Re: SQL-spec incompatibilities in similar_escape() and related stuff

On 2019-May-23, Tom Lane wrote:

> + <para>
> + Another nonstandard extension is that following the escape character
> + with a letter or digit provides access to the same escape sequences
> + defined for POSIX regular expressions, below (see
> + <xref linkend="posix-character-entry-escapes-table"/>,
> + <xref linkend="posix-class-shorthand-escapes-table"/>, and
> + <xref linkend="posix-constraint-escapes-table"/>).
> </para>

I think the word "same" in this para is more confusing than helpful;
also the tables are an integral part of this rather than just an
illustration, so they should not be in parenthesis but after only a
semicolon or such. So:

> + Another nonstandard extension is that following the escape character
> + with a letter or digit provides access to the escape sequences
> + defined for POSIX regular expressions; see
> + <xref linkend="posix-character-entry-escapes-table"/>,
> + <xref linkend="posix-class-shorthand-escapes-table"/>, and
> + <xref linkend="posix-constraint-escapes-table"/> below.

I think it would be useful to provide a trivial example that illustrates
this in the <para> below; say '\mabc\M' not matching "zabc".

All in all, these are pretty trivial points and I would certainly not be
mad if it's committed without these changes.

Marked ready for committer.

--
Álvaro Herrera https://www.2ndQuadrant.com/
PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services