{"id":176,"date":"2015-09-01T02:47:16","date_gmt":"2015-09-01T02:47:16","guid":{"rendered":"http:\/\/www.voidbred.com\/blog\/?p=176"},"modified":"2015-09-01T02:47:16","modified_gmt":"2015-09-01T02:47:16","slug":"automatic-f-compilation-in-unity","status":"publish","type":"post","link":"http:\/\/www.voidbred.com\/blog\/2015\/09\/automatic-f-compilation-in-unity\/","title":{"rendered":"Automatic F# Compilation in Unity"},"content":{"rendered":"

I was playing around with F# and Unity integration and there are some nice examples out there \u00a0but they all relied on compilation systems outside of Unity, build some .dll in Xamarin then drop it into a Unity project<\/em>. \u00a0Cool, but it’s not usable if we don’t hook into Unity’s build system and get a fresh build every time we edit a .fs file. \u00a0So, I decided to explore doing just that with UnityEditor.AssetPostprocessor. \u00a0When you implement a AssetPostprocessor you get called with a message every time you reimport an Asset. \u00a0This happens when the file gets touched on disk. \u00a0So what we can do with AssetPostprocessor is recompile a .dll full of F# code whenever a dependent F# file is edited.<\/p>\n

Here is example code of that method:<\/p>\n

using System;\r\nusing UnityEditor;\r\nusing UnityEngine;\r\n\r\nnamespace PostProcessor\r\n{\r\n    public class FSCompiler : AssetPostprocessor\r\n    {\r\n        static void OnPostprocessAllAssets(string[] importedAssets,\r\n                                           string[] deletedAssets,\r\n                                           string[] movedAssets,\r\n                                           string[] movedFromAssetPaths) \r\n        {\r\n            foreach (var str in importedAssets)\r\n            {\r\n                Debug.Log(\"Reimported Asset: \" + str);\r\n                if (System.IO.Path.GetExtension(str) == \".fs\") {\r\n                    var cmd = \"\/Library\/Frameworks\/Mono.framework\/Commands\/fsharpc\";\r\n                    var outDir = System.IO.Path.GetDirectoryName(str);\r\n                    var filenameBase = System.IO.Path.GetFileNameWithoutExtension(str);\r\n                    var outPath = System.IO.Path.Combine(outDir, filenameBase + \".dll\");\r\n                    var args = \" --target:library --reference:\/Applications\/Unity\/Unity.app\/Contents\/Frameworks\/Managed\/UnityEngine.dll \" + str + \" --out:\" + outPath;\r\n                    var process = System.Diagnostics.Process.Start(cmd, args);\r\n                    process.WaitForExit();\r\n                    if (process.ExitCode != 0) {\r\n                        throw new ArgumentException(str);\r\n                    }\r\n                    Debug.Log (\"exec:\"+ process.ExitCode + \" \" + cmd + \" \" + args);                \r\n                    AssetDatabase.ImportAsset(outPath);\r\n                }\r\n            }\r\n        }\r\n    }\r\n}<\/pre>\n
In order to actually use this you’ll need to build a target in MonoDevelop for a .dll that will contain this AssetPostprocessor. \u00a0Put that .dll in your project’s Assets. \u00a0You’ll also have to make sure that your Unity project has FSharp.Core.dll as an Asset if you want to use your F# code. \u00a0I had luck using version 2.3.0. \u00a0You can check the version with “monodis –assembly <path to dll>”. \u00a0The build rule will have to be made a bit more robust if you wanted to compile something with a more complex dependency tree of course. \u00a0If you need help making MonoBehaviours in F#,\u00a0this will help.<\/a><\/p>\n
Sorry I didn’t didn’t post this on Github. \u00a0There is a considerable amount of work to make this idea handle most cases. \u00a0It served my purpose as is, maybe I’ll package it up later.<\/p>\n","protected":false},"excerpt":{"rendered":"
I was playing around with F# and Unity integration and there are some nice examples out there \u00a0but they all relied on compilation systems outside of Unity, build some .dll in Xamarin then drop it into a Unity project. \u00a0Cool, but it’s not usable if we don’t hook into Unity’s build system and get a…<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":[],"categories":[1],"tags":[27,11],"_links":{"self":[{"href":"http:\/\/www.voidbred.com\/blog\/wp-json\/wp\/v2\/posts\/176"}],"collection":[{"href":"http:\/\/www.voidbred.com\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/www.voidbred.com\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/www.voidbred.com\/blog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"http:\/\/www.voidbred.com\/blog\/wp-json\/wp\/v2\/comments?post=176"}],"version-history":[{"count":2,"href":"http:\/\/www.voidbred.com\/blog\/wp-json\/wp\/v2\/posts\/176\/revisions"}],"predecessor-version":[{"id":178,"href":"http:\/\/www.voidbred.com\/blog\/wp-json\/wp\/v2\/posts\/176\/revisions\/178"}],"wp:attachment":[{"href":"http:\/\/www.voidbred.com\/blog\/wp-json\/wp\/v2\/media?parent=176"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/www.voidbred.com\/blog\/wp-json\/wp\/v2\/categories?post=176"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/www.voidbred.com\/blog\/wp-json\/wp\/v2\/tags?post=176"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}