fix(biquad): merge conflicting biquad modules

src/filters/biquad/mod.rs

@@ -1,4 +1,16 @@
-//! Transposed Direct Form II Biquad implementation - nonlinearities based on https://jatinchowdhury18.medium.com/complex-nonlinearities-episode-5-nonlinear-feedback-filters-115e65fc0402
+//! Transposed Direct Form II Biquad implementation
+//!
+//! Nonlinearities based on <https://jatinchowdhury18.medium.com/complex-nonlinearities-episode-5-nonlinear-feedback-filters-115e65fc0402>
+//!
+//! # Usage
+//!
+//! ```rust
+//! use valib::dsp::DSP;
+//! use valib::filters::biquad::Biquad;
+//! use valib::saturators::Tanh;
+//! let mut lowpass = Biquad::<f32, Tanh>::lowpass(0.25 /* normalized frequency */, 0.707 /* Q */);
+//! let output = lowpass.process([0.0]);
+//! ```
 
 use nalgebra::Complex;
 use numeric_literals::replace_float_literals;
@@ -13,7 +25,7 @@ use crate::{
 #[cfg(never)]
 pub mod design;
 
-/// Biquad struct in Transposed Direct Form II. Optionally, a [`Saturator`](crate::saturators::Saturator) instance can be used
+/// Biquad struct in Transposed Direct Form II. Optionally, a [`Saturator`] instance can be used
 /// to apply waveshaping to the internal states.
 #[derive(Debug, Copy, Clone)]
 pub struct Biquad<T, S> {
@@ -23,6 +35,7 @@ pub struct Biquad<T, S> {
     sats: [S; 2],
 }
 
+// TODO: No need to restrict this on dynamic saturators only
 impl<T> Biquad<T, Dynamic<T>> {
     /// Apply these new saturators to this Biquad instance, returning a new instance of it.
     pub fn with_saturators(mut self, a: Dynamic<T>, b: Dynamic<T>) -> Biquad<T, Dynamic<T>> {
@@ -43,6 +56,7 @@ impl<T: Copy, S> Biquad<T, S> {
     }
 }
 
+// TODO: Make those return linear biquads, where the user can then pass their saturators directly through `with_saturators`
 impl<T: Scalar, S: Default> Biquad<T, S> {
     /// Create a new instance of a Biquad with the provided poles and zeros coefficients.
     pub fn new(b: [T; 3], a: [T; 2]) -> Self {