Groups | Search | Server Info | Keyboard shortcuts | Login | Register [http] [https] [nntp] [nntps]

Groups > comp.lang.python > #26217 > unrolled thread

simplified Python parsing question

Back to article view | Back to comp.lang.python

Contents

  simplified Python parsing question "Eric S. Johansson" <esj@harvee.org> - 2012-07-29 19:21 -0400
    Re: simplified Python parsing question Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2012-07-30 03:33 +0000
      Re: simplified Python parsing question "Eric S. Johansson" <esj@harvee.org> - 2012-07-30 02:17 -0400

#26217 — simplified Python parsing question

as some folks may remember, I have been working on making Python and its tool 
base more accessible to disabled programmers. I've finally come up with a really 
simple technique which should solve 80% of the problem. What I need to figure 
out is how to find a spot in the code where a symbol exists and potentially, 
it's rough type (class name, instance, etc.). This is really a much bigger 
question that I want to get into right now but I'm looking just to build a demo 
to back up a storyboard plus video.

When you are sitting on or in a name, you look to the left or look to the right 
what would you see that would tell you that you have gone past the end of that 
name. For example

a = b + c

if you are sitting on a, the boundaries are beginning of line and =, if you are 
sitting on b, the boundaries are = and +, if you are sitting on c, the 
boundaries are + and end of line.  a call the region between those boundaries 
the symbol region.

if this example is clear to you, what you suggest for a method of finding a 
whole statement, or a whole symbol region? note, doesn't have to be perfect or 
complete solution, just good enough to let me do a moderately complex demo and 
seek funding accessibility world to build a complete environment.

I appreciate the help because I believe that once this is working, it'll make a 
significant difference in the ability for disabled programmers to write code 
again as well as be able to integrate within existing development team and their 
naming conventions.

Looking forward to responses.

--- eric

first draft write up of technique
https://docs.google.com/document/d/1In11apApKozw_UOPAhVz0ePqns72_6652Dra34xWp4E/edit

[toc] | [next] | [standalone]

#26225

On Sun, 29 Jul 2012 19:21:49 -0400, Eric S. Johansson wrote:

> When you are sitting on or in a name, you look to the left or look to
> the right what would you see that would tell you that you have gone past
> the end of that name. For example

Have you read the docs? It gives full details of the Python syntax.

http://docs.python.org/reference/index.html

For example:

http://docs.python.org/reference/simple_stmts.html#assignment-statements

See also:

http://docs.python.org/library/language.html
http://effbot.org/zone/simple-top-down-parsing.htm
http://nedbatchelder.com/text/python-parsers.html


Here's a Python parser using the pyparsing library. It's a bit old 
(written for Python 2.4) but it shouldn't be hard to update it to new 
syntax:

http://pyparsing.wikispaces.com/file/view/pythonGrammarParser.py



-- 
Steven

[toc] | [prev] | [next] | [standalone]

#26231

On 7/29/2012 11:33 PM, Steven D'Aprano wrote:
> On Sun, 29 Jul 2012 19:21:49 -0400, Eric S. Johansson wrote:
>
>> When you are sitting on or in a name, you look to the left or look to
>> the right what would you see that would tell you that you have gone past
>> the end of that name. For example
> Have you read the docs? It gives full details of the Python syntax.

Yes I have. I was hoping for a different perspective because what I'm trying to 
do is middle out parsing. Top-down when the scanner focus moves from left to 
right and bottom up when the scanner focus moves from right to left.

sounds kind of odd when I describe it that way but both the cursor is on the 
middle of a name string and I need to look to either end of that name string 
before can do a conversion to a symbol string, I have to look at both ends in 
different ways. If you've read the documentation I've provided, would it be a 
better example to use for describing some of the issues. Here's a very rough 
draft of a storyboard

https://docs.google.com/presentation/d/1fuKyo9AE6i9ZdX2lucwK0v_W5Kx9M3Mezavm40wzCo8/edit

the first 13-14 slides are the working content for the storyboard. the rest is 
mostly "memory" of things I was thinking about so if it doesn't make sense or 
seems wrong, don't give me grief. :-)

> Here's a Python parser using the pyparsing library. It's a bit old
> (written for Python 2.4) but it shouldn't be hard to update it to new
> syntax:
>
> http://pyparsing.wikispaces.com/file/view/pythonGrammarParser.py
>

thanks for the reference. I'll take a look at it as well.

[toc] | [prev] | [standalone]

Back to top | Article view | comp.lang.python

csiph-web