Discussing accessibility for xcpp header files for lite

[anutosh491]

Hey @SylvainCorlay,

Currently for lite, after the install step we have this

-- Install configuration: "Release"
-- Installing: /Users/runner/micromamba/envs/xeus-cpp-wasm-host/share/xeus-cpp/tagfiles
-- Installing: /Users/runner/micromamba/envs/xeus-cpp-wasm-host/share/xeus-cpp/tagfiles/cppreference-doxygen-web.tag
-- Installing: /Users/runner/micromamba/envs/xeus-cpp-wasm-host/etc/xeus-cpp/tags.d
-- Installing: /Users/runner/micromamba/envs/xeus-cpp-wasm-host/etc/xeus-cpp/tags.d/stl.json
-- Installing: /Users/runner/micromamba/envs/xeus-cpp-wasm-host/share/jupyter/kernels
-- Installing: /Users/runner/micromamba/envs/xeus-cpp-wasm-host/share/jupyter/kernels/xcpp23
..........
-- Installing: /Users/runner/micromamba/envs/xeus-cpp-wasm-host/lib/cmake/xeus-cpp/xeus-cppConfig.cmake
-- Installing: /Users/runner/micromamba/envs/xeus-cpp-wasm-host/lib/cmake/xeus-cpp/xeus-cppConfigVersion.cmake
-- Installing: /Users/runner/micromamba/envs/xeus-cpp-wasm-host/bin/xcpp.js
-- Installing: /Users/runner/micromamba/envs/xeus-cpp-wasm-host/bin/xcpp.wasm
-- Installing: /Users/runner/micromamba/envs/xeus-cpp-wasm-host/bin/xcpp.data

So currently how we deal with xcpp/xdisplay.hpp and xcpp/xmime.hpp is this

xeus-cpp/CMakeLists.txt

Lines 385 to 392 in 97daaeb

	if (EMSCRIPTEN)
	execute_process(COMMAND ${CMAKE_COMMAND} -E make_directory ${SYSROOT_PATH}/include/xcpp)
	message(STATUS "Moving headers to ${SYSROOT_PATH}/include/xcpp")
	foreach(header ${XCPP_HEADERS})
	file(COPY ${header} DESTINATION ${SYSROOT_PATH}/include/xcpp)
	endforeach()
	else ()

So we take these headers, move them into sysroot/include/xcpp (and we load sysroot below)

xeus-cpp/CMakeLists.txt

Lines 438 to 440 in 97daaeb

	target_link_options(xcpp
	PUBLIC "SHELL: -s USE_SDL=2"
	PUBLIC "SHELL: --preload-file ${SYSROOT_PATH}/include@/include"

These end up in xcpp.data and when the .data file is loaded at runtime we can access the xdisplay header.

Am I not sure this should be the natural way for us to access this in lite.

1. Why don't we install it in Prefix/include/xcpp/**
2. And let empack do the rest of the job ?

[anutosh491]

I think xcpp.data should only and only be responsible for stander headers + clang headers. Any header coming from a third party lib or xcpp should just be done through empack I'd say. What do you think ?

[SylvainCorlay]

Why don't we install it in Prefix/include/xcpp/**

My intuition is that we should use Prefix install as much as possible. For third party libraries definitely. Maybe xcpp is in the gray area since it is included with the kerel. 🤷 .Then xcpp.data probably is not a great name.