# $Id: edit-bindings.org,v 1.2 2018/05/14 05:23:48 g Exp $
#+title: :edit-bindings and #+ATTR_EDIT test file
#+author: Göktuğ Kayaalp

We use the variables ~lexical-binding~, ~truncate-lines~ and
~word-wrap~ for this test/demo.  We assume the first is ~nil~, the
second is set from a file local variable, and for the third we have no
assumptions.

#+BEGIN_SRC elisp :results verbatim
(list lexical-binding truncate-lines word-wrap)
#+END_SRC

#+RESULTS:
: (nil 62 t)

Now we set up the default ~:edit-bindings~ property.

#+PROPERTY: header-args :edit-bindings '((lexical-binding t))

>From now on, we'll do our observations evaluating the forms in source
code blocks via =C-c ' C-M-x=, and evaluating variables via =M-:= in
the edit special buffer.

In edit-special buffer, when editing, we observe that
~lexical-binding~ is set to ~t~:

#+BEGIN_SRC elisp
(eq lexical-binding t)
#+END_SRC

But ~truncate-lines~ is not set:

#+BEGIN_SRC elisp
(eq truncate-lines 62)
#+END_SRC

Copy ~truncate-lines~ over from this file's buffer local variables:

#+BEGIN_SRC elisp :edit-bindings '(truncate-lines)
(list lexical-binding truncate-lines)
#+END_SRC

We observe that now the buffer-wide value is shadoved, and while
truncate lines is passed through, ~lexical-binding~ is not, it's nil.

So we pass both through:

#+BEGIN_SRC elisp :edit-bindings '((lexical-binding t) truncate-lines)
(list (eq truncate-lines 62)
      (eq lexical-binding t))
#+END_SRC

Export blocks can not use header arguments.  Thus we use an element
property called ~ATTR_EDIT~:

#+ATTR_EDIT: ((fill-column 30) truncate-lines)
#+BEGIN_EXPORT latex
Nullam eu ante vel est
convallis dignissim.  Fusce
suscipit, wisi nec facilisis
facilisis, est dui fermentum
leo, quis tempor ligula erat
quis odio.  Nunc porta
vulputate tellus.  Nunc rutrum
turpis sed pede.  Sed
bibendum.
#+END_EXPORT

When we observe the value of ~truncate-lines~, we see that it is 62,
and when we use ~fill-paragraph~, that it wraps according to the new
value of ~fill-column~.

We get an error if we supply a bad varlist, but editing continues
anyways:

#+BEGIN_SRC python :edit-bindings '(("monty" "python"))
print(None)
#+END_SRC

#+ATTR_EDIT: Tea?
#+BEGIN_EXPORT latex
\textit{nope}
#+END_EXPORT

# Local Variables:
# truncate-lines: 62
# End: