find_program(JAVACC_EXECUTABLE NAMES javacc javaCC Javacc JavaCC javacc.bat DOC "path to the javacc executable")
mark_as_advanced(JAVACC_EXECUTABLE)
set(JAVACC_FOUND 0)
if(JAVACC_EXECUTABLE)
  execute_process(
      COMMAND "${JAVACC_EXECUTABLE}" -version
      OUTPUT_VARIABLE JAVACC_TEMP_VERSION
  )
  string(REGEX MATCH ".* ([0-9]+(\\.[0-9]+)+) .*" JAVACC_TEMP_VERSION2_UNUSED "${JAVACC_TEMP_VERSION}")
  if(CMAKE_MATCH_1)
    set(JAVACC_FOUND 1)
    set(JAVACC_VERSION ${CMAKE_MATCH_1})
  else()
    string(REGEX MATCH "([0-9]+(\\.[0-9]+)+)" JAVACC_TEMP_VERSION3_UNUSED "${JAVACC_TEMP_VERSION}")
    if(CMAKE_MATCH_1)
      set(JAVACC_FOUND 1)
      set(JAVACC_VERSION ${CMAKE_MATCH_1})
    endif()
  endif()
endif()
if(JAVACC_FOUND)
  message(STATUS "The javacc executable: ${JAVACC_EXECUTABLE} (found version \"${JAVACC_VERSION}\")")
else()
  message(STATUS "The javacc executable not found, using existing files")
endif()