arrays, composite types

I'm looking for an equivalent of my_composite_type[] for use as a
parameter of a pl/pgsql function. What do people use to dodge this
limitation?

Background: I have a few plpgsql functions that basically accept an
array of objects decomposed into arrays of the objects' attributes:

CREATE FUNCTION do_foo(int4, int4[], int4[], varchar[]) RETURNS int4 VOLATILE

which I'd like to convert to

CREATE FUNCTION do_foo(int4, myctype[]) RETURNS int4 VOLATILE

so that the functions only need recompilation when myctype changes.

myctype is

CREATE TYPE myctype AS (a int4, b int4, c varchar)

Ideally, what I'm looking for will work in plpgsql, but I'm ok with
writing a bit or two in C as long as it can be made short,
selfcontained, and bugfree (crashing PostgreSQL or wrong data would be
enough rope to hang myself on I'm afraid).

BTW, I don't see arrays of composite types in the TODO, and the ability
to specify composite types indirectly through schema.rel.attr%TYPE isn't
there either. Are these two features out of the question for some
reason?

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