@hackage / linear-grammar

This library provides some simple tools for building abstract syntax trees, representing linear equations and (inclusive) inequalities. As an example:

12x + 3y - 4z + 12 <= 43x - 7b + 8q

Would look like...

f = (12 :: Rational) .*. EVar "x" .+.
    (3 :: Rational) .*. EVar "y" .+.
    (-4 :: Rational) .*. EVar "z" .+.
    ELit 12
    .<=.
    (43 :: Rational) .*. EVar "x" .+.
    (-7 :: Rational) .*. EVar "b" .+.
    (8 :: Rational) .*. EVar "q"

I've added some overloading functionality, to help ease the verbosity of the above statements - an IsString instance, and some other utilities. To pack the equation into standard form, use the sandardForm function:

stdF = standardForm f