# Chapter 14 — load a single JSON config file as a one-row table.
#
# The standalone JSON loader picks up `config.json` and inserts
# the parsed value as a single row of `config(blob: value)`. Rules
# destructure it with subscript, iteration, and coercion — same
# toolkit as JSONL ingestion, just with one source row.

extensional config(blob: value).

app_name(N) :- config(C), N = as_string(C["name"]).

# Iterate the `features` object: project the names whose flag is
# the JSON boolean true. `as_boolean` returns SQL NULL on shape
# mismatch, and the `= true` test then drops those rows.
enabled_feature(F) :-
    config(C),
    object_entry(C["features"], F, Flag),
    as_boolean(Flag) = true.

# Walk the `endpoints` array and project (index, path) for each.
endpoint(I, Path) :-
    config(C),
    array_element(C["endpoints"], I, E),
    Path = as_string(E["path"]).

?- app_name(N).
?- enabled_feature(F).
?- endpoint(I, P).