Best/Shortest way to join a list in CMake

Question

What is the best way to join a list in CMake into a string?

By joining I mean convert SET(somelist \"a\" \"b\" \"c\\;c\") to \"a:b:c;c\" where the glue string (\":\") i

Answer 1

Usually this task is solved with simple string REPLACE command. You can find a number of such replaces in scripts coming with cmake. But if you really need to care about semicolons inside you values, then you can use the following code:

function(JOIN VALUES GLUE OUTPUT)
  string (REGEX REPLACE "([^\\]|^);" "\\1${GLUE}" _TMP_STR "${VALUES}")
  string (REGEX REPLACE "[\\](.)" "\\1" _TMP_STR "${_TMP_STR}") #fixes escaping
  set (${OUTPUT} "${_TMP_STR}" PARENT_SCOPE)
endfunction()

SET( letters "" "\;a" b c "d\;d" )
JOIN("${letters}" ":" output)
MESSAGE("${output}") # :;a:b:c:d;d