Regex in PowerQuery

When dealing with messy data, it's often paramount to do some text transforms to clean it up a little. I end up writing a lot of regex and just having ChatGPT translate it into Power Query steps/functions because manually transforming text is such a pain in Power Query without regex. It's very quick for me to write regex due to how close the final syntax usually is to the text I'm matching.

For context, a simple regex-based prefix matcher like this:

^[A-Z]{3}-\d{4}\s*(?=\D)

Translates into a Power Query function along the lines of:

(text as nullable text) as nullable text =>
let
    t = text,

    Prefix = if t <> null and Text.Length(t) >= 8
        then Text.Start(t, 8)
        else "",

    ValidPrefix =
        Text.Length(Prefix) = 8 and
        Text.Middle(Prefix, 3, 1) = "-" and

        // First 3 uppercase letters
        List.AllTrue(
            List.Transform(
                Text.ToList(Text.Start(Prefix, 3)),
                each Character.ToNumber(_) >= 65 and Character.ToNumber(_) <= 90
            )
        ) and

        // Last 4 digits
        List.AllTrue(
            List.Transform(
                Text.ToList(Text.End(Prefix, 4)),
                each Character.ToNumber(_) >= 48 and Character.ToNumber(_) <= 57
            )
        ),

    AfterPrefix =
        if ValidPrefix
        then Text.Range(t, 8)
        else t,

    TrimmedAfter =
        if ValidPrefix
        then Text.TrimStart(AfterPrefix)
        else t,

    // Lookahead equivalent: next char must be non-digit (or absent)
    NextCharValid =
        Text.Length(AfterPrefix) = 0 or
        not List.Contains({"0".."9"}, Text.Start(TrimmedAfter, 1)),

    Result =
        if ValidPrefix and NextCharValid
        then TrimmedAfter
        else t
in
    Result