Reference

substitute_top_level(var, val, mod, expr)

Takes a syntax object expr and substitutes every occurence of module var for val, only if the resulting object is actually present in module mod. The mod module should correspond with a lookup of val in the caller's namespace.

@compose module Name
    [@mixin Parents, ...]
    ...
end

Creates a new composable module Name. Structs inside this module are merged with those of the same name in Parents.

@for_each(M -> M.method(), lst::Vector{Symbol})

Calls method() for each module in lst that actually implements that method. Here lst should be a vector of symbols that are all in the current module's namespace.

@spec module *name*
    *body*...
end

Create a spec. The @spec macro itself doesn't perform any operations other than creating a module and storing its own AST as const *name*.AST.

This macro is only here for teaching purposes.