with my vote on whether it would make sense to do the implicit
dereference:
<varname>
DEFINED
Variable name
COMMAND
POLICY
TARGET
CMake object-names
EXISTS
IS_NEWER_THAN
IS_DIRECTORY
IS_SYMLINK
IS_ABSOLUTE
Paths
LESS
GREATER
EQUALS
Numbers
MATCHES
STRLESS
STRGREATER
STREQUAL
Strings (even if the right side of MATCHES is interpreted)
VERSION_LESS
VERSION_EQUAL
VERSION_GREATER
Version strings
Other than <varname>, I don't really see a huge burden to not allowing
implicit dereferencing and it is more consistent at that point. In fact,
I'd be willing to say in <varname> that we *only* support implicit
dereference, but it may be too hard to detect:
if (${var})
and actually help users to fix such cases.
--Ben
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