Re: How to test if symbol from string exists?

[Philip Kaludercic]

Jean Louis <bugs@gnu.support> writes:

> I would like to test if symbol exists and is true.
>
> First I have string, like "people", then I can do this:
>
> (symbol-value (intern "rcd-db-people-mode-map")) and it gives me
> result.

I think you want to use intern-soft, to return a symbol if it exists,
and nil if it doesn't. If you want to check if it is "used", boundp
should suffice, regardless of whether you use intern or intern-soft.

> But before asking for the value, I would like to test if symbol
> exists. So I am trying this:
>
> (bound-and-true-p (intern "rcd-db-people-mode-map"))

That is because bound-and-true-p is a macro.

> and I get error:
>
> Wrong type argument: symbolp, (intern "rcd-db-people-mode-map")
>
> as what I am trying to accomplish is to stop updating this function
> with the one below that still does not work:
>
> (defun rcd-db-table-mode-map (table)
>   (cond ((string= "accounts" table) rcd-db-accounts-mode-map)
>       ((string= "acks" table) rcd-db-acks-mode-map)
>       ((string= "addressbookentries" table) 
> rcd-db-addressbookentries-mode-map)
>       ((string= "areas" table) rcd-db-areas-mode-map)
>       ((string= "categories" table) rcd-db-categories-mode-map)
>       ((string= "countries" table) rcd-db-countries-mode-map)
>       ((string= "devt" table) rcd-db-devt-mode-map)
>       ((string= "edit" table) rcd-db-edit-mode-map)
>       ((string= "emails" table) rcd-db-emails-mode-map)
>       ((string= "groups" table) rcd-db-groups-mode-map)
>       ((string= "locationsets" table) rcd-db-locationsets-mode-map)
>       ((string= "mailinglistoptions" table) 
> rcd-db-mailinglistoptions-mode-map)
>       ((string= "notes" table) rcd-db-notes-mode-map)
>       ((string= "pages" table) rcd-db-pages-mode-map)
>       ((string= "people" table) rcd-db-people-mode-map)
>       ((string= "skills" table) rcd-db-skills-mode-map)
>       ((string= "sms" table) rcd-db-sms-mode-map)
>       ((string= "statsdefinitions" table) rcd-db-statsdefinitions-mode-map)
>       (t rcd-db-mode-map)))
>
> so I would like replacing above function with the one here below,
> which is now not working until I solve the problem how to verify for
> the symbol existence, which symbol name I get from string.
>
> (defun rcd-db-table-mode-map (table)
>   (let ((symbol (intern (format "rcd-db-%s-mode-map" table))))
>   (if (bound-and-true-p symbol)
>       (symbol-value symbol)
>     rcd-db-mode-map)))
>
>
> Thank you,
> Jean
>
>

-- 
        Philip K.