cablehead · cablehead · Feb 26, 2026 · Feb 26, 2026 · Feb 26, 2026 · Feb 26, 2026
diff --git a/README.md b/README.md
@@ -133,9 +133,12 @@ Or from a file:
 $ http-nu :3001 ./serve.nu
 ```
 
-Check out the [`examples/basic.nu`](examples/basic.nu) file in the repository
-for a complete example that implements a mini web server with multiple routes,
-form handling, and streaming responses.
+Run all examples under one server with the [examples hub](examples/README.md):
+
+```bash
+$ http-nu --datastar :3001 examples/serve.nu
+$ http-nu --datastar --store ./store :3001 examples/serve.nu  # enables store-dependent examples
+```
 
 ### UNIX domain sockets
 
@@ -793,6 +796,19 @@ Make module paths available with `-I` / `--include-path`:
 $ http-nu -I ./lib -I ./vendor :3001 '{|req| use mymod.nu; ...}'
 ```
 
+### Runtime Constants
+
+The `$HTTP_NU` const is available in all scripts and reflects the CLI options
+the server was started with:
+
+```nushell
+$HTTP_NU
+# => {dev: false, datastar: true, watch: false, store: "./store", topic: null, expose: null, tls: null, services: false}
+
+$HTTP_NU.store != null  # check if store is available
+$HTTP_NU.dev            # true when --dev was passed
+```
+
 ### Embedded Modules
 
 #### Routing
@@ -835,6 +851,28 @@ Routes match in order. First match wins. Closure tests return a record (match,
 context passed to handler) or null (no match). If no routes match, returns
 `501 Not Implemented`.
 
+**Mounting sub-handlers:**
+
+`mount` serves a handler under a path prefix. Requests to `/prefix` redirect to
+`/prefix/`, then the prefix is stripped before dispatching to the handler.
+Sub-handlers see `$req.mount_prefix` for absolute URL reconstruction.
+
+```nushell
+let api = source api/serve.nu
+let docs = source docs/serve.nu
+
+{|req|
+  dispatch $req [
+    (mount "/api" $api)
+    (mount "/docs" $docs)
+    (route true {|req ctx| "Not Found"})
+  ]
+}
+```
+
+Mounts compose -- a mounted handler can mount further sub-handlers, and
+`$req.mount_prefix` accumulates the full prefix chain.
+
 #### HTML DSL
 
 Build HTML with Nushell. Lisp-style nesting with uppercase tags.

diff --git a/examples/README.md b/examples/README.md
@@ -0,0 +1,38 @@
+# Examples
+
+## Running all examples
+
+The examples hub mounts individual examples under one server:
+
+```bash
+http-nu --datastar :3001 examples/serve.nu
+```
+
+With a store (enables quotes):
+
+```bash
+http-nu --datastar --store ./store :3001 examples/serve.nu
+```
+
+Then visit http://localhost:3001.
+
+## Individual examples
+
+Each example can also be run standalone.
+
+| Example | Command | Description |
+|---------|---------|-------------|
+| basic | `http-nu :3001 examples/basic.nu` | Minimal routes, JSON, streaming, POST echo |
+| datastar-counter | `http-nu --datastar :3001 examples/datastar-counter/serve.nu` | Client-side reactive counter |
+| datastar-sdk | `http-nu --datastar :3001 examples/datastar-sdk/serve.nu` | Datastar SDK feature demo |
+| mermaid-editor | `http-nu --datastar :3001 examples/mermaid-editor/serve.nu` | Live Mermaid diagram editor |
+| templates | `http-nu --datastar --store ./store :3001 examples/templates/serve.nu` | `.mj` file, inline, and topic modes |
+| quotes | `http-nu --datastar --store ./store :3001 examples/quotes/serve.nu` | Live quotes board with SSE |
+| tao | `http-nu --datastar --dev -w :3001 examples/tao/serve.nu` | The Tao of Datastar |
+
+## Store-dependent examples
+
+Quotes and the `/topic` route in templates require `--store`. The hub
+detects `$HTTP_NU.store` at runtime and greys out unavailable examples.
+When `--store` is provided, templates automatically seeds its topics on
+startup.
diff --git a/examples/basic.nu b/examples/basic.nu
@@ -9,11 +9,11 @@
       "<html><body>
         <h1>http-nu demo</h1>
         <ul>
-          <li><a href='/hello'>Hello World</a></li>
-          <li><a href='/json'>JSON Example</a></li>
-          <li><a href='/echo'>POST Echo</a></li>
-          <li><a href='/time'>Current Time</a></li>
-          <li><a href='/info'>Request Info</a></li>
+          <li><a href='./hello'>Hello World</a></li>
+          <li><a href='./json'>JSON Example</a></li>
+          <li><a href='./echo'>POST Echo</a></li>
+          <li><a href='./time'>Current Time</a></li>
+          <li><a href='./info'>Request Info</a></li>
         </ul>
       </body></html>"
     }
@@ -52,6 +52,7 @@
 
