sebmarkbage · August 11, 2020 04:03 · May 15, 2017 · May 15, 2017 · May 15, 2017 · May 15, 2017
diff --git a/Custom Stack Frames Semantics.md b/Custom Stack Frames Semantics.md
@@ -4,7 +4,7 @@ The current execution context has a "custom stack" context with two internal slo
 
 `console.endStack` - Clear the `[[Custom Stack Start]]` and `[[Custom Stack Override]]` stacks.
 
-`console.log`, `console.warn`, `console.error` etc. - For any function that logs stacks associated with the call. If there is something in the `[[Custom Stack Start]]` slot. Find the current stack from the current execution context. Find the common ancestor between `[[Custom Stack Start]]` and the current stack. Remove all the common ancestors. Replace them with `[[Custom Stack Override]]` in the root of the stack.
+`console.trace`, `console.warn`, `console.error` etc. - For any function that logs stacks associated with the call. If there is something in the `[[Custom Stack Start]]` slot. Find the current stack from the current execution context. Find the common ancestor between `[[Custom Stack Start]]` and the current stack. Remove all the common ancestors. Replace them with `[[Custom Stack Override]]` in the root of the stack.
 
 If a break point happens, e.g. due to an error being thrown, `debugger` call or custom break points. If there is something in the  `[[Custom Stack Start]]` slot, use the same mechanism as `console.log` to determine the current stack to visualize in a debugger instead of the native stack. The `scope` property contains an object. Every "own" property is considered to be a variable with that name in scope of that stack frame. Useful for debugging.
 

diff --git a/API Semantics.md → Custom Stack Frames Semantics.md b/API Semantics.md → Custom Stack Frames Semantics.md
diff --git a/Examples.js → Example.js b/Examples.js → Example.js
@@ -9,7 +9,7 @@ function bar(x) {
     stack: [
       {
         name: 'bar',
-        fileName: 'bar.js',
+        fileName: 'Bar.js',
         lineNumber: 10,
         columnNumber: 5,
       }
@@ -29,5 +29,5 @@ var continuation = bar(false);
 invokeCallback(continuation);
 // Logs:
 // You must provide the x argument.
-//    at foo (Examples.js:3:4)
-//    at bar (bar.js:10:5)
+//    at foo (Example.js:3:4)
+//    at bar (Bar.js:10:5)
diff --git a/Semantics.md → API Semantics.md b/Semantics.md → API Semantics.md
diff --git a/Examples.js b/Examples.js
@@ -0,0 +1,33 @@
+function foo(x) {
+  if (!x) {
+    console.warn('You must provide the x argument.');
+  }
+}
+
+function bar(x) {
+  return {
+    stack: [
+      {
+        name: 'bar',
+        fileName: 'bar.js',
+        lineNumber: 10,
+        columnNumber: 5,
+      }
+    ],
+    callback: foo.bind(null, x)
+  };
+}
+
+function invokeCallback(continuation) {
+  console.stack(continuation.stack);
+  continuation.callback();
+  console.endStack();
+}
+
+var continuation = bar(false);
+
+invokeCallback(continuation);
+// Logs:
+// You must provide the x argument.
+//    at foo (Examples.js:3:4)
+//    at bar (bar.js:10:5)
diff --git a/API.js b/API.js
@@ -1,12 +1,16 @@
+type FrameScope = {
+  [key:string]: mixed
+};
 type StackFrame = {
   name?: string,
   fileName?: string,
   lineNumber?: number,
-  columnNumber?: number
+  columnNumber?: number,
+  scope?: FrameScope
 };
 type StackFrames = Array<StackFrame>;
 type ExtendedConsoleAPI = {
   ...ConsoleAPI,
   stack(frames: StackFrames) : void,
-  endStack() : void,
+  endStack() : void
 };
diff --git a/Semantics.md b/Semantics.md
@@ -4,4 +4,8 @@ The current execution context has a "custom stack" context with two internal slo
 
 `console.endStack` - Clear the `[[Custom Stack Start]]` and `[[Custom Stack Override]]` stacks.
 
-`console.log`, `console.warn`, `console.error` etc. - For any function that logs stacks associated with the call. If there is something in the `[[Custom Stack Start]]` slot. Find the current stack from the current execution context. Find the common ancestor between `[[Custom Stack Start]]` and the current stack. Remove all the common ancestors and replace them with [[Custom Stack Override]].
+`console.log`, `console.warn`, `console.error` etc. - For any function that logs stacks associated with the call. If there is something in the `[[Custom Stack Start]]` slot. Find the current stack from the current execution context. Find the common ancestor between `[[Custom Stack Start]]` and the current stack. Remove all the common ancestors. Replace them with `[[Custom Stack Override]]` in the root of the stack.
+
+If a break point happens, e.g. due to an error being thrown, `debugger` call or custom break points. If there is something in the  `[[Custom Stack Start]]` slot, use the same mechanism as `console.log` to determine the current stack to visualize in a debugger instead of the native stack. The `scope` property contains an object. Every "own" property is considered to be a variable with that name in scope of that stack frame. Useful for debugging.
+
+TODO: Consider what should happen to `new Error().stack` if the error is created within a custom scope.
diff --git a/API.js b/API.js
@@ -0,0 +1,12 @@
+type StackFrame = {
+  name?: string,
+  fileName?: string,
+  lineNumber?: number,
+  columnNumber?: number
+};
+type StackFrames = Array<StackFrame>;
+type ExtendedConsoleAPI = {
+  ...ConsoleAPI,
+  stack(frames: StackFrames) : void,
+  endStack() : void,
+};
diff --git a/Semantics.md b/Semantics.md
@@ -0,0 +1,7 @@
+The current execution context has a "custom stack" context with two internal slots `[[Custom Stack Start]]` and `[[Custom Stack Override]]`.
+
+`console.stack` - Assert that the first argument is an array. Store the current stack frame context at the VM level (same as `new Error().stack`) in the current execution context's `[[Custom Stack Start]]` slot. Store the first argument array in the current execution context's `[[Custom Stack Override]]` slot.
+
+`console.endStack` - Clear the `[[Custom Stack Start]]` and `[[Custom Stack Override]]` stacks.
+
+`console.log`, `console.warn`, `console.error` etc. - For any function that logs stacks associated with the call. If there is something in the `[[Custom Stack Start]]` slot. Find the current stack from the current execution context. Find the common ancestor between `[[Custom Stack Start]]` and the current stack. Remove all the common ancestors and replace them with [[Custom Stack Override]].