From e159a4defc639640f41efa3879bb9187761237f7 Mon Sep 17 00:00:00 2001
From: Sven Greb <development@svengreb.de>
Date: Mon, 23 Nov 2020 15:50:12 +0100
Subject: [PATCH] Spell incantation options "mixin"

To allow to compose, manipulate and read spell incantation options afte
the initial creation, two new types will be added for the spell
packages [1]:

- <I> `spell.Options` - A `interface` type as a generic representation
  for `spell.Incantation` options.
- <I> `spell.Mixin` - A `interface` type that allows to compose
  functions that process `spell.Options` of `spell.Incantation`s.
  - `Apply(Options) (Options, error)` - applies generic `spell.Options`
    to `spell.Incantation` options.

[1]: https://pkg.go.dev/github.com/svengreb/wand/pkg/spell

GH-25
---
 pkg/spell/mixin.go | 13 +++++++++++++
 pkg/spell/spell.go |  2 +-
 2 files changed, 14 insertions(+), 1 deletion(-)
 create mode 100644 pkg/spell/mixin.go

diff --git a/pkg/spell/mixin.go b/pkg/spell/mixin.go
new file mode 100644
index 0000000..981f35f
--- /dev/null
+++ b/pkg/spell/mixin.go
@@ -0,0 +1,13 @@
+// Copyright (c) 2019-present Sven Greb <development@svengreb.de>
+// This source code is licensed under the MIT license found in the LICENSE file.
+
+package spell
+
+// Options is a generic representation for spell incantation options.
+type Options interface{}
+
+// Mixin allows to compose functions that process Options of spell incantations.
+type Mixin interface {
+	// Apply applies generic Options to spell incantation options.
+	Apply(Options) (Options, error)
+}
diff --git a/pkg/spell/spell.go b/pkg/spell/spell.go
index a53fbbb..40b449b 100644
--- a/pkg/spell/spell.go
+++ b/pkg/spell/spell.go
@@ -30,7 +30,7 @@ type Incantation interface {
 	// Kind returns the Kind of a spell.
 	Kind() Kind
 
-	// Options return the options of a spell.
+	// Options returns the options of a spell.
 	Options() interface{}
 }