438 lines
14 KiB
JavaScript
438 lines
14 KiB
JavaScript
// AST walker module for ESTree compatible trees
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// A simple walk is one where you simply specify callbacks to be
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// called on specific nodes. The last two arguments are optional. A
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// simple use would be
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//
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// walk.simple(myTree, {
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// Expression: function(node) { ... }
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// });
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//
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// to do something with all expressions. All ESTree node types
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// can be used to identify node types, as well as Expression and
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// Statement, which denote categories of nodes.
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//
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// The base argument can be used to pass a custom (recursive)
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// walker, and state can be used to give this walked an initial
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// state.
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function simple(node, visitors, baseVisitor, state, override) {
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if (!baseVisitor) { baseVisitor = base
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; }(function c(node, st, override) {
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var type = override || node.type;
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baseVisitor[type](node, st, c);
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if (visitors[type]) { visitors[type](node, st); }
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})(node, state, override);
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}
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// An ancestor walk keeps an array of ancestor nodes (including the
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// current node) and passes them to the callback as third parameter
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// (and also as state parameter when no other state is present).
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function ancestor(node, visitors, baseVisitor, state, override) {
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var ancestors = [];
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if (!baseVisitor) { baseVisitor = base
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; }(function c(node, st, override) {
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var type = override || node.type;
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var isNew = node !== ancestors[ancestors.length - 1];
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if (isNew) { ancestors.push(node); }
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baseVisitor[type](node, st, c);
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if (visitors[type]) { visitors[type](node, st || ancestors, ancestors); }
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if (isNew) { ancestors.pop(); }
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})(node, state, override);
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}
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// A recursive walk is one where your functions override the default
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// walkers. They can modify and replace the state parameter that's
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// threaded through the walk, and can opt how and whether to walk
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// their child nodes (by calling their third argument on these
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// nodes).
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function recursive(node, state, funcs, baseVisitor, override) {
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var visitor = funcs ? make(funcs, baseVisitor || undefined) : baseVisitor
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;(function c(node, st, override) {
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visitor[override || node.type](node, st, c);
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})(node, state, override);
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}
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function makeTest(test) {
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if (typeof test === "string")
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{ return function (type) { return type === test; } }
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else if (!test)
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{ return function () { return true; } }
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else
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{ return test }
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}
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var Found = function Found(node, state) { this.node = node; this.state = state; };
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// A full walk triggers the callback on each node
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function full(node, callback, baseVisitor, state, override) {
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if (!baseVisitor) { baseVisitor = base; }
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var last
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;(function c(node, st, override) {
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var type = override || node.type;
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baseVisitor[type](node, st, c);
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if (last !== node) {
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callback(node, st, type);
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last = node;
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}
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})(node, state, override);
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}
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// An fullAncestor walk is like an ancestor walk, but triggers
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// the callback on each node
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function fullAncestor(node, callback, baseVisitor, state) {
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if (!baseVisitor) { baseVisitor = base; }
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var ancestors = [], last
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;(function c(node, st, override) {
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var type = override || node.type;
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var isNew = node !== ancestors[ancestors.length - 1];
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if (isNew) { ancestors.push(node); }
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baseVisitor[type](node, st, c);
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if (last !== node) {
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callback(node, st || ancestors, ancestors, type);
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last = node;
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}
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if (isNew) { ancestors.pop(); }
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})(node, state);
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}
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// Find a node with a given start, end, and type (all are optional,
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// null can be used as wildcard). Returns a {node, state} object, or
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// undefined when it doesn't find a matching node.
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function findNodeAt(node, start, end, test, baseVisitor, state) {
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if (!baseVisitor) { baseVisitor = base; }
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test = makeTest(test);
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try {
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(function c(node, st, override) {
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var type = override || node.type;
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if ((start == null || node.start <= start) &&
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(end == null || node.end >= end))
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{ baseVisitor[type](node, st, c); }
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if ((start == null || node.start === start) &&
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(end == null || node.end === end) &&
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test(type, node))
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{ throw new Found(node, st) }
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})(node, state);
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} catch (e) {
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if (e instanceof Found) { return e }
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throw e
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}
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}
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// Find the innermost node of a given type that contains the given
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// position. Interface similar to findNodeAt.
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function findNodeAround(node, pos, test, baseVisitor, state) {
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test = makeTest(test);
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if (!baseVisitor) { baseVisitor = base; }
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try {
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(function c(node, st, override) {
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var type = override || node.type;
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if (node.start > pos || node.end < pos) { return }
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baseVisitor[type](node, st, c);
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if (test(type, node)) { throw new Found(node, st) }
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})(node, state);
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} catch (e) {
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if (e instanceof Found) { return e }
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throw e
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}
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}
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// Find the outermost matching node after a given position.
