diff --git a/TODO.md b/TODO.md
index 1d5500c..c58421b 100644
--- a/TODO.md
+++ b/TODO.md
@@ -1,6 +1,7 @@
 
 ## TODO
 
+- [ ] Raw is duplicated between Lib.Syntax and Lib.Compile, but not detected
 - [ ] vscode - run newt when switching editors
 - [ ] case split
   - We could fake this up:
diff --git a/playground/TODO.md b/playground/TODO.md
index 31d61b9..42778a1 100644
--- a/playground/TODO.md
+++ b/playground/TODO.md
@@ -7,6 +7,7 @@
   - workaround is to visit the file first
   - we can put them in the zip file and pull them over the IPC
 - [ ] make phone layout automatic
+- [ ] case split &c
 - [x] move newt to a worker (shim + newt + listener)
 - [x] tabs for source, compiler output
 - [x] Show errors in editor
@@ -19,4 +20,6 @@
 - [x] save to url (copy from idris2-playground)
 - [ ] click on url
 - [ ] settings
+  - compilation is now optional, what else do we need for newt?
+
 
diff --git a/playground/samples/Tour.newt b/playground/samples/Tour.newt
index 53b4317..a1fc632 100644
--- a/playground/samples/Tour.newt
+++ b/playground/samples/Tour.newt
@@ -1,23 +1,15 @@
 
 
 /-
-  Ok, so this is newt, a dependent typed programming language that
-  I am implementing to learn how they work.  It targets javascript
-  and borrows a lot of syntax from Idris and Agda.
+  This is newt, a self-hosted, dependent typed programming language that
+  compiles to javascript and borrows a lot of syntax from Idris and Agda.
 
-  This page is a very simple web playground based on the monaco editor.
-  It runs newt, compiled by Idris2, in a web worker.
+  This page is a very simple web playground based on the codemirror editor.
+  It runs newt in a web worker.
 
   Block comments follow Lean because they're easier to type on a
   US keyboard.
 
-  The output, to the right, is somewhat noisy and obtuse. You'll see
-  INFO and sometimes ERROR messages that show up in the editor view
-  on hover.  I'm emitting INFO for solved metas.
-
-  The Day1.newt and Day2.newt are last year's advent of code, translated
-  from Lean.
-
 -/
 
 -- One-line comments begin with two hyphens
@@ -27,10 +19,11 @@
 module Tour
 
 -- We can import other modules, with a flat namespace and no cycles,
--- diamonds are ok
+-- diamonds are ok, Prelude is not imported by default, only explicitly
+-- imported modules are in scope
 
--- commented out until we preload other files into the worker
--- import Lib
+-- commented out because we redefine parts of Prelude in this file.
+-- import Prelude
 
 -- We're calling the universe U and are doing type in type for now
 
@@ -39,10 +32,14 @@ data Nat : U where
   Z : Nat
   S : Nat -> Nat
 
+-- Nat-shaped data is turned into numbers in codegen.
+
 -- Multiple names are allowed on the left:
 data Bool : U where
   True False : Bool
 
+-- Enum shaped data becomes a bare string (the constructor name) in codegen.
+
 -- function definitions are equations using dependent pattern matching
 plus : Nat -> Nat -> Nat
 plus Z m = m
@@ -58,7 +55,7 @@ plus' = \ n m => case n of
 
 -- We can define operators. Mixfix is supported, but we don't
 -- allow ambiguity (so you can't have both [_] and [_,_]). See
--- the Reasoning.newt sample for a mixfix example.
+-- the Reasoning.newt sample file for a mixfix example.
 infixl 2 _≡_
 
 -- Here is an equality, like Idris, everything goes to the right of the colon
@@ -84,8 +81,6 @@ instance Add Nat where
   Z + m = m
   (S n) + m = S (n + m)
 
--- and it now finds the implicits, you'll see the solutions to the
--- implicits if you hover over the `+`.
 two : Nat
 two = S Z + S Z
 
@@ -96,14 +91,13 @@ foo a b = ?
 
