I posted an incomplete version of this post by mistake. I have deleted the 
incomplete post.

#1867 <https://github.com/leo-editor/leo-editor/issues/1867> suggests 
retaining only the basic features of the rst3 command used in LeoDocs.leo.

*Overview*

This project has been a great success:

- The rst3 command should work exactly as before for those who use only the 
basic features. If not, please report a bug.

- Regenerating all of Leo's web site appears to work.

- The rst3 sources, in leoRst.py, are now straightforward. All evil kwargs 
are gone, the call chains are much simpler, and much other cruft is gone.

- The simplified code in leoRst.py allows a new, simple, general way for 
Leonistas with scripting skills to create bespoke content from existing 
nodes *anywhere *in an outline. I'll discuss this new scheme below.


*Aha: Writers alone are responsible for content*

The supposed limitations of Leo's rst3 command have been the subject of 
discussion for about two decades. For example, there have been many 
requests for "half clones," clones that don't contain their descendants. 
The faux-advanced rst3 features were a feeble attempt at a workaround.

The advanced features are misguided because* writers alone are responsible 
for the content of @rst trees*. rst3 merely supports organizing the content 
with outlines.

Writers are free to use clones within @rst trees if that works. If not, 
writers must create bespoke content, possibly by cutting and pasting text.

This principle cuts the Gordian Knot. But do not despair. I will soon 
implement a sensational new way for Leonistas with scripting skills to 
create bespoke content from existing nodes *anywhere *in an outline. Let me 
explain.

*Custom content filters*

The rst3 command creates *sources* from @rst trees. These sources can be 
written to *intermediate files* or passed to docutils and written to 
so-called *docutils files*.

In the new code, rst.writeNode creates *all *the sources.

writeNode writes headlines (p.h) as follows:

self.result_list.append(self.underline(p.h))

writeNode writes bodies (p.b) this way:

self.result_list.append(p.b)

Just two lines of code do all the work. Well, suppose we allow Leonistas to 
define *headline and body filters*, and use those filters as follows:

self.result_list.append(self.underline(self.filter_h(p)))

and

self.result_list.append(self.filter_b(p))

*@data headline-filter* and *@data body-filter* will define the filters.  The 
*default filters* will return p.h and p.b. 

On startup, rst.reloadSettings will compile the scripts in the two @data 
nodes. If successful, the filter_b and filter_h methods will wrap the 
user-defined filters. reloadSettings will use the default filters if the 
user-defined filters fail to compile.

Given position p, filters have complete access  (via c = p.v.context) to 
the entire outline! Filters can return any string they like, including '' 
or None. 

It gets better. Writers can store their "intentions" anywhere they like, 
including:

- In headlines of certain kinds, including, say, headlines matching regular 
expressions.
- In bodies of certain kinds, including comments, doc parts, or plain text 
matching patterns defined, say, by regular expressions.
- In uA's (p.v.u)
- In caches.

In short, a filter can use p.b, p.h, p.u, or p.gnx for p itself, but the 
filter can use p (and c = p.v.context) to access any ancestor or descendant 
node, or indeed any other node in the outline.  Nothing could be simpler or 
more general. 

Aha! *Icons can (optionally) mark nodes containing uA's*. So writers can, 
if they want, see the nodes that will result in special handling by the 
rst3 command! This Aha clarifies why I won't do #588 
<https://github.com/leo-editor/leo-editor/issues/588>.

*Summary*

The simplified rst3 command will work exactly as before for most Leonistas.

*Aha*: Writers are *solely* responsible for the contents of @rst trees. 
This principle should end decades of discussions.

*Aha*: Content filters will modify how rst3 handles @rst trees in a 
completely general way. Event filters have (using p) full access to the 
entire outline, including all ancestors and descendants of p.

*Aha*: Leonistas can use icons (defined in uA's) to mark the presence of 
any *other* uAs, including uA's that contain the writer's "intentions," 
that is, uA's that control the new filters.

In short, simplifying the rst3 command has created three huge Aha's.

Edward

P. S.* Python's text tools are evolving*

Tools such as sphinx and docutils continue to become more capable. For 
example, sphinx now uses pygments for all syntax coloring. There is no need 
to support SilverCity or provide settings for code blocks.

As a result of these improvements, I am simplifying the @rst trees in 
LeoDocs.leo.

EKR

-- 
You received this message because you are subscribed to the Google Groups 
"leo-editor" group.
To unsubscribe from this group and stop receiving emails from it, send an email 
to [email protected].
To view this discussion on the web visit 
https://groups.google.com/d/msgid/leo-editor/b3fe53ff-5421-4b66-b4c2-1186c8335e4cn%40googlegroups.com.

Reply via email to