[bonzini]

Why not both? :-) While the architecture is more similar to CMake, Meson's language reminds me of SCons---but it is a custom DSL and not Python, which makes things less surprising. For example in SCons a single-element list can be replaced with with the element itself, but that is a feature of SCons's builtins: if you write custom Python code, you can have confusing results when you place a string in a place where you must use a list of strings.

Also SCons is Turing complete and this makes it a bit of a stretch to call the language declarative; Meson keeps simple loops but is not Turing complete and the maintainers are okay with plans/pull requests that make Meson even more declarative. In Meson generally "there is only one way to do it", in SCons much less so which is ironic given it uses Python as the language.