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From: Pavel Stehule <pavel.stehule@gmail.com>
Date: Thu, 7 Aug 2025 16:16:25 +0200
Message-ID: <CAFj8pRDzBnmztqJY9Zf-DKfK5WYwYzs94R83=w3FjqD1MDvLXQ@mail.gmail.com>
Subject: Re: CALL and named parameters
To: "David G. Johnston" <david.g.johnston@gmail.com>
Cc: Dominique Devienne <ddevienne@gmail.com>, 
	"pgsql-general@lists.postgresql.org" <pgsql-general@lists.postgresql.org>
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Hi

=C4=8Dt 7. 8. 2025 v 15:30 odes=C3=ADlatel David G. Johnston <
david.g.johnston@gmail.com> napsal:

> On Thursday, August 7, 2025, Dominique Devienne <ddevienne@gmail.com>
> wrote:
>>
>>
>> What's not nice is in the way it failed IMHO. I guess I persist it's
>> not a user friendly message :)
>
>
> Then write the error message you would have liked to see.
>
>
>>
>> Can you overload a function solely by changing an argument name?
>
>
> No, the signature is only the name and input argument types.
>
>
>> If not, as I suspect, then function lookup doesn't strictly depend on
>> argument names (like in C++).
>> So the function did exist, with the correct "signature" (ignoring
>> argument names).
>> And I was "just" using the wrong arg-name. That tripped me up.
>
>
> How is it =E2=80=9Cjust=E2=80=9D an argument name when you are using name=
d argument syntax?
>
> David J.
>
>
(2025-08-07 15:58:24) postgres=3D# select fx(b=3D>10);
ERROR:  function fx(b =3D> integer) does not exist
LINE 1: select fx(b=3D>10);
               ^
HINT:  No function matches the given name and argument types. You might
need to add explicit type casts.

The error message and hint is simillary unfriendly like for a case with
unnamed parameters. I am afraid that implementing a more friendly error
message can slow down the query execution :-/. Now we raise errors when we
know, so we didn't find a good signature, but we don't know what is wrong,
so it is difficult to raise errors in the sense that the name of the
argument is wrong.

Regards

Pavel

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<div dir=3D"ltr"><div>Hi</div><br><div class=3D"gmail_quote gmail_quote_con=
tainer"><div dir=3D"ltr" class=3D"gmail_attr">=C4=8Dt 7. 8. 2025 v=C2=A015:=
30 odes=C3=ADlatel David G. Johnston &lt;<a href=3D"mailto:david.g.johnston=
@gmail.com">david.g.johnston@gmail.com</a>&gt; napsal:<br></div><blockquote=
 class=3D"gmail_quote" style=3D"margin:0px 0px 0px 0.8ex;border-left:1px so=
lid rgb(204,204,204);padding-left:1ex">On Thursday, August 7, 2025, Dominiq=
ue Devienne &lt;<a href=3D"mailto:ddevienne@gmail.com" target=3D"_blank">dd=
evienne@gmail.com</a>&gt; wrote:<blockquote class=3D"gmail_quote" style=3D"=
margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-lef=
t:1ex">
<br>
What&#39;s not nice is in the way it failed IMHO. I guess I persist it&#39;=
s<br>
not a user friendly message :)</blockquote><div><br></div><div>Then write t=
he error message you would have liked to see.</div><div>=C2=A0</div><blockq=
uote class=3D"gmail_quote" style=3D"margin:0px 0px 0px 0.8ex;border-left:1p=
x solid rgb(204,204,204);padding-left:1ex">
<br>
Can you overload a function solely by changing an argument name?</blockquot=
e><div><br></div><div>No, the signature is only the name and input argument=
 types.</div><div>=C2=A0</div><blockquote class=3D"gmail_quote" style=3D"ma=
rgin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:=
1ex">
If not, as I suspect, then function lookup doesn&#39;t strictly depend on<b=
r>
argument names (like in C++).<br>
So the function did exist, with the correct &quot;signature&quot; (ignoring=
<br>
argument names).<br>
And I was &quot;just&quot; using the wrong arg-name. That tripped me up.</b=
lockquote><div><br></div><div>How is it =E2=80=9Cjust=E2=80=9D an argument =
name when you are using named argument syntax?</div><div><br></div><div>Dav=
id J.</div><div><br></div></blockquote><div><br></div><div>(2025-08-07 15:5=
8:24) postgres=3D# select fx(b=3D&gt;10);<br>ERROR: =C2=A0function fx(b =3D=
&gt; integer) does not exist<br>LINE 1: select fx(b=3D&gt;10);<br>=C2=A0 =
=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0^<br>HINT: =C2=A0No functio=
n matches the given name and argument types. You might need to add explicit=
 type casts.</div><div><br></div><div>The error message and hint is similla=
ry unfriendly like for a case with unnamed parameters. I am afraid that imp=
lementing a more friendly error message can slow down the query execution :=
-/. Now we raise errors when we know, so we didn&#39;t find a good signatur=
e, but we don&#39;t know what is wrong, so it is difficult to raise errors =
in the sense that the name of the argument is wrong.=C2=A0</div><div><br></=
div><div>Regards</div><div><br></div><div>Pavel</div><div><br></div><div><b=
r></div><br><div><br></div></div></div>

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