     # Time stream example
     "/time" => {
+      let _ = $in
       generate {|_|
         sleep 1sec
         {out: $"Current time: (date now | format date '%Y-%m-%d %H:%M:%S')\n" next: true}

diff --git a/examples/datastar-sdk/serve.nu b/examples/datastar-sdk/serve.nu
@@ -24,18 +24,18 @@ use http-nu/html *
                 DIV
                 (H3 "to datastar-patch-signals")
                 (P "Count: " (SPAN {"data-text": "$count"} "0"))
-                (BUTTON {"data-on:click": "@post('/increment')"} "Increment")
+                (BUTTON {"data-on:click": "@post('./increment')"} "Increment")
               )
               (
                 DIV
                 (H3 "to datastar-execute-script")
-                (BUTTON {"data-on:click": "@post('/hello')"} "Say Hello")
+                (BUTTON {"data-on:click": "@post('./hello')"} "Say Hello")
               )
               (
                 DIV
                 (H3 "to datastar-patch-elements")
                 (DIV {id: "time"} "--:--:--.---")
-                (BUTTON {"data-on:click": "@post('/time')"} "Get Time")
+                (BUTTON {"data-on:click": "@post('./time')"} "Get Time")
               )
             )
           )

diff --git a/examples/mermaid-editor/serve.nu b/examples/mermaid-editor/serve.nu
@@ -38,7 +38,7 @@ def mermaid-el []: string -> record {
             (META {name: "viewport" content: "width=device-width, initial-scale=1"})
             (TITLE "dia2")
             (SCRIPT {type: "module" src: $DATASTAR_JS_PATH})
-            (SCRIPT {type: "module" src: "/mermaid-diagram.js"})
+            (SCRIPT {type: "module" src: "./mermaid-diagram.js"})
             (STYLE "
 * { box-sizing: border-box; margin: 0; padding: 0; }
 body { height: 100dvh; display: flex; font-family: system-ui, sans-serif; }
@@ -61,7 +61,7 @@ mermaid-diagram {
             (DIV {class: "pane"}
               (TEXTAREA {
                 "data-bind:source": true
-                "data-on:input__debounce.500ms": "@post('/')"
+                "data-on:input__debounce.500ms": "@post('./')"
               } $default_source)
             )
             (DIV {class: "pane"}

diff --git a/examples/quotes/serve.nu b/examples/quotes/serve.nu
@@ -2,6 +2,21 @@ use http-nu/router *
 use http-nu/datastar *
 use http-nu/html *
 
