Re: CSV reader: is it possible to disable trim?

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OK, you convinced me the current implementation is incorrect.   I'll
disable it or make it customizable, after pondering the compatibility
implications.



On Sat, May 16, 2026 at 11:11=E2=80=AFAM Jens Thiele <[email protected]> wrote=
:

> Hi,
>
> by default the CSV reader in text.csv trims whitespace. Is it possible
> to disable this? (yes, CSV is a mess).
>
> I didn't know there is a RFC for it. Reading:
> https://www.rfc-editor.org/rfc/rfc4180
> "
> Within the header and each record, there may be one or more
> fields, separated by commas.  Each line should contain the same
> number of fields throughout the file.  Spaces are considered part
> of a field and should not be ignored.
> "
>
> which "conflicts" with text.csv:
> "Usually, the whitespaces around the field are ignored."
>
> PS: regarding the CSV mess - quoting the COPY man page from PostgreSQL:
> "
> Note
>
> Many programs produce strange and occasionally perverse CSV files,
> so the file format is more a convention than a standard. Thus you
> might encounter some files that cannot be imported using this
> mechanism, and COPY might produce files that other programs cannot
> process.
> "
>
> $ psql
> karme=3D> select * from csvtest;
>  id |              name               | dummy
> ----+---------------------------------+-------
>   1 |  text surrounded by whitespace  |    42
>   2 |  whitespace in front            |    42
>   3 | whitespace afterwards           |    42
>
> karme=3D> copy csvtest to stdout with csv;
> 1, text surrounded by whitespace ,42
> 2, whitespace in front,42
> 3,whitespace afterwards ,42
>
> possible workaround:
>
> karme=3D> copy csvtest to stdout with csv force quote name;
> 1," text surrounded by whitespace ",42
> 2," whitespace in front",42
> 3,"whitespace afterwards ",42
>
>
> _______________________________________________
> Gauche-devel mailing list
> [email protected]
> https://lists.sourceforge.net/lists/listinfo/gauche-devel
>

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<div dir=3D"ltr"><div class=3D"gmail_default" style=3D"font-size:large">OK,=
 you convinced me the current implementation=C2=A0is incorrect.=C2=A0 =C2=
=A0I&#39;ll disable=C2=A0it or make it customizable, after pondering the co=
mpatibility implications.</div><div class=3D"gmail_default" style=3D"font-s=
ize:large"><br></div><div class=3D"gmail_default" style=3D"font-size:large"=
><br></div></div><br><div class=3D"gmail_quote gmail_quote_container"><div =
dir=3D"ltr" class=3D"gmail_attr">On Sat, May 16, 2026 at 11:11=E2=80=AFAM J=
ens Thiele &lt;<a href=3D"mailto:[email protected]">[email protected]</a>&gt; wro=
te:<br></div><blockquote class=3D"gmail_quote" style=3D"margin:0px 0px 0px =
0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex">Hi,<br>
<br>
by default the CSV reader in text.csv trims whitespace. Is it possible<br>
to disable this? (yes, CSV is a mess).<br>
<br>
I didn&#39;t know there is a RFC for it. Reading:<br>
<a href=3D"https://www.rfc-editor.org/rfc/rfc4180" rel=3D"noreferrer" targe=
t=3D"_blank">https://www.rfc-editor.org/rfc/rfc4180</a><br>
&quot;<br>
Within the header and each record, there may be one or more<br>
fields, separated by commas.=C2=A0 Each line should contain the same<br>
number of fields throughout the file.=C2=A0 Spaces are considered part<br>
of a field and should not be ignored.<br>
&quot;<br>
<br>
which &quot;conflicts&quot; with text.csv:<br>
&quot;Usually, the whitespaces around the field are ignored.&quot;<br>
<br>
PS: regarding the CSV mess - quoting the COPY man page from PostgreSQL:<br>
&quot;<br>
Note<br>
<br>
Many programs produce strange and occasionally perverse CSV files,<br>
so the file format is more a convention than a standard. Thus you<br>
might encounter some files that cannot be imported using this<br>
mechanism, and COPY might produce files that other programs cannot<br>
process.<br>
&quot;<br>
<br>
$ psql<br>
karme=3D&gt; select * from csvtest;<br>
=C2=A0id |=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 name=C2=A0 =C2=
=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0| dummy <br>
----+---------------------------------+-------<br>
=C2=A0 1 |=C2=A0 text surrounded by whitespace=C2=A0 |=C2=A0 =C2=A0 42<br>
=C2=A0 2 |=C2=A0 whitespace in front=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=
=A0 |=C2=A0 =C2=A0 42<br>
=C2=A0 3 | whitespace afterwards=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0|=
=C2=A0 =C2=A0 42<br>
<br>
karme=3D&gt; copy csvtest to stdout with csv;<br>
1, text surrounded by whitespace ,42<br>
2, whitespace in front,42<br>
3,whitespace afterwards ,42<br>
<br>
possible workaround:<br>
<br>
karme=3D&gt; copy csvtest to stdout with csv force quote name;<br>
1,&quot; text surrounded by whitespace &quot;,42<br>
2,&quot; whitespace in front&quot;,42<br>
3,&quot;whitespace afterwards &quot;,42<br>
<br>
<br>
_______________________________________________<br>
Gauche-devel mailing list<br>
<a href=3D"mailto:[email protected]" target=3D"_blank">Gau=
[email protected]</a><br>
<a href=3D"https://lists.sourceforge.net/lists/listinfo/gauche-devel" rel=
=3D"noreferrer" target=3D"_blank">https://lists.sourceforge.net/lists/listi=
nfo/gauche-devel</a><br>
</blockquote></div>

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