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Meta-code confusion
From: |
Doug Lewan |
Subject: |
Meta-code confusion |
Date: |
Fri, 10 Aug 2012 19:12:08 +0000 |
I have development environment that has a handful of files with isomorphic (but
not identical) structures.
I'd like to use the same code to define modes for all of them, but clearly
there are things I don't understand about writing meta-code in emacs lisp.
As a starting point I'm failing with the following:
(defvar *pp-symbol-re* "\\(?:\\s_\\|\\sw\\)")
(defun ppm-define-vars (name abbreviation)
"Build a list of vars for the new mode."
(let* ((start-var-name (format "*pp-%s-start-re*" abbreviation))
(start-var (make-symbol start-var-name))
(start-re (list 'concat (format "^%s\\s-+" name) '*pp-symbol-re*)))
(list (list 'defvar start-var start-re))))
I want all such functions to return a list of definitions of the type of
interest.
This one happens to return a list of one element, [I would like] a variable
definition.
It certainly looks like it's returning the right kind of thing:
(car (ppm-define-vars "douglas" "dug"))
=> (defvar *pp-dug-start-re* (concat "^douglas\\s-+" *pp-symbol-re*))
And (eval) looks like it does the right thing:
(eval (car (ppm-define-vars "douglas" "dug")))
=> *pp-dug-start-re*
(defvar) returns a symbol and (symbolp) confirms that that is a symbol.
However, using *pp-dug-start-re* gets a void-variable error.
On the other hand
(boundp (eval (car (ppm-define-vars "douglas" "dug"))))
=> t
which would seem to be a contradiction.
I'm using
GNU Emacs 24.1.1 (i686-pc-cygwin, GTK+ Version 2.24.10) of 2012-07-17 on fiona
and
GNU Emacs 24.1.1 (powerpc-ibm-aix6.1.0.0, X toolkit, Xaw scroll bars) of
2012-07-25 on devlpar1.
I would gladly pay with a beer¹ to understand this better.
,Douglas
Douglas Lewan
Shubert Ticketing
(201) 489-8600 ext 224
There is no national science just as there is no national multiplication table;
what is national is no longer science. - Anton Checov
_____________
¹ "beer" is a variable, replace it with an appropriate value should beer be
distasteful to you or otherwise inappropriate.
- Meta-code confusion,
Doug Lewan <=