Re: Q: Is there a way to tell why DEBUG trap was triggered?

[Chet Ramey]

On 3/15/20 7:41 AM, Šimon Let wrote:
> Hi All,
> 
> I'm using PROMPT_COMMAND and DEBUG trap to emulate "PRE" and "POST" hooks
> in bash. I have run into the issue where the DEBUG trap gets triggered when
> any custom readline widget/function is executed. I would like to
> programmatically determine if the DEBUG trap was triggered for a "real"
> interactive command or if it was triggered for a custom readline widget.
Since the DEBUG trap happens before the command executes, it's not a real
`post-command' hook.

> I tried to use READLINE_LINE and READLINE_POINT variables but these are not
> set during the DEBUG trap.

They're not set when the the DEBUG trap runs before, say, a shell
function you've bound to a key sequence using `bind -x' is executed, but
they're available to commands called from within that shell function.

> Is there another way that can be used to determine why the DEBUG trap was
> triggered?

No.

> PS: I'm wondering what is your opinion on providing PRE and POST functions
> natively in bash?

I'd have to see a compelling reason to implement them.

Chet
-- 
``The lyf so short, the craft so long to lerne.'' - Chaucer
                 ``Ars longa, vita brevis'' - Hippocrates
Chet Ramey, UTech, CWRU    chet@case.edu    http://tiswww.cwru.edu/~chet/