hotkey to select error origin

src/ast_utils.js

@@ -145,8 +145,9 @@ export const find_node = (node, pred) => {
     )
 }
 
-// TODO refactor, have explicit information if node is error origin, without
-// guessing. See also color.js
+// TODO refactor, at eval.js we have explicit information if node is error
+// origin, without guessing. See also color.js
+// TODO result is ok, but value is rejected promise
 // TODO check if return result is null and throw early
 export const find_error_origin_node = node =>
   find_node(

src/calltree.js

@@ -836,6 +836,42 @@ const select_arguments = (state, with_focus = true) => {
   }
 }
 
+const select_error = state => {
+  const node = [
+    state.current_calltree_node,
+    state.active_calltree_node,
+    root_calltree_node(state),
+    // TODO deferred calls???
+  ].find(n => n != null && !n.ok)
+  
+  if(node == null) {
+    return {state, effects: [{type: 'set_status', args: ['no error found']}]}
+  }
+
+  const error_origin = find_node(node, n =>
+    !n.ok 
+    && (
+      n.children == null || n.children.every(c => c.ok)
+    )
+  )
+
+  if(error_origin == null) {
+    throw new Error('illegal state: error origin not found')
+  }
+
+  const next = expand_path(add_frame(state, error_origin), error_origin)
+  const frame = active_frame(next)
+  const error_node = find_error_origin_node(frame)
+
+  return {
+    state: set_location(next, {
+      module: calltree_node_loc(error_origin).module, 
+      index: error_node.index
+    }),
+    effects: {type: 'set_focus'}
+  }
+}
+
 const navigate_logs_increment = (state, increment) => {
   if(state.logs.logs.length == 0) {
     return {state}
@@ -875,6 +911,7 @@ export const calltree_commands = {
   click,
   select_return_value,
   select_arguments,
+  select_error,
   navigate_logs_position,
   navigate_logs_increment,
 }

src/editor/calltree.js

@@ -39,6 +39,10 @@ export class CallTree {
         exec('calltree.select_arguments')
       }
 
+      if(e.key == 'e') {
+        exec('calltree.select_error')
+      }
+
       if(e.key == 'r' || e.key == 'Enter') {
         exec('calltree.select_return_value')
       }

src/editor/ui.js

@@ -307,6 +307,7 @@ export class UI {
       ['Step out of call', 'Ctrl-o', '\\o'],
       ['When in call tree view, jump to return statement', 'Enter'],
       ['When in call tree view, jump to function arguments', 'a'],
+      ['When in call tree view, jump to error origin', 'e'],
       ['Clear IO trace', 'F6'],
       ['(Re)open run window (F7)', 'F7'],
     ]

test/test.js

@@ -2375,6 +2375,24 @@ const y = x()`
     assert_equal(s3.value_explorer.result, {ok: true, value: ["1"]})
   }),
 
+  test('select_error', () => {
+    const code = `
+      const deep = x => {
+        if(x == 10) {
+          throw new Error()
+        } else {
+          deep(x + 1)
+        }
+      }
+
+      deep(0)
+    `
+    const i = test_initial_state(code, code.indexOf('deep(x + 1)'))
+    const {state: found_err_state, effects} = COMMANDS.calltree.select_error(i)
+    assert_equal(found_err_state.active_calltree_node.args, [10])
+    assert_equal(current_cursor_position(found_err_state), code.indexOf('throw'))
+  }),
+
   test('move_cursor arguments', () => {
     const code = `
       const x = (a, b) => { }