[Cmake] Regular expression ++ nesting problem

[Brad King]

David Svoboda wrote:
> On Thu, 26 Feb 2004, Brad King wrote:
> 
> 
>>David Svoboda wrote:
>>
>>>Hello,
>>>
>>>I used the following construction:
>>>
>>>IF ("${MY_STRING_PATH}" MATCHES "${CHOSEN_PATH}.*")
>>>	...
>>>
>>>
>>>to test, whether CHOSEN_PATH is included in MY_STRING_PATH. Everything had
>>>worked well until I tried SET(CHOSEN_PATH /usr/local/packages/g++-3.0).
>>>Here the variable CHOSEN_PATH contains the "+" sign (twice) and causes
>>>errors in CMake:
>>>
>>>
>>>***
>>>-- Check for working C compiler: gcc -- works
>>>-- Check for working CXX compiler: g++-3.0 -- works
>>>RegularExpression::compile(): Nested *?+.
>>>RegularExpression::compile(): Error in compile.
>>>RegularExpression::compile(): Nested *?+.
>>>RegularExpression::compile(): Error in compile.
>>>-- Configuring done
>>>-- Generating done
>>>***
>>>
>>>
>>>I tried some "\" or "'" signs, but it did not work. Could anybody help me?
>>
>>The "MATCHES" expression in an IF statement should always be written by
>>hand due to the reason you just encountered.  If you have a string you
>>want to compare, use the "STRING" command.  See "cmake --help STRING"
>>for details.
>>
>>-Brad
>>
> 
> 
> I looked through the STRING(...) help. The most suitable seems the command
> 
> 	STRING(COMPARE LESS <string1> <string2> <output variable>)
> 
> But this command compares the length of the strings - not the string
> themselves. Hence I do not know, how to test wheter the string

It does compare the strings themselves, but it is not intended to 
identify substrings.  Take a look at Source/cmStringCommand.cxx if you 
would like to contribute more advanced string operations.

> 	/usr/local/packages/omniorb-4.0.1-g++-3.0
> 
> is substring of
> 
> 	/usr/local/packages/omniorb-4.0.1-g++-3.0/bin/omniidl
> 
> for example. Or more precisely, if the directory
> 
> 	/usr/local/packages/omniorb-4.0.1-g++-3.0
> 
> contains subdirectory or application
> 
> 	/usr/local/packages/omniorb-4.0.1-g++-3.0/bin/omniidl

In that case you'll have to write a loaded command or find another way 
to implement this logic.  You could try going back to the MATCHES 
approach, but first use STRING(REGEX REPLACE ...) to escape the special 
characters.  What is your ultimate goal for this test?

-Brad