[Pythonsudoku-devel] Code rewrite

[Xosé A. O. F. <xos...@gm...>]

Hi,

I'll begin to rewrite the code, as I advance you in the "help wanted" message. 
I'm planning to rewrite 2 thinks: the file format and how the sudokus are 
solved.


1. File format:
Currently, the file format that Python Sudoku uses is a plain text file with a 
optional header setting the size of the sudoku and a list of values. 0 in 
that list means that the number is not known.

I have already wrote a new version of the file format, but still not in 
subversion, that uses XML to store the information. In the first version only 
the given numbers and the calculated numbers are set.

I'll try to commit the code to work with this format this night.


2. Solver method:
If you have read the pythonsudoku/sudoku.py code you'd find that the code is 
spaghetti code: the 3/4 methods that Python Sudoku already uses are defined 
inside the Sudoku class with the use of methods inside methods...

I'm planning to change the way that the methods are defined. Create a base 
Method class with a solve() method that tries to calculate new values and a 
Sudoku class with methods to get the positions of a row/column/region, to set 
calculate values and to remove possible values.

class Sudoku:
    row(x, y):
        iterator with the positions of the row
    column(x, y):
        iterator with the positions of the column
    region(x, y):
        iterator with the positions of the region

    value(x, y, value):
        set the value of a position


     remove_candidate(x, y, value):
         remove a value from the candidates
         if there is only one candidate:
             value(x, y, VALUE)


    solve():
        continue = True
        while continue:
            continue = False
            for method in self.methods:
                if method.solve():
                    continue = True

    create():
        brute force as is right now

class Method:
    def solve():

I think this way it will be easier to write new methods. What do you think?


Future improvements:
-Pass to the methods the changes from the last execution of the method so it's 
not needed to try to solve all the sudoku.
-Show/save the method used to calculate a value or remove a candidate value.


3. Rewrite branch:
I'll begin to rewrite the code in the rewrite branch [0].

https://pythonsudoku.svn.sourceforge.net/svnroot/pythonsudoku/pythonsudoku/branches/rewrite


As always, any question/idea will be welcomed.