Re: how to parse linear equations

[Philip Herron]

On 16/01/2010 15:02, Hans Aberg wrote:
> On 16 Jan 2010, at 15:52, Michael Chen wrote:
>
> > Exactly, I would like to first process the linear expression, which
> > are coefficients and a constant; how can I do it over my ast tree
> > recursively?
> >
> >          +
> >    *               *
> > 2    +          3      -
> >    x   y             z     x
>
> Just make a data structure that can hold a polynomial - linear in your 
> case, with operators + - *. Then just build it as in the calculator 
> case, only that it operates on this polynomial data.
>
>   Hans
>
>
>
>
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Hey,

Ah nice way of doing this would be use the normal calculator example:

expression: expression '+' expression
                  | expression '-' expression
                   ....

But you can use Gaussian Elimination for a set of linear equations to do 
the hard work (to simplify or even solve) for you by creating a matrix, 
although you want to of course be able to handle single linear equations 
it might give you some ideas in how to structure and process the expression.

--Phil