+# Filter for `.last --follow` / `.cat --follow` streams.
+# Buffers frames until xs.threshold is seen, then emits the last
+# buffered frame (or null if none) followed by all subsequent frames.
+def threshold-gate [] {
+  generate {|frame, state = {}|
+    if $frame.topic == "xs.threshold" {
+      return {out: $state.last?, next: {reached: true}}
+    }
+    if ("reached" in $state) {
+      return {out: $frame, next: $state}
+    }
+    {next: ($state | upsert last $frame)}
+  }
+}
+
 def quote-html []: record -> record {
   let q = $in
   (
@@ -45,7 +60,9 @@ def quote-html []: record -> record {
   dispatch $req [
     (
       route {method: GET path: "/" has-header: {accept: "text/event-stream"}} {|req ctx|
-        .head quotes --follow
+        .last quotes --follow
+        | threshold-gate
+        | default {meta: {quote: "Waiting for quotes..."}}
         | each {|frame|
           $frame.meta | quote-html | to datastar-patch-elements
         }
@@ -72,7 +89,7 @@ def quote-html []: record -> record {
             (SCRIPT {type: "module" src: $DATASTAR_JS_PATH})
           )
           (
-            BODY {data-init: "@get('/')"}
+            BODY {data-init: "@get('./')"}
             ({quote: "Waiting for quotes..."} | quote-html)
           )
         )

diff --git a/examples/serve.nu b/examples/serve.nu
@@ -0,0 +1,69 @@
+# http-nu examples hub
+#
+# Run: http-nu --datastar :3001 examples/serve.nu
+# With store: http-nu --datastar --store ./store :3001 examples/serve.nu
+
+use http-nu/router *
+use http-nu/html *
+
+let basic = source basic.nu
+let counter = source datastar-counter/serve.nu
+let sdk = source datastar-sdk/serve.nu
+let mermaid = source mermaid-editor/serve.nu
+let templates = source templates/serve.nu
+let quotes = source quotes/serve.nu
+
+let has_store = $HTTP_NU.store != null
+
+def example-link [href: string label: string desc: string --disabled] {
+  if $disabled {
+    LI (SPAN {style: {color: "#9ca3af"}} $label) $" --($desc) " (SPAN {style: {color: "#9ca3af" font-size: "0.85em"}} "(requires --store)")
+  } else {
+    LI (A {href: $href} $label) $" --($desc)"
+  }
+}
+
+let routes = [
+  (
+    route {method: GET path: "/"} {|req ctx|
+      HTML (
+        HEAD
+        (META {charset: "UTF-8"})
+        (META {name: "viewport" content: "width=device-width, initial-scale=1"})
+        (TITLE "http-nu examples")
+        (STYLE "
+body { font-family: system-ui, sans-serif; max-width: 600px; margin: 2rem auto; padding: 0 1rem; }
+a { color: #2563eb; }
+li { margin: 0.5rem 0; }
+")
+      ) (
+        BODY
+        (H1 "http-nu examples")
+        (P (A {href: "https://github.com/cablehead/http-nu/tree/main/examples"} "source on GitHub"))
+        (UL
+          (example-link "./basic/" "basic" "minimal routes, JSON, streaming")
+          (example-link "./datastar-counter/" "datastar-counter" "reactive counter")
+          (example-link "./datastar-sdk/" "datastar-sdk" "SDK feature demo")
+          (example-link "./mermaid-editor/" "mermaid-editor" "live diagram editor")
+          (example-link "./templates/" "templates" ".mj template modes")
+          (example-link "./quotes/" "quotes" "live quotes board" --disabled=(not $has_store))
+        )
+      )
+    }
+  )
+
+  (mount "/basic" $basic)
+  (mount "/datastar-counter" $counter)
+  (mount "/datastar-sdk" $sdk)
+  (mount "/mermaid-editor" $mermaid)
+  (mount "/templates" $templates)
+  ...(if $has_store {
+    [(mount "/quotes" $quotes)]
+  } else {
+    []
+  })
+]
+
+{|req|
+  dispatch $req $routes
+}
diff --git a/examples/templates/nav.html b/examples/templates/nav.html
@@ -1 +1 @@
-<nav><a href="/">Home</a> | Page (from disk)</nav>
+<nav><a href="./">Home</a> | Page (from disk)</nav>
diff --git a/examples/templates/serve.nu b/examples/templates/serve.nu
@@ -1,3 +1,10 @@
+# Seed store topics from disk files when --store is enabled
+if $HTTP_NU.store != null {
+  open examples/templates/topics/page.html | .append page.html
+  open examples/templates/topics/base.html | .append base.html
+  open examples/templates/topics/nav.html | .append nav.html
+}
+
 {|req|
   match $req.path {
     "/file" => { {name: "World"} | .mj "examples/templates/page.html" }
@@ -6,8 +13,8 @@
       {} | .mj --inline '<h1>Templates</h1>
 <p>This page is rendered with <code>.mj --inline</code>.</p>
 <ul>
-  <li><a href="/file">File mode</a> - extends and include from disk</li>
-  <li><a href="/topic">Topic mode</a> - extends and include from store</li>
+  <li><a href="./file">File mode</a> - extends and include from disk</li>
+  <li><a href="./topic">Topic mode</a> - extends and include from store</li>
 </ul>'
     }
   }

diff --git a/examples/templates/topics/nav.html b/examples/templates/topics/nav.html
@@ -1 +1 @@
-<nav><a href="/">Home</a> | Page (from store)</nav>
+<nav><a href="./">Home</a> | Page (from store)</nav>
diff --git a/src/engine.rs b/src/engine.rs
@@ -26,6 +26,19 @@ use crate::logging::log_error;
 use crate::stdlib::load_http_nu_stdlib;
 use crate::Error;
 
+/// CLI options exposed to scripts as the `$HTTP_NU` const
+#[derive(Clone, Default)]
+pub struct HttpNuOptions {
+    pub dev: bool,
+    pub datastar: bool,
+    pub watch: bool,
+    pub store: Option<String>,
+    pub topic: Option<String>,
+    pub expose: Option<String>,
+    pub tls: Option<String>,
+    pub services: bool,
+}
+
 #[derive(Clone)]
 pub struct Engine {
     pub state: EngineState,
@@ -55,18 +68,30 @@ impl Engine {
         })
     }
 
-    /// Sets `$env.HTTP_NU` with server configuration for stdlib modules
-    pub fn set_http_nu_env(&mut self, dev: bool) -> Result<(), Error> {
-        let mut stack = Stack::new();
+    /// Sets `$HTTP_NU` const with server configuration for stdlib modules
+    pub fn set_http_nu_const(&mut self, options: &HttpNuOptions) -> Result<(), Error> {
         let span = Span::unknown();
+        let opt_str = |v: &Option<String>| match v {
+            Some(s) => Value::string(s, span),
+            None => Value::nothing(span),
+        };
         let record = Value::record(
             nu_protocol::record! {
-                "dev" => Value::bool(dev, span),
+                "dev" => Value::bool(options.dev, span),
+                "datastar" => Value::bool(options.datastar, span),
+                "watch" => Value::bool(options.watch, span),
+                "store" => opt_str(&options.store),
+                "topic" => opt_str(&options.topic),
+                "expose" => opt_str(&options.expose),
+                "tls" => opt_str(&options.tls),
+                "services" => Value::bool(options.services, span),
             },
             span,
         );
-        stack.add_env_var("HTTP_NU".to_string(), record);
-        self.state.merge_env(&mut stack)?;
+        let mut working_set = StateWorkingSet::new(&self.state);
+        let var_id = working_set.add_variable(b"$HTTP_NU".into(), span, Type::record(), false);
+        working_set.set_variable_const_val(var_id, record);
+        self.state.merge_delta(working_set.render())?;
         Ok(())
     }
Original file line number	Diff line number	Diff line change
		@@ -1 +1 @@
		<nav><a href="/">Home</a> \| Page (from disk)</nav>
		<nav><a href="./">Home</a> \| Page (from disk)</nav>
Original file line number	Diff line number	Diff line change
		@@ -1 +1 @@
		<nav><a href="/">Home</a> \| Page (from store)</nav>
		<nav><a href="./">Home</a> \| Page (from store)</nav>