From e8fcb84881d6d76ecff61310ba5ee5509b1b893d Mon Sep 17 00:00:00 2001
From: dave horner <dhorner@white.>
Date: Mon, 17 Nov 2025 18:54:47 -0500
Subject: [PATCH 1/2] feat(viewer): add .vm file support to seamlessly load and
 render both .vm and Rhai script files.

- Update file watcher and script thread to pass both file contents and path.
- Detect .vm files and parse them as flat text math trees using Context::from_text, wrapping the result in a ScriptContext.
---
 demos/viewer/src/script.rs  | 27 ++++++++++++++++++++++-----
 demos/viewer/src/watcher.rs |  7 ++++---
 2 files changed, 26 insertions(+), 8 deletions(-)

diff --git a/demos/viewer/src/script.rs b/demos/viewer/src/script.rs
index e2538a16..90ae7bc8 100644
--- a/demos/viewer/src/script.rs
+++ b/demos/viewer/src/script.rs
@@ -6,17 +6,34 @@ use std::sync::{Arc, Mutex};
 
 /// Receives scripts and executes them with Fidget
 pub(crate) fn rhai_script_thread(
-    rx: Receiver<String>,
+    rx: Receiver<(String, String)>,
     tx: Sender<Result<ScriptContext, String>>,
 ) -> Result<()> {
     let mut engine = Engine::new();
 
     loop {
-        let script = rx.recv()?;
+        let (script, path) = rx.recv()?;
         debug!("rhai script thread received script");
-        let r = engine.run(&script).map_err(|e| e.to_string());
-        debug!("rhai script thread is sending result to render thread");
-        tx.send(r)?;
+        if path.ends_with(".vm") {
+            // Parse as flat text math tree
+            use fidget::context::Context;
+            use std::io::Cursor;
+            match Context::from_text(Cursor::new(&script)) {
+                Ok((ctx, node)) => {
+                    let tree = ctx.export(node).unwrap();
+                    let mut sc = ScriptContext::new();
+                    sc.shapes.push(DrawShape { tree, color_rgb: [255, 255, 255] });
+                    tx.send(Ok(sc))?;
+                }
+                Err(e) => {
+                    tx.send(Err(format!(".vm parse error: {e}")))?;
+                }
+            }
+        } else {
+            let r = engine.run(&script).map_err(|e| e.to_string());
+            debug!("rhai script thread is sending result to render thread");
+            tx.send(r)?;
+        }
     }
 }
 
diff --git a/demos/viewer/src/watcher.rs b/demos/viewer/src/watcher.rs
index 9371b6fc..0670ecc9 100644
--- a/demos/viewer/src/watcher.rs
+++ b/demos/viewer/src/watcher.rs
@@ -7,14 +7,15 @@ use std::path::Path;
 pub(crate) fn file_watcher_thread(
     path: &Path,
     rx: Receiver<()>,
-    tx: Sender<String>,
+    tx: Sender<(String, String)>,
 ) -> Result<()> {
     let read_file = || -> Result<String> {
         let out = String::from_utf8(std::fs::read(path)?).unwrap();
         Ok(out)
     };
     let mut contents = read_file()?;
-    tx.send(contents.clone())?;
+    let path_str = path.to_string_lossy().to_string();
+    tx.send((contents.clone(), path_str.clone()))?;
 
     loop {
         // Wait for a file change notification
@@ -31,7 +32,7 @@ pub(crate) fn file_watcher_thread(
         if contents != new_contents {
             contents = new_contents;
             debug!("file contents changed!");
-            tx.send(contents.clone())?;
+            tx.send((contents.clone(), path_str.clone()))?;
         }
     }
 }

From c8321bb78f43c3927412d12c25a9aca350fce642 Mon Sep 17 00:00:00 2001
From: dave horner <dhorner@white.>
Date: Mon, 17 Nov 2025 19:17:54 -0500
Subject: [PATCH 2/2] feat(env-fitler): allow set RUST_LOG=error to just print
 errors, silencing the underlying lib info/debug.

---
 demos/viewer/Cargo.toml  | 1 +
 demos/viewer/src/main.rs | 4 ++--
 2 files changed, 3 insertions(+), 2 deletions(-)

diff --git a/demos/viewer/Cargo.toml b/demos/viewer/Cargo.toml
index 54070464..d3d4709f 100644
--- a/demos/viewer/Cargo.toml
+++ b/demos/viewer/Cargo.toml
@@ -18,6 +18,7 @@ zerocopy.workspace = true
 
 fidget.workspace = true
 workspace-hack.workspace = true
+tracing-subscriber = { version = "0.3.20", features = ["env-filter"] }
 
 [features]
 default = ["jit"]
diff --git a/demos/viewer/src/main.rs b/demos/viewer/src/main.rs
index 51d09c7a..47f0ac0d 100644
--- a/demos/viewer/src/main.rs
+++ b/demos/viewer/src/main.rs
@@ -5,7 +5,6 @@ use eframe::{
     egui,
     egui_wgpu::{self, wgpu},
 };
-use env_logger::Env;
 use log::{debug, error, info};
 use nalgebra::Point2;
 use notify::{Event, EventKind, Watcher};
@@ -223,7 +222,8 @@ fn render_3d<F: fidget::eval::Function + fidget::render::RenderHints>(
 }
 
 fn main() -> Result<(), Box<dyn Error>> {
-    env_logger::Builder::from_env(Env::default().default_filter_or("info"))
+    tracing_subscriber::fmt()
+        .with_env_filter(tracing_subscriber::EnvFilter::from_default_env())
         .init();
     let args = Args::parse();