Add new syntax support to walker.

Author: goto-bus-stop

test/index.js

@@ -1,5 +1,6 @@
 var test = require('tape')
 var acorn = require('../')
+var walk = require('../walk')
 var baseAcorn = require('acorn')
 
 test('parses object spread syntax', function (t) {
@@ -85,3 +86,20 @@ test('supports dynamic import() with sourceType: module', function (t) {
   })
   t.end()
 })
+
+test('walk supports plugin syntax', function (t) {
+  var ast = acorn.parse(
+    'async function* a() { try { await import(xyz); } catch { for await (x of null) {} } yield import.meta.url }',
+    { sourceType: 'module' }
+  )
+  t.plan(2)
+  walk.simple(ast, {
+    Import () {
+      t.pass('import()')
+    },
+    MetaProperty () {
+      t.pass('import.meta')
+    }
+  })
+  t.end()
+})

walk.js

@@ -1,3 +1,63 @@
+var xtend = require('xtend')
 var walk = require('acorn/dist/walk')
 
-module.exports = walk
+var base = xtend(walk.base, {
+  Import: function () {},
+  // pending https://github.com/acornjs/acorn/pull/705
+  CatchClause: function (node, st, c) {
+    if (node.param) c(node.param, st, 'Pattern')
+    c(node.body, st, 'ScopeBody')
+  }
+})
+
+function simple (node, visitors, baseVisitor, state, override) {
+  return walk.simple(node, visitors, baseVisitor || base, state, override)
+}
+
+function ancestor (node, visitors, baseVisitor, state) {
+  return walk.ancestor(node, visitors, baseVisitor || base, state)
+}
+
+function recursive (node, state, funcs, baseVisitor, override) {
+  return walk.recursive(node, state, funcs, baseVisitor || base, override)
+}
+
+function full (node, callback, baseVisitor, state, override) {
+  return walk.full(node, callback, baseVisitor || base, state, override)
+}
+
+function fullAncestor (node, callback, baseVisitor, state) {
+  return walk.fullAncestor(node, callback, baseVisitor || base, state)
+}
+
+function findNodeAt (node, start, end, test, baseVisitor, state) {
+  return walk.findNodeAt(node, start, end, test, baseVisitor || base, state)
+}
+
+function findNodeAround (node, pos, test, baseVisitor, state) {
+  return walk.findNodeAround(node, pos, test, baseVisitor || base, state)
+}
+
+function findNodeAfter (node, pos, test, baseVisitor, state) {
+  return walk.findNodeAfter(node, pos, test, baseVisitor || base, state)
+}
+
+function findNodeBefore (node, pos, test, baseVisitor, state) {
+  return walk.findNodeBefore(node, pos, test, baseVisitor || base, state)
+}
+
+function make (funcs, baseVisitor) {
+  return walk.make(funcs, baseVisitor || base)
+}
+
+exports.simple = simple
+exports.ancestor = ancestor
+exports.recursive = recursive
+exports.full = full
+exports.fullAncestor = fullAncestor
+exports.findNodeAt = findNodeAt
+exports.findNodeAround = findNodeAround
+exports.findNodeAfter = findNodeAfter
+exports.findNodeBefore = findNodeBefore
+exports.make = make
+exports.base = base