Question

I have some elisp files in a project that I want to byte compile and install with CMake. After compilation I want to have a target to install the .el and .elc files to a directory. What I have so far is

set(ELISP_SOURCES
  a.el.in
  b.el
  )

# Top level target to compile the elisp sources
add_custom_target(emacs_byte_compile ALL)

foreach(el ${ELISP_SOURCES})

  # Configure and copy the files
  get_filename_component(EL_NAME ${el} NAME_WE)
  configure_file(${el} ${CMAKE_CURRENT_BINARY_DIR}/${EL_NAME}.el)

  # Add command to compile the files
  add_custom_command(OUTPUT ${CMAKE_CURRENT_BINARY_DIR}/${EL_NAME}.elc
    COMMAND ${EMACS} ARGS -batch -f batch-byte-compile ${CMAKE_CURRENT_BINARY_DIR}/${EL_NAME}.el
    DEPENDS ${CMAKE_CURRENT_BINARY_DIR}/${EL_NAME}.el
    WORKING_DIRECTORY ${CMAKE_CURRENT_BINARY_DIR}
    )

  # Create the dependencies
  add_dependencies(emacs_byte_compile
    ${CMAKE_CURRENT_BINARY_DIR}/${EL_NAME}.el ${CMAKE_CURRENT_BINARY_DIR}/${EL_NAME}.elc
    )

  # Installation target
  install(FILES ${CMAKE_CURRENT_BINARY_DIR}/${EL_NAME}.el ${CMAKE_CURRENT_BINARY_DIR}/${EL_NAME}.elc
    RUNTIME DESTINATION ${ELISP_DIR}
    )

endforeach(el)

When I configure with cmake (or ccmake) and then run make, it doesn’t compile the .el files. It does however say that it finished building the target emacs_byte_compile. So I assume I have some misunderstanding as to how the dependencies work.

Answer 1

You need to create a top level target that consumes the output of the custom command you created. You can find some ideas here: http://www.cmake.org/Wiki/CMake_FAQ#How_can_I_generate_a_source_file_during_the_build.3F

The add_dependencies command is only useful for connecting top level cmake targets, so that line is not doing anything.

Something like this:

foreach(el ..)
  # collect output files into a list
  # create a custom command to run emacs to create the elc, 
  #input is .el output is .elc
endforeach()
add_custom_target(emacs_byte_compile DEPENDS ${ELC_LIST})