feat: new engine format

internal/registry/engine.go

@@ -7,7 +7,7 @@ import (
 )
 
 type Engine interface {
-	Load() Process
+	Load(Repr) (Process, error)
 	Name() string
 	InType() string
 }
@@ -22,8 +22,18 @@ func (e convertedEngine[T]) InType() string { return e.inType }
 
 func (e convertedEngine[T]) Name() string { return e.name }
 
-func (e convertedEngine[T]) Load() Process {
-	return convertedProcess[T]{e.engine.Load(), e.inType}
+func (e convertedEngine[T]) Load(r Repr) (Process, error) {
+	t, ok := r.Data().(T)
+	if !ok {
+		return nil, fmt.Errorf("'ncorrent format '%s' for engine '%s'", r.ID(), e.inType)
+	}
+
+	process, err := e.engine(t)
+	if err != nil {
+		return nil, err
+	}
+
+	return convertedProcess[T]{process, e.inType}, nil
 }
 
 func RegisterEngine[T any](registry *Registry, e engine.Engine[T], name, inType string) error {

internal/registry/process.go

@@ -1,8 +1,6 @@
 package registry
 
 import (
-	"fmt"
-
 	"git.maximhutz.com/max/lambda/pkg/engine"
 )
 
@@ -28,14 +26,6 @@ func (b convertedProcess[T]) Get() (Repr, error) {
 	return NewRepr(b.inType, s), nil
 }
 
-func (b convertedProcess[T]) Set(r Repr) error {
-	if t, ok := r.Data().(T); ok {
-		return b.process.Set(t)
-	}
-
-	return fmt.Errorf("Incorrent format '%s' for engine '%s'.", r.ID(), b.inType)
-}
-
 func (b convertedProcess[T]) Step(i int) bool {
 	return b.process.Step(i)
 }

internal/registry/repr.go

@@ -1,11 +1,14 @@
 package registry
 
+// A Repr is a lambda calculus expression. It can have any type of
+// representation, so long as that class is known to the registry it is handled
+// by.
 type Repr interface {
-	// Id returns to name of the objects underlying representation. If is
-	// assumed that if two Repr objects have the same Id(), they share the same
-	// representation.
+	// ID returns the name of the underlying representation. It is assumed that
+	// if two expressions have the same Id(), they have the same representation.
 	ID() string
 
+	// The base expression data.
 	Data() any
 }