From: Tom Lane <tgl@sss.pgh.pa.us>
To: Chapman Flack <chap@anastigmatix.net>
cc: Andy Fan <zhihui.fan1213@gmail.com>,
        Pavel Stehule <pavel.stehule@gmail.com>,
        jian he <jian.universality@gmail.com>,
        pgsql-hackers <pgsql-hackers@postgresql.org>
Subject: Re: Extract numeric filed in JSONB more effectively
In-reply-to: <900892914fdc3f477b101d699efb40e0@anastigmatix.net>
References: <CAKU4AWoqAVya6PBhn+BCbFaBMt3z-2=i5fKO3bW=6HPhbid2Dw@mail.gmail.com> <CACJufxHASOEpngQ8V2tbXgs4VZC3ETrVbS=uk0KC_B_J1j7ejQ@mail.gmail.com> <CAKU4AWrap1zpYqunJwWTN=CdP7E8e0U4mYmwn7hvTW3ERuENVg@mail.gmail.com> <CAFj8pRD-R-GsGCjeYApbhZoiW8TV6zACaYStMBMM0=--+WgN_A@mail.gmail.com> <CAKU4AWpDdFXAD+dMC1HeErXSKBUUBRGWkf=dAcX3wZgBNsWM=g@mail.gmail.com> <CAFj8pRAO3oEiBaJJ9=HZp6CoP2ffbwSgrKkLKjPfYZwx9wOOuQ@mail.gmail.com> <CAKU4AWoCHpKAVuQeOrk44cVPy_dVxn1aHrMUvHy5Ag-daFCSsQ@mail.gmail.com> <CAFj8pRD4cdUmK0RG4oN5B2KRSeDhwfMYaL=XpfEu4iaLeZ_Kow@mail.gmail.com> <CAKU4AWp8ab61e96v57OaB-Gm1bMfBNVLVy+s17U6_Ne3veB84g@mail.gmail.com> <3507485.1691090027@sss.pgh.pa.us> <CAKU4AWp+KLes8g=BWLqZfDmW9+=ZY0UC4G0i3qVcYEviK_dDTA@mail.gmail.com> <900892914fdc3f477b101d699efb40e0@anastigmatix.net>
Comments: In-reply-to Chapman Flack <chap@anastigmatix.net>
	message dated "Mon, 14 Aug 2023 10:04:03 -0400"
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Date: Mon, 14 Aug 2023 10:10:14 -0400
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Chapman Flack <chap@anastigmatix.net> writes:
> Providing a function with return type declared internal but
> with no parameter of that type is not good,

Not so much "not good" as "absolutely, positively WILL NOT HAPPEN".

> because then a
> user could, in principle, call it and obtain a value of
> 'internal' type, and so get around the typing rules that
> prevent calling other internal functions.

Right --- it'd completely break the system's type-safety for
other internal-using functions.

You could argue that we should never have abused "internal"
to this extent in the first place, compared to inventing a
plethora of internal-ish types to correspond to each of the
things "internal" is used for.  But here we are so we'd
better be darn careful with it.

			regards, tom lane