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function findNodeAfter(node, pos, test, baseVisitor, state) {
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test = makeTest(test);
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if (!baseVisitor) { baseVisitor = base; }
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try {
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(function c(node, st, override) {
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if (node.end < pos) { return }
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var type = override || node.type;
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if (node.start >= pos && test(type, node)) { throw new Found(node, st) }
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baseVisitor[type](node, st, c);
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})(node, state);
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} catch (e) {
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if (e instanceof Found) { return e }
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throw e
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}
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}
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// Find the outermost matching node before a given position.
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function findNodeBefore(node, pos, test, baseVisitor, state) {
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test = makeTest(test);
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if (!baseVisitor) { baseVisitor = base; }
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var max
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;(function c(node, st, override) {
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if (node.start > pos) { return }
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var type = override || node.type;
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if (node.end <= pos && (!max || max.node.end < node.end) && test(type, node))
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{ max = new Found(node, st); }
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baseVisitor[type](node, st, c);
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})(node, state);
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return max
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}
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// Used to create a custom walker. Will fill in all missing node
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// type properties with the defaults.
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function make(funcs, baseVisitor) {
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var visitor = Object.create(baseVisitor || base);
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for (var type in funcs) { visitor[type] = funcs[type]; }
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return visitor
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}
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function skipThrough(node, st, c) { c(node, st); }
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function ignore(_node, _st, _c) {}
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// Node walkers.
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var base = {};
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base.Program = base.BlockStatement = base.StaticBlock = function (node, st, c) {
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for (var i = 0, list = node.body; i < list.length; i += 1)
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{
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var stmt = list[i];
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c(stmt, st, "Statement");
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}
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};
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base.Statement = skipThrough;
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base.EmptyStatement = ignore;
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base.ExpressionStatement = base.ParenthesizedExpression = base.ChainExpression =
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function (node, st, c) { return c(node.expression, st, "Expression"); };
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base.IfStatement = function (node, st, c) {
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c(node.test, st, "Expression");
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c(node.consequent, st, "Statement");
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if (node.alternate) { c(node.alternate, st, "Statement"); }
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};
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base.LabeledStatement = function (node, st, c) { return c(node.body, st, "Statement"); };
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base.BreakStatement = base.ContinueStatement = ignore;
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base.WithStatement = function (node, st, c) {
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c(node.object, st, "Expression");
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c(node.body, st, "Statement");
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};
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base.SwitchStatement = function (node, st, c) {
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c(node.discriminant, st, "Expression");
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for (var i = 0, list = node.cases; i < list.length; i += 1) {
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var cs = list[i];
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c(cs, st);
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}
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};
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base.SwitchCase = function (node, st, c) {
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if (node.test) { c(node.test, st, "Expression"); }
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for (var i = 0, list = node.consequent; i < list.length; i += 1)
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{
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var cons = list[i];
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c(cons, st, "Statement");
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}
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};
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base.ReturnStatement = base.YieldExpression = base.AwaitExpression = function (node, st, c) {
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if (node.argument) { c(node.argument, st, "Expression"); }
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};
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base.ThrowStatement = base.SpreadElement =
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function (node, st, c) { return c(node.argument, st, "Expression"); };
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base.TryStatement = function (node, st, c) {
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c(node.block, st, "Statement");
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if (node.handler) { c(node.handler, st); }
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if (node.finalizer) { c(node.finalizer, st, "Statement"); }
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};
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base.CatchClause = function (node, st, c) {
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if (node.param) { c(node.param, st, "Pattern"); }
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c(node.body, st, "Statement");
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};
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base.WhileStatement = base.DoWhileStatement = function (node, st, c) {
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c(node.test, st, "Expression");
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c(node.body, st, "Statement");
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};
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base.ForStatement = function (node, st, c) {
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if (node.init) { c(node.init, st, "ForInit"); }
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if (node.test) { c(node.test, st, "Expression"); }
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if (node.update) { c(node.update, st, "Expression"); }
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c(node.body, st, "Statement");
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};
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base.ForInStatement = base.ForOfStatement = function (node, st, c) {
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c(node.left, st, "ForInit");
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c(node.right, st, "Expression");
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c(node.body, st, "Statement");
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};
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base.ForInit = function (node, st, c) {
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if (node.type === "VariableDeclaration") { c(node, st); }
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else { c(node, st, "Expression"); }
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};
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base.DebuggerStatement = ignore;
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base.FunctionDeclaration = function (node, st, c) { return c(node, st, "Function"); };
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base.VariableDeclaration = function (node, st, c) {
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for (var i = 0, list = node.declarations; i < list.length; i += 1)
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{
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var decl = list[i];
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c(decl, st);
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}
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};
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base.VariableDeclarator = function (node, st, c) {
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c(node.id, st, "Pattern");
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if (node.init) { c(node.init, st, "Expression"); }
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};
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base.Function = function (node, st, c) {
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if (node.id) { c(node.id, st, "Pattern"); }
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for (var i = 0, list = node.params; i < list.length; i += 1)
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{
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var param = list[i];
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c(param, st, "Pattern");
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}
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c(node.body, st, node.expression ? "Expression" : "Statement");
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};
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base.Pattern = function (node, st, c) {
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if (node.type === "Identifier")
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{ c(node, st, "VariablePattern"); }
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else if (node.type === "MemberExpression")
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{ c(node, st, "MemberPattern"); }
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else
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{ c(node, st); }
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};
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base.VariablePattern = ignore;
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base.MemberPattern = skipThrough;
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base.RestElement = function (node, st, c) { return c(node.argument, st, "Pattern"); };
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base.ArrayPattern = function (node, st, c) {
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for (var i = 0, list = node.elements; i < list.length; i += 1) {
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var elt = list[i];
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if (elt) { c(elt, st, "Pattern"); }
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}
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};
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base.ObjectPattern = function (node, st, c) {
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for (var i = 0, list = node.properties; i < list.length; i += 1) {
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var prop = list[i];
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if (prop.type === "Property") {
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if (prop.computed) { c(prop.key, st, "Expression"); }
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c(prop.value, st, "Pattern");
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} else if (prop.type === "RestElement") {
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c(prop.argument, st, "Pattern");
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}
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}
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};
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base.Expression = skipThrough;
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base.ThisExpression = base.Super = base.MetaProperty = ignore;
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base.ArrayExpression = function (node, st, c) {
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for (var i = 0, list = node.elements; i < list.length; i += 1) {
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var elt = list[i];
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if (elt) { c(elt, st, "Expression"); }
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}
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};
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base.ObjectExpression = function (node, st, c) {
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for (var i = 0, list = node.properties; i < list.length; i += 1)
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{
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var prop = list[i];
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c(prop, st);
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}
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};
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base.FunctionExpression = base.ArrowFunctionExpression = base.FunctionDeclaration;
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base.SequenceExpression = function (node, st, c) {
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for (var i = 0, list = node.expressions; i < list.length; i += 1)
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{
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var expr = list[i];
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c(expr, st, "Expression");
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}
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};
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base.TemplateLiteral = function (node, st, c) {
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for (var i = 0, list = node.quasis; i < list.length; i += 1)
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{
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var quasi = list[i];
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c(quasi, st);
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}
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for (var i$1 = 0, list$1 = node.expressions; i$1 < list$1.length; i$1 += 1)
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{
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var expr = list$1[i$1];
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c(expr, st, "Expression");
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}
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};
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base.TemplateElement = ignore;
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base.UnaryExpression = base.UpdateExpression = function (node, st, c) {
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c(node.argument, st, "Expression");
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};
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base.BinaryExpression = base.LogicalExpression = function (node, st, c) {
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c(node.left, st, "Expression");
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c(node.right, st, "Expression");
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};
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base.AssignmentExpression = base.AssignmentPattern = function (node, st, c) {
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c(node.left, st, "Pattern");
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c(node.right, st, "Expression");
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};
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base.ConditionalExpression = function (node, st, c) {
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c(node.test, st, "Expression");
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c(node.consequent, st, "Expression");
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c(node.alternate, st, "Expression");
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};
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base.NewExpression = base.CallExpression = function (node, st, c) {
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c(node.callee, st, "Expression");
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if (node.arguments)
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{ for (var i = 0, list = node.arguments; i < list.length; i += 1)
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{
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var arg = list[i];
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c(arg, st, "Expression");
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} }
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};
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base.MemberExpression = function (node, st, c) {
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c(node.object, st, "Expression");
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if (node.computed) { c(node.property, st, "Expression"); }
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};
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base.ExportNamedDeclaration = base.ExportDefaultDeclaration = function (node, st, c) {
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if (node.declaration)
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{ c(node.declaration, st, node.type === "ExportNamedDeclaration" || node.declaration.id ? "Statement" : "Expression"); }
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if (node.source) { c(node.source, st, "Expression"); }
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};
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base.ExportAllDeclaration = function (node, st, c) {
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if (node.exported)
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{ c(node.exported, st); }
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c(node.source, st, "Expression");
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};
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base.ImportDeclaration = function (node, st, c) {
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for (var i = 0, list = node.specifiers; i < list.length; i += 1)
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{
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var spec = list[i];
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c(spec, st);
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}
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c(node.source, st, "Expression");
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};
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base.ImportExpression = function (node, st, c) {
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c(node.source, st, "Expression");
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};
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base.ImportSpecifier = base.ImportDefaultSpecifier = base.ImportNamespaceSpecifier = base.Identifier = base.PrivateIdentifier = base.Literal = ignore;
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base.TaggedTemplateExpression = function (node, st, c) {
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c(node.tag, st, "Expression");
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c(node.quasi, st, "Expression");
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};
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base.ClassDeclaration = base.ClassExpression = function (node, st, c) { return c(