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From: Eric Abrahamsen <eric@ericabrahamsen.net>
To: help-gnu-emacs@gnu.org
Subject: Re: eieio defclass evaluate :initform value
Date: Wed, 04 Jan 2017 12:45:22 -0800	[thread overview]
Message-ID: <87o9zm7dwd.fsf@ericabrahamsen.net> (raw)
In-Reply-To: 20170104120403.6e7c67e8@gauss

Joe Riel <joer@san.rr.com> writes:

> According to the info page for eieio for Emacs 23, one
> could do
>
> (defclass foo-class
>    ((bar :initform (lambda () my-var)
>          :type string)))
>
> When make-instance was called, the lambda expression
> for :initform would be evaluated and the expression
> assigned to my-var would be used for the slot bar.
>
> The info page for eieio Emacs 24 does not mention this 
> functionality and testing shows it no longer exists.
>
> Is there nice way, in 24, to create a class with an :initform
> that, upon instantiation, evaluates to the value of a variable?

Depending on what exactly you want, you might be able to solve it with
`oset-default', which lives outside the class definition, and can
evaluate variables. See if that does what you want?

Eric




  reply	other threads:[~2017-01-04 20:45 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-01-04 20:04 eieio defclass evaluate :initform value Joe Riel
2017-01-04 20:45 ` Eric Abrahamsen [this message]
2017-01-05 16:06   ` Joe Riel
2017-01-05 18:56     ` Eric Abrahamsen
2017-01-04 22:43 ` Stefan Monnier

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