Any way to define a function with parameters?

[Jisoo Song]

Let's think of general quadratic function: a*x**2 + b*x + c. Commonly, this function is represented as f(x) = a*x**2 + b*x + c.

However, we can also write it as f(x; a,b,c), which implies that a,b and c can also be replaced by other values.

Does sympy have algorithm for such notation, so that `f(x, evaluate=False)` returns `f(x; a,b,c)`?

[S.Y. Lee]

I don't think that a*x**2 + b*x + c.is actually considered a 'Function', but just as an 'Expression' in sympy.

And literally you can just apply (a*x**2 + b*x + c).subs({a: 1}) to do evaluations with respect to any variables. 

[Jisoo Song]

2020년 3월 28일 토요일 오전 12시 1분 34초 UTC+9, S.Y. Lee 님의 말:

 a*x**2 + b*x + c is clearly not a function, but `f(x)` which returns ` a*x**2 + b*x + c` is, a function.

We can write a code like this:

class f(Function):

    @classmethod

    def eval(cls, x):

        return a*x**2 + b*x + c

What I wanted to do was to generate another function class from f, which will have 1 for `a` so that it can return x**2 + b*x + c when called.

I think this will need some metaclass-related tweaks by now.