Workaround for inlined SQL function dispatch in PostgreSQL - postgresql

Question

Goal
I'm trying to make PostgreSQL do something like function dispatch, but I'm open to any other solution for the problem that lets me keep the function I'm calling a SQL function (versus PL/PGSQL) because I want it to be inlined.
Suppose I have two functions like:
create or replace function is_in_view_one(p people) returns boolean as $$
select p.state = ANY(ARRAY['TX', 'NY', 'CA'])
$$ language sql strict stable;
And:
create or replace function is_in_view_two(p people) returns boolean as $$
select p.state = ANY(ARRAY['NV', 'FL', 'MT'])
$$ language sql strict stable;
I want to be able to write some code, or adapt the above functions, so I can write:
select count(*)
from people
where is_in_view(people, 'one');
And I want is_in_view to be fully inline-able according to these criteria: https://wiki.postgresql.org/wiki/Inlining_of_SQL_functions'
Attempted Solution via Domains
I've tried to set up a solution using domains as function identifiers, and although it doesn't work, I think someone more knowledgeable about PostgreSQL types, casts, and function identification might know how to hack it.
I tried to do:
create domain view_one_id as uuid check (value = 'ed744964-6561-11eb-878e-c7ad77d3260a');
create domain view_two_id as uuid check (value = 'fa9fe0f8-6561-11eb-878e-c79c81b46d0c');
create or replace function say_n(v view_one_id) returns integer as $$
select 1
$$ language sql strict;
create or replace function say_n(v view_two_id) returns integer as $$
select 2
$$ language sql strict;
Hoping that I could then do:
select say_n('ed744964-6561-11eb-878e-c7ad77d3260a') # 1
select say_n('fa9fe0f8-6561-11eb-878e-c79c81b46d0c') # 2
But instead I get:
=# select say_n('fa9fe0f8-6561-11eb-878e-c79c81b46d0c');
ERROR: function say_n(unknown) is not unique
LINE 1: select say_n('fa9fe0f8-6561-11eb-878e-c79c81b46d0c');
^
HINT: Could not choose a best candidate function. You might need to add explicit type casts.
I can do:
=# select say_n('fa9fe0f8-6561-11eb-878e-c79c81b46d0c'::view_two_id);
say_n
-------
2
(1 row)
But in order to integrate with external tooling that knows how to call functions and only call functions (not also supply a variable type cast) I'm holding out hope for a solution that doesn't require modifications to this external tooling.
Happy to entertain alternatives! I feel like this solution might be possible by fiddling with the CAST or something, however.

Answer 1

What about using CASE:
select p.state = ANY (CASE WHEN $2 = 'one'
THEN ARRAY['TX', 'NY', 'CA']
ELSE ARRAY['NV', 'FL', 'MT']
END)
But if you want efficiency, you would be better off with the two functions, because the above cannot use an index.