 -- Newt compiles to javascript, there is a tab to the right that shows the
 -- javascript output. There is some erasure, but inlining is not being done
--- yet.  Dead code elimination will be done if there is a `main` function.
--- That is not the case in this file.
+-- yet.
 
 -- We can define native types, if the type is left off, it defaults to U
 
 ptype SomePrimType : U
 
--- The names of these three types are special, primitive numbers, strings,
+-- The types Int, String, Char are special. Primitive numbers, strings,
 -- and characters inhabit them, respectively. We can match on primitives, but
 -- must provide a default case:
 
@@ -208,3 +202,25 @@ prod xs ys = do
   y <- ys
   pure (x, y)
 
+
+data Unit = MkUnit
+
+ptype World
+
+data IORes a = MkIORes a World
+
+IO : U -> U
+IO a = World -> IORes a
+
+instance Monad IO where
+  bind ma mab = \ w => case ma w of
+    MkIORes a w => mab a w
+  pure = MkIORes
+
+pfunc putStrLn uses (MkIORes MkUnit) : String -> IO Unit := `(s) => (w) => {
+  console.log(s)
+  return Prelude_MkIORes(null,Prelude_MkUnit,w)
+}`
+
+main : IO Unit
+main = putStrLn "Hello, World!"
diff --git a/playground/src/global.d.ts b/playground/src/global.d.ts
index 415c564..dd3170a 100644
--- a/playground/src/global.d.ts
+++ b/playground/src/global.d.ts
@@ -1,3 +1,4 @@
+/// <reference types="vite/client" />
 declare module "*.css";
 export {};
 declare global {
diff --git a/playground/src/help.md b/playground/src/help.md
new file mode 100644
index 0000000..96018a0
--- /dev/null
+++ b/playground/src/help.md
@@ -0,0 +1,29 @@
+# Newt Playground
+
+Newt is a dependent typed programming language that compiles to javascript. This playground embeds the newt compiler and a codemirror based editor.
+
+The editor will typecheck the file with newt and render errors as the file is changed. The current file is saved to localStorage and will be restored if there is no data in the URL. Cmd-s or Ctrl-s will create a url embedding the file contents. There is a layout toggle for phone use.
+
+## Tabs
+
+**Output** - Displays the compiler output, which is also used to render errors and info annotations in the editor.
+
+**JS** - Displays the javascript translation of the file
+
+**Console** - Displays the console output from running the javascript
+
+**Help** - Displays this help file
+
+## Buttons
+
+▶ Compile and run the current file in an iframe, console output is collected to the console tab.
+
+📋 Embed the current file in the URL and copy to clipboard
+
+↕ or ↔ Toggle vertical or horziontal layout (for mobile)
+
+## Keyboard
+
+*C-s or M-s* - Embed the current file in the URL and copy to clipboard
+
+
diff --git a/playground/src/main.ts b/playground/src/main.ts
index 3ba9850..02d1fdc 100644
--- a/playground/src/main.ts
+++ b/playground/src/main.ts
@@ -1,4 +1,4 @@
-import { effect, signal } from "@preact/signals";
+import { signal } from "@preact/signals";
 import { Diagnostic } from "@codemirror/lint";
 import { useEffect, useRef, useState } from "preact/hooks";
 import { h, render, VNode } from "preact";
@@ -15,6 +15,7 @@ import { CMEditor } from "./cmeditor.ts";
 import { deflate } from "./deflate.ts";
 import { inflate } from "./inflate.ts";
 import { IPC } from "./ipc.ts";
+import helpText from "./help.md?raw";
 
 let topData: undefined | TopData;
 
