From mboxrd@z Thu Jan  1 00:00:00 1970
From: Nicolas Goaziou <n.goaziou@gmail.com>
Subject: Re: Invalid read syntax (#) in org-element parse tree
Date: Mon, 11 Feb 2013 22:47:49 +0100
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In-Reply-To: <87vc9ybt65.fsf@gmail.com> (Thorsten Jolitz's message of "Mon, 11
	Feb 2013 19:29:38 +0100")
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To: Thorsten Jolitz <tjolitz@gmail.com>
Cc: emacs-orgmode@gnu.org

Hello,

Thorsten Jolitz <tjolitz@gmail.com> writes:

> here is an excerpt of a parse tree produced with
> 'org-element-parse-buffer': 
>
> ,-------------------------------------------------------------
> | (section (:begin 1 :end 624 :contents-begin
> | 1 :contents-end 623 :post-blank 1 :parent #0) (keyword (:key
> | TITLE :value Program "Blues for Icke" :begin 1 :end
> | 39 :post-blank 0 :post-affiliated 1 :parent #1)))
> `-------------------------------------------------------------
>
> When I evaluate a function with this list as data, I get an error:
>
> ,--------------------------------------------------------
> | Debugger entered--Lisp error: (invalid-read-syntax "#")
> |   read(#<buffer *scratch*>)
> |   preceding-sexp()
> |   eval-last-sexp-1(t)
> |   eval-last-sexp(t)
> |   eval-print-last-sexp()
> |   call-interactively(eval-print-last-sexp nil nil)
> `--------------------------------------------------------

[...]

> There are a lot of usages of '#' in Emacs Lisp, but I couldn't figure
> out how (and why) it is used in ':parent #1'. 

See (info "(elisp) Read Syntax for Circular Objects")

> Nic Ferrier wrote an exhaustive library with "routines for working with
> key/value data structures like hash-tables and alists and plists"
> (https://github.com/nicferrier/emacs-kv/blob/master/kv.el), but I cannot
> apply any of the functions due to the read error. Do I really have to
> treat the parse tree as text first and eliminate the '#' before I can
> use it as list in Emacs Lisp, or did I simply manage to get the wrong
> represantation of the parse tree somehow?

I'm not sure about what you want to do with the parse tree. The usual
function to work with it is `org-element-map'. You may want to have
a look at its docstring, as it contains examples.


Regards,

-- 
Nicolas Goaziou