prowocessing: add documentation of trait experiment

crates/prowocessing/src/experimental/trait_based/pipeline.rs

@@ -2,21 +2,25 @@ use super::data::io::{Inputs, Outputs};
 use super::element::PipelineElement;
 use super::ops::prelude::*;
 
-// TODO:
-// - Bind additional inputs if instruction has more then one and is passd without any additional
-// - allow binding to pointers to other pipelines?
-// - allow referencing earlier data
+/// Builder for the pipelines that are actually run
+///
+/// TODO:
+/// - Bind additional inputs if instruction has more then one and is passd without any additional
+/// - allow binding to pointers to other pipelines?
+/// - allow referencing earlier data
 pub struct PipelineBuilder {
     elements: Vec<Box<dyn PipelineElement>>,
 }
 
 impl PipelineBuilder {
+    /// Create new, empty builder
     pub fn new() -> Self {
         Self {
             elements: Vec::new(),
         }
     }
 
+    /// Insert element into pipeline
     fn insert<T: PipelineElement + 'static>(mut self, el: T) -> Self {
         if let Some(previous_item) = self.elements.last() {
             assert_eq!(
@@ -28,21 +32,25 @@ impl PipelineBuilder {
         self
     }
 
+    /// insert string concatenattion element
     #[must_use]
     pub fn concatenate(self, sec: String) -> Self {
         self.insert(Concatenate(sec))
     }
 
+    /// insert string uppercase element
     #[must_use]
     pub fn upper(self) -> Self {
         self.insert(Upper)
     }
 
+    /// insert string lowercase element
     #[must_use]
     pub fn lower(self) -> Self {
         self.insert(Lower)
     }
 
+    /// insert numeric addition element
     #[must_use]
     #[allow(
         clippy::should_implement_trait,
@@ -52,16 +60,19 @@ impl PipelineBuilder {
         self.insert(Add(sec))
     }
 
+    /// insert numeric subtraction element
     #[must_use]
     pub fn subtract(self, sec: i32) -> Self {
         self.insert(Subtract(sec))
     }
 
+    /// insert stringify element
     #[must_use]
     pub fn stringify(self) -> Self {
         self.insert(Stringify)
     }
 
+    /// Build the pipeline. Doesn't check again - `insert` should verify correctness.
     pub fn build(&self) -> Pipeline {
         let mut r = Vec::new();
 
@@ -77,11 +88,13 @@ impl Default for PipelineBuilder {
     }
 }
 
+/// Runnable pipeline - at the core of this library
 pub struct Pipeline {
     runners: Vec<fn(&Inputs) -> Outputs>,
 }
 
 impl Pipeline {
+    /// run the pipeline
     pub fn run(&self, inputs: Inputs) -> Outputs {
         let mut out: Outputs = inputs.into();