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<div>Hello,</div>
<div> </div>
<div>Has anyone thought about the possibility of adding return values from CMake functions? This would be a very useful language feature that the Trilinos CMake files would use everywhere.</div>
<div> </div>
<div>Here is an example use case. One problem with CMake is that it has very loose checking. For example, if I write:</div>
<div> </div>
<div> IF (MYVARABLE)</div>
<div> ...</div>
<div> ENDIF()</div>
<div> </div>
<div>Instead of what I meant:</div>
<div> </div>
<div> IF (MYVARIABLE)</div>
<div> ...</div>
<div> ENDIF()</div>
<div> </div>
<div>then my CMakeLists.txt file will not work correctly. What I have been doing is to instead write an ASSERT_DEFINED(...) macro and then use it as:</div>
<div> </div>
<div> ASSERT_DEFINED(MYVARIABLE)</div>
<div> IF (MYVARIABLE)</div>
<div> ...</div>
<div> ENDIF()</div>
<div> </div>
<div>Of course the problem with this is that I could misspell one of the uses as:</div>
<div> </div>
<div> ASSERT_DEFINED(MYVARIABLE)</div>
<div> IF (MYVARABLE)</div>
<div> ...</div>
<div> ENDIF()</div>
<div> </div>
<div>and I am back in the same situation. The problem is that I am duplicating the variable name. This is a fundamental software engineering issue that needs to be addressed in some way.</div>
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<div>What I would like to be able to write is a function like:</div>
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<div> FUNCTION(ASSERTDEF VARNAME)</div>
<div> IF(NOT DEFINED ${VARNAME})</div>
<div> MESSAGE(SEND_ERROR "Error, the variable ${VARNAME} is not defined!")</div>
<div> ENDIF()</div>
<div> RETURN(${VARNAME})</div>
<div> ENDFUNCTION()</div>
<div> </div>
<div>You could then use this function like:</div>
<div> </div>
<div> IF (${ASSERTDEF(MYVARIABLE)$)</div>
<div> ...</div>
<div> ENDIF()</div>
<div> </div>
<div>Then, if I misspelled the variable name as:</div>
<div> </div>
<div> IF (${ASSERTDEF(MYVARABLE)}$)</div>
<div> ...</div>
<div> ENDIF()</div>
<div> </div>
<div>I would get an error message and processing would stop immediately.</div>
<div> </div>
<div>Above, I assume that the syntax:</div>
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<div> ${SOMEFUNCTION(ARGS)}</div>
<div> </div>
<div>Is needed to get CMake to expect a return value from the function and then return it, just like it would return a variables value.</div>
<div> </div>
<div>How hard would it be to all return values from CMake functions in this way?</div>
<div> </div>
<div>Thanks,</div>
<div> </div>
<div>- Ross</div>
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