@@ -37,14 +38,14 @@ function md2nodes(md: string)  {
   let list: VNode[] | undefined
   for (let line of md.split("\n")) {
     if (line.startsWith('- ')) {
-      list = list ?? []
+      if (!list) {
+        list = []
+        rval.push(h('ul', {}, list))
+      }
       list.push(h('li', {}, mdline2nodes(line.slice(2))))
       continue
     }
-    if (list) {
-      rval.push(h('ul', {}, list))
-      list = undefined
-    }
+    list = undefined
     if (line.startsWith('# ')) {
       rval.push(h('h2', {}, mdline2nodes(line.slice(2))))
     } else if (line.startsWith('## ')) {
@@ -277,35 +278,7 @@ function Result() {
 }
 
 function Help() {
-  return h("div", { id: "help" },
-    md2nodes(`
-# Newt Playground
-
-The editor will typecheck the file with newt and render errors as the file is changed. The current file is saved to localStorage and will be restored if there is no data in the URL. Cmd-s / Ctrl-s will create a url embedding the file contents. There is a layout toggle for phone use.
-
-## Tabs
-
-**Output** - Displays the compiler output, which is also used to render errors and info annotations in the editor.
-
-**JS** - Displays the javascript translation of the file
-
-**Console** - Displays the console output from running the javascript
-
-**Help** - Displays this help file
-
-## Buttons
-
-▶ Compile and run the current file in an iframe, console output is collected to the console tab.
-
-📋 Embed the current file in the URL and copy to clipboard
-
-↕ or ↔ Toggle vertical or horziontal layout (for mobile)
-
-## Keyboard
-
-*C-s or M-s* - Embed the current file in the URL and copy to clipboard
-`)
-  )
+  return h("div", { id: "help" }, md2nodes(helpText))
 }
 
 function Console() {
diff --git a/src/Lib/Common.newt b/src/Lib/Common.newt
index 6986d98..c5baebe 100644
--- a/src/Lib/Common.newt
+++ b/src/Lib/Common.newt
@@ -92,8 +92,8 @@ fcCol (MkFC file (l, c)) = c
 class HasFC a where
   getFC : a -> FC
 
-
-
+primNS : List String
+primNS = ("Prim" :: Nil)
 
 emptyFC : FC
 emptyFC = MkFC "" (0,0)
diff --git a/src/Lib/Elab.newt b/src/Lib/Elab.newt
index e7d47d7..bf2d031 100644
--- a/src/Lib/Elab.newt
+++ b/src/Lib/Elab.newt
@@ -1162,9 +1162,9 @@ buildLitCases ctx prob fc scnm scty = do
 -- If we lookupRaw "String", we could get different answers in different contexts.
 -- maybe Hardwire this one
 stringType intType charType : QName
-stringType = QN ("Prim" :: Nil) "String"
-intType = QN ("Prim" :: Nil) "Int"
-charType = QN ("Prim" :: Nil) "Char"
+stringType = QN primNS "String"
+intType = QN primNS "Int"
+charType = QN primNS "Char"
 
 litTyName : Literal -> QName
 litTyName (LString str) = stringType
@@ -1213,6 +1213,8 @@ buildTree ctx prob@(MkProb ((MkClause fc constraints Nil expr) :: cs) ty) = do
   -- If we try on creation, we're looping at the moment, because of the possibility
   -- of Ord a -> Ord b -> Ord (a \x b). Need to cut earlier when solving or switch to
   -- Idris method...
+  -- This is necessary for tests/InferenceIssue.newt
+  -- solveAutos below is the important part
   scty' <- case scty' of
     (VMeta fc1 ix sp) => do
       meta <- lookupMeta ix
diff --git a/src/Main.newt b/src/Main.newt
index 6e5e348..645a3ba 100644
--- a/src/Main.newt
+++ b/src/Main.newt
@@ -21,9 +21,6 @@ import Lib.Syntax
 import Node
 import Serialize
 
-primNS : List String
-primNS = ("Prim" :: Nil)
-
 jsonTopContext : M Json
 jsonTopContext = do
   top <- getTop