Elisp newbie: Getting the value from a variable

Elisp newbie: Getting the value from a variable

[Fredrik Oberg]

In my .emacs I assign a variable a value which should be the height of
the default frame:

(setq my-frame-height 70)

Then I can view it's value by doing

(message "Size %d" my-frame-height) 

But when trying to use it fails. I have the following in my .emacs:

(setq default-frame-alist 
      '((menu-bar-lines . 1)
	(top . 5) 
	(left . 100)
	(width . 100) 
	(height . my-frame-height)
	(cursor-color . "white")
	(cursor-type . box)
	(foreground-color . "black")
	(background-color . "white")
	(font . "-*-Courier New-normal-r-*-*-11-82-96-96-c-*-iso8859-1")
	)
)

When starting emacs, the height is ignored. When I check out the
variable default-frame-alist it has the following value:

((tool-bar-lines . 0)
 (menu-bar-lines . 1)
 (top . 5)
 (left . 100)
 (width . 100)
 (height . my-frame-height)
 (cursor-color . "white")
 (cursor-type . box)
 (foreground-color . "black")
 (background-color . "white")
 (font . "-*-Courier New-normal-r-*-*-11-82-96-96-c-*-iso8859-1"))

my-frame-height is underlined and when I click it, its value (70) is
shown. To me it looks like I must "derefer" the variable in some way.
Is this correct? As a newbie on elisp I have no clue on how to do
that. Can somebody help me find out how to solve this?

Many thanks in advance
/Fredrik

Re: Elisp newbie: Getting the value from a variable

[Thomas Link]

> (setq default-frame-alist 
>       '((menu-bar-lines . 1)
> 	(top . 5) 
> 	(left . 100)
> 	(width . 100) 
> 	(height . my-frame-height)
> 	(cursor-color . "white")
> 	(cursor-type . box)
> 	(foreground-color . "black")
> 	(background-color . "white")
> 	(font . "-*-Courier New-normal-r-*-*-11-82-96-96-c-*-iso8859-1")
> 	)
> )


You have to use a backquote (see C-h C-f backquote):

(setq default-frame-alist `(... (height . ,my-frame-height) ...)

Ciao,
Thomas.