October commit

- custom parser support and infra
- type-tagging and traits (untested)
- match expressions

.vscode/launch.json

@@ -0,0 +1,16 @@
+{
+  // Use IntelliSense to learn about possible attributes.
+  // Hover to view descriptions of existing attributes.
+  // For more information, visit: https://go.microsoft.com/fwlink/?linkid=830387
+  "version": "0.2.0",
+  "configurations": [
+    {
+      "type": "lldb",
+      "request": "launch",
+      "name": "Debug",
+      "program": "${workspaceFolder}/<executable file>",
+      "args": [],
+      "cwd": "${workspaceFolder}"
+    }
+  ]
+}