[CMake] STRING(CONFIGURE ...) problem with too-early variable substitution

[Zachary Pincus]

Hi again folks,

I'm trying to use the CMake STRING(CONFIGURE ...) command.
For reference, this should 'configure' a string the way that  
CONFIGURE_FILE does to a file.

The general gist of what I want to do is something like

SET(to_configure "/path/to/@directory@")

and then in a macro:
SET(directory "frob")
STRING(CONFIGURE to_configure configured @ONLY)

to get the result that ${configured} contains "/path/to/frob".

Of course, this doesn't work, because CMake tries to substitute the  
variable @directory@ right when to_configure is set!

Is there any good way to get the literal '@...@' or '$ 
{...}' (excluding the quotes) into a CMake variable? If not, what use  
is STRING(CONFIGURE ...)?

I tried using SET(to_configure '@...@') which is the shell-style way  
of preventing variable substitution, but that didn't work at all. Not  
using quotes at all is a problem in cases when there need to be  
spaces in the string, and I'm not sure it would work in any case.

Right now, I work around this issue by using STRING(REPLACE ...)  
instead, but I do wonder what the right way to use STRING 
(CONFIGURE ...) is?