From a1d845c264ccac828fb3d5c6f3f5b24e8b550d77 Mon Sep 17 00:00:00 2001
From: Nat Quayle Nelson <natquaylenelson@gmail.com>
Date: Sat, 12 Jun 2021 21:52:32 -0600
Subject: [PATCH] [nat] (saveComponent) and (withComponents)

---
 src/nat/Lib.kiss                              | 36 +++++++++++++++++--
 .../{StringComponents.hx => Author.hx}        |  1 -
 src/nat/components/Name.hx                    |  3 ++
 src/test/TestMain.kiss                        |  7 +++-
 4 files changed, 42 insertions(+), 5 deletions(-)
 rename src/nat/components/{StringComponents.hx => Author.hx} (68%)
 create mode 100644 src/nat/components/Name.hx

diff --git a/src/nat/Lib.kiss b/src/nat/Lib.kiss
index ee6cb1a..6bfed81 100644
--- a/src/nat/Lib.kiss
+++ b/src/nat/Lib.kiss
@@ -4,12 +4,42 @@
 (defmacro hasComponent [e componentType]
     `(.exists .components ,e ,(symbolName componentType)))
 
-// TODO add to the documentation a hint that macros should use fully qualified paths so macro caller classes don't need to import everything
+(defmacro _componentPath [archive e componentType]
+    `(haxe.io.Path.join [.archiveDir (the nat.Archive ,archive) "components" (+ (dictGet (the Map<String,String> .components ,e) ,(symbolName componentType)) ".json")]))
+
 (defmacro getComponent [archive e componentType]
+    // TODO add to the documentation a hint that macros should use fully qualified type paths so macro caller classes don't need to import everything
     `(the nat.components ,componentType 
         (tink.Json.parse
-            (sys.io.File.getContent
-                (haxe.io.Path.join [.archiveDir (the nat.Archive ,archive) "components" (+ (dictGet (the Map<String,String> .components ,e) ,(symbolName componentType)) ".json")])))))
+            (sys.io.File.getContent (_componentPath ,archive ,e ,componentType)))))
+
+// Components have to be saved individually after writing because the Entity only knows their ids,
+// not the data they contain. This is more ergonomically done by using (withComponents...)
+(defmacro saveComponent [archive e componentType c]
+    `(sys.io.File.saveContent
+        (_componentPath ,archive ,e ,componentType)
+        (tink.Json.stringify
+            (the nat.components ,componentType ,c))))
+
+// Retrieve multiple components from an Entity with mutable access.
+// All components will be serialized after the block is done.
+(defmacro withComponents [archive e bindings &rest body]
+    (let [bindingPairs
+                (groups (expList bindings) 2 Throw)
+            bindingList
+                []
+            saveList
+                []
+            retValSymbol
+                (symbol)]
+        (doFor [name type] bindingPairs
+            (bindingList.push `&mut ,name)
+            (bindingList.push `(getComponent ,archive ,e ,type))
+            (saveList.push `(saveComponent ,archive ,e ,type ,name)))
+        `(let [,@bindingList
+                ,retValSymbol {,@body}]
+            ,@saveList
+            ,retValSymbol)))
 
 (defun tagList [archive e]
     (let [t
diff --git a/src/nat/components/StringComponents.hx b/src/nat/components/Author.hx
similarity index 68%
rename from src/nat/components/StringComponents.hx
rename to src/nat/components/Author.hx
index 838abe4..cbffd0f 100644
--- a/src/nat/components/StringComponents.hx
+++ b/src/nat/components/Author.hx
@@ -1,4 +1,3 @@
 package nat.components;
 
-typedef Name = String;
 typedef Author = String;
diff --git a/src/nat/components/Name.hx b/src/nat/components/Name.hx
new file mode 100644
index 0000000..6525d08
--- /dev/null
+++ b/src/nat/components/Name.hx
@@ -0,0 +1,3 @@
+package nat.components;
+
+typedef Name = String;
diff --git a/src/test/TestMain.kiss b/src/test/TestMain.kiss
index 93ae866..fa8c0d1 100644
--- a/src/test/TestMain.kiss
+++ b/src/test/TestMain.kiss
@@ -25,4 +25,9 @@
         (assert !(tagsMatch archive song1 "(and song religious)"))
         (assert (tagsMatch archive song2 "(and song religious)"))
         (assert !(tagsMatch archive song2 "(and song western)"))
-        ))
\ No newline at end of file
+
+        (withComponents archive song1
+            [author Author
+                name Name]
+            (assert (= author "Rafael Krux"))
+            (assert (= name "Adventure")))))
\ No newline at end of file