NEWS.md

v0.7.0

• FunctionTerm rework (#183)

  • FunctionTerm{F,Args} now stores the called function, the original expression, and the arguments (wrapped in Term/ConstantTerms). Package maintainers that rely on FunctionTerm representations to implement special syntax will need to substantially update that existing code. This may be as simple as defining a run-time method for my_fun that takes in AbstractTerms and returns MyTermType with an accompanying method for apply_schema(::FunctionTerm{typeof(my_fun)}, ... that recursively applies the schema to the captured arguments and calls the run-time method:

    my_fun(args::AbstractTerm...) = MyTermType(args...)
    
    function apply_schema(t::FunctionTerm{typeof(my_fun)}, schema, Ctx)
        args = apply_schema.(t.args, Ref(schema), Ref(Ctx))
        return t.f(args...)
    end

    However, if the @formula syntax (i.e., & for interaction, + for union, etc.) should apply within the call to my_fun, then care needs to be taken to un-protect any nested calls as necessary (although this is only likely to be a concern if the special syntax occurs as a child of another, non-special call). The above recommendation may still Just Work™ but some thorough testing is recommended.

  • It is now possible (although not exactly convenient) to construct FunctionTerms at run-time (i.e., outside of a @formula macro). See the tests for an example of how this might be accomplished in practice.

  • Special syntax is introduced to protect function calls from the usual @formula interpretation (i.e., to treat + as addition, use protect(a + b)) and unprotect calls, switching back to interpreting them as @formula specials (i.e., to take the logarithm of an interaction term, use log(unprotect(a & b))).

• Various minor but breaking changes in contrast coding: (#273)

  • ContrastsMatrix can use arbitrary AbstractMatrixes to store the actual contrasts matrix.

  • The number and order of type parameters on ContrastsMatrix{C,M,T,U} have changed (from ContrastsMatrix{C,T,U}), with the addition of the second type parameter M capturing the type of the contrasts matrix. This is unlikely to affect users but package developers must update anywhere they are specializing on T or U (which capture the eltype of the term names and levels, respectively).

  • All AbstractContrasts now have keyword argument constructors.

  • When constructing HypothesisCoding instances, the labels= and levels= kwargs are now mandatory.

  • ContrastsCoding is no longer exported (previously, a warning was issue that this export is deprecated and is discouraged).

  • The un-used base= kwarg for SeqDiffCoding has been removed (previously was a deprecation warning).