Add prototype action using exec and curl

* Downloads a fixed version Julia binary using curl
* Adds it to PATH
* Runs `julia --version` to test the installation

lib/file.js

@@ -0,0 +1,3 @@
+"use strict";
+// Apparently this satisfies the typescript compiler
+// https://stackoverflow.com/questions/41211566/tsconfig-json-buildno-inputs-were-found-in-config-file/45790421#45790421

lib/setup-julia.js

@@ -0,0 +1,46 @@
+"use strict";
+var __awaiter = (this && this.__awaiter) || function (thisArg, _arguments, P, generator) {
+    return new (P || (P = Promise))(function (resolve, reject) {
+        function fulfilled(value) { try { step(generator.next(value)); } catch (e) { reject(e); } }
+        function rejected(value) { try { step(generator["throw"](value)); } catch (e) { reject(e); } }
+        function step(result) { result.done ? resolve(result.value) : new P(function (resolve) { resolve(result.value); }).then(fulfilled, rejected); }
+        step((generator = generator.apply(thisArg, _arguments || [])).next());
+    });
+};
+var __importStar = (this && this.__importStar) || function (mod) {
+    if (mod && mod.__esModule) return mod;
+    var result = {};
+    if (mod != null) for (var k in mod) if (Object.hasOwnProperty.call(mod, k)) result[k] = mod[k];
+    result["default"] = mod;
+    return result;
+};
+Object.defineProperty(exports, "__esModule", { value: true });
+const core = __importStar(require("@actions/core"));
+const exec = __importStar(require("@actions/exec"));
+const os = __importStar(require("os"));
+function run() {
+    return __awaiter(this, void 0, void 0, function* () {
+        try {
+            const version = core.getInput("version");
+            core.debug(`selected Julia version: ${version}`);
+            // Store information about the environment
+            const osPlat = os.platform();
+            const osArch = os.arch();
+            // For now, just download Linux x64 binaries
+            yield exec.exec("curl", [
+                "-O",
+                "https://julialang-s3.julialang.org/bin/linux/x64/1.0/julia-1.0.1-linux-x86_64.tar.gz"
+            ]);
+            yield exec.exec("tar xf julia-1.0.1-linux-x86_64.tar.gz");
+            // Add the downloaded binary to path
+            core.addPath("julia-1.0.1/bin");
+            // Test if it worked
+            yield exec.exec("julia", ["--version"]);
+            yield exec.exec("julia", ["-e", "'using InteractiveUtils; versioninfo()'"]);
+        }
+        catch (error) {
+            core.setFailed(error.message);
+        }
+    });
+}
+run();