semver-ord.sql

CREATE OR REPLACE FUNCTION semver_ord(num varchar) RETURNS jsonb AS $$
DECLARE
    max_prerelease_parts constant int := 30;
    match_result text[] := regexp_match(num, '^(\d+).(\d+).(\d+)(?:-([0-9A-Za-z\-.]+))?');
    prerelease jsonb;
    prerelease_part text;
    i int := 0;
BEGIN
    IF match_result[4] IS NULL THEN
        -- A JSONB object has higher precedence than an array and versions without
        -- prerelease specifiers should have higher precedence too
        prerelease := json_build_object();
    ELSE
        -- Fill `prerelease` array with `null` values.
        -- Shorter arrays have lower precedence in JSONB, so we must
        -- ensure that they have the same length
        prerelease := to_jsonb(array_fill(NULL::bool, ARRAY[max_prerelease_parts]));

        -- Split prerelease string by `.` and append items to `prerelease` array
        FOREACH prerelease_part IN ARRAY string_to_array(match_result[4], '.')
        LOOP
            -- Parse parts as numbers if they consist of only digits
            IF regexp_like(prerelease_part, '^\d+$') THEN
                -- In JSONB a number has higher precedence than a string
                -- but in semver it is the other way around, so we use true/false
                -- to work around this.
                prerelease := jsonb_set(prerelease, array[i::text], to_jsonb(false));
                prerelease := jsonb_set(prerelease, array[(i + 1)::text], to_jsonb(prerelease_part::numeric));
            ELSE
                prerelease := jsonb_set(prerelease, array[i::text], to_jsonb(true));
                prerelease := jsonb_set(prerelease, array[(i + 1)::text], to_jsonb(prerelease_part));
            END IF;

            i := i + 2;
            EXIT WHEN i > max_prerelease_parts;
        END LOOP;
    END IF;

    RETURN json_build_array(
        match_result[1]::numeric,
        match_result[2]::numeric,
        match_result[3]::numeric,
        prerelease
    );
END;
$$ LANGUAGE plpgsql IMMUTABLE;