docs: registry

pkg/engine/engine.go

@@ -2,11 +2,17 @@
 // expression.
 package engine
 
-// A Process handles the reduction of a
+// A Process handles the reduction of a single expression.
 type Process[T any] interface {
+	// Get the current state of the process.
+	// Returns an error if the current state cannot be represented.
 	Get() (T, error)
+
+	// Step performs reduction(s) on the representation. If the number of steps
+	// defined is less than zero, it will perform as many reductions as
+	// possible. Returns whether a reduction was performed.
 	Step(int) bool
 }
 
-// An Engine is an object that handles
+// An Engine is an function that generates reduction processes.
 type Engine[T any] = func(T) (Process[T], error)