Re: JSON doc example (matchiness)

Erik Rijkers <er@xs4all.nl>

From: Erik Rijkers <er@xs4all.nl>
To: Michael Paquier <michael@paquier.xyz>
Cc: pgsql-hackers@lists.postgresql.org
Date: 2021-05-08T16:08:51Z
Lists: pgsql-hackers
On 5/8/21 3:48 AM, Michael Paquier wrote:
> On Fri, May 07, 2021 at 10:18:44PM +0200, Erik Rijkers wrote:
>> The JSON doc has this example (to show the need for double backslash):
>>
>> $ ? (@ like_regex "^\\d+$")
>>
>>
>> The example is not wrong exactly, and can be cast to jsonpath, but as-is can
>> never match anything.
>>
>> I think it'd be helpful to provide that example so that it more probably
>> matches when the user does a quick trial.
>>
>> Llet's change it to something like:
>>
>> $.* ? (@ like_regex "^\\d+$")
> Ah, I see.  What you are telling here is that we match the regex on
> the full JSON string, which is pretty useless, and you are suggesting
> to change things so as we'd match with the key names at the first
> level.  Makes sense.
>
> This paragraph of the docs say:
> "For example, to match strings that contain only digits"
> Could we be more precise here?  "strings" looks to much generic to
> me in this context when actually referring to a set of path of keys in
> a JSON blob.

Yes, "string values"  is probably another small improvement.


> --
> Michael



Commits

  1. Improve documentation example for jsonpath like_regex operator