Re: [Texmacs-dev] Environment at a tree

[Joris van der Hoeven]

On Mon, Nov 20, 2006 at 03:49:08PM +0100, Lionel Elie Mamane wrote:
> Given t a value of type tree in TeXmacs's scheme environment, is there
> an easy way to find the value what a certain TeXmacs variable has at
> that point in the document? Roughly, what the tree (value "foo") would
> be if placed at the place of t. I mean, suppose that the tree-type
> value points at the tree (here) in the following document:
> 
>  (with "foo" "bar"
>    (document
>      "blah"
>      (with "foo" "baz"
>         (session
>           (document
>             (input "$" "Go! Go!")
>           (input (concat "$" (here) "%") "Back! Back!")
>           (output "No luck here."))))))
> 
> I would get "baz". An "easy" way means short of doing tree-up until
> one encounters a (with "foo" . .) or (with . . "foo" . .) or
> (with . . . . "foo" . .) where "." stands for any tree.
> An easy way includes a library routine that would do just that.

This is easy to program as long as you want to retrieve changes
made using 'with'. However, this mechanism is not safe for more
intricated changes in the environment (a macro which modifies
an environment variable, for example). At the moment, you can only
get the correct value of the environement variable for editable
documents in this case (get-env-tree-at). If you want to apply this
for a scheme document, you would first have to open a new buffer
with this scheme document as its contents. But maybe this is overkill
for what you want.