From 0753ea2b9e10b0f5030b05e84cd8490cc9ec7b34 Mon Sep 17 00:00:00 2001
From: Brian Cully <bjc@spork.org>
Date: Sat, 23 Aug 2025 13:05:07 -0400
Subject: highlight running code

---
 main.css   |  4 ++++
 main.mjs   | 21 +++++++++++++++++++++
 src/lib.rs | 28 ++++++++++++++++++++++------
 3 files changed, 47 insertions(+), 6 deletions(-)

diff --git a/main.css b/main.css
index 15d721d..7a032cc 100644
--- a/main.css
+++ b/main.css
@@ -7,6 +7,10 @@ textarea {
     height: 25ex;
 }
 
+#wordlist .ip {
+    background-color: yellow;
+}
+
 x-bytecode {
     display: block;
 }
diff --git a/main.mjs b/main.mjs
index bcb7f0a..7bc2ba4 100644
--- a/main.mjs
+++ b/main.mjs
@@ -14,6 +14,12 @@ function wordlistElts(wordlist) {
     })
 }
 
+function selectorForIP(word, offset) {
+    const sel = `#wordlist x-bytecode[x-index='${word}'] x-op[x-index='${offset}']`;
+    console.debug('using sel', sel);
+    return sel;
+}
+
 async function loaded() {
     console.debug('running init');
     const mod = await init();
@@ -39,10 +45,25 @@ async function loaded() {
         if (res) {
             const wordlist = wordlistElts(interp.wordlist());
             wordlist.forEach(elt => wordlistContainer.appendChild(elt));
+            const sel = selectorForIP(0, 0);
+            document.querySelectorAll(sel).forEach(e => {
+                e.classList.add('ip')
+            });
         }
     };
     document.querySelector('#tick').onclick = e => {
         console.debug('tick clicked', e);
+        interp.tick();
+        console.info('callstack', interp.callstack());
+        console.info('stack', interp.stack());
+
+        const { word, offset } = interp.ip();
+        console.info('ip', word, offset);
+        document.querySelectorAll('#wordlist .ip').forEach(e => e.classList.remove('ip'));
+        const sel = selectorForIP(word, offset);
+        document.querySelectorAll(sel).forEach(e => {
+            e.classList.add('ip')
+        });
     };
     document.querySelector('#run').onclick = e => {
         console.debug('run clicked', e);
diff --git a/src/lib.rs b/src/lib.rs
index 32a8ffc..840a86c 100755
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -10,6 +10,12 @@ pub struct ExportedInstructionPointer {
     pub offset: usize,
 }
 
+impl From<&forth::interp::InstructionPointer> for ExportedInstructionPointer {
+    fn from(ip: &forth::interp::InstructionPointer) -> Self {
+        Self { word: ip.word, offset: ip.offset }
+    }
+}
+
 // wasm can't wrap Vec<Vec<String>>, so we need a custom type
 // - 23-aug-2025
 #[wasm_bindgen]
@@ -67,8 +73,12 @@ impl ExportedInterp {
         true
     }
 
-    pub fn tick(&mut self) {
+    pub fn tick(&mut self) -> Result<bool, String> {
+        let Some(interp) = &mut self.i else {
+            return Err("no interpreter".to_string())
+        };
         info!("executing single instruction");
+        interp.tick().or_else(|err| Err(format!("runtime error: {:?}", err)))
     }
 
     pub fn run(&mut self) -> Result<usize, String> {
@@ -98,15 +108,21 @@ impl ExportedInterp {
         interp.wordlist.iter().map(|bc| ExportedByteCode::from_bc(bc)).collect()
     }
 
+    pub fn callstack(&self) -> Vec<ExportedInstructionPointer> {
+        let Some(interp) = &self.i else {
+            return vec![]
+        };
+        info!("callstack: ‘{:?}’", interp.callstack);
+        interp.callstack.0.iter()
+            .map(|ip| ip.into())
+            .collect()
+    }
+
     pub fn ip(&self) -> ExportedInstructionPointer {
         let Some(interp) = self.i.as_ref() else {
             return ExportedInstructionPointer { word: 0, offset: 0 }
         };
-
-        ExportedInstructionPointer {
-            word: interp.ip.word,
-            offset: interp.ip.offset,
-        }
+        (&interp.ip).into()
     }
 }
 
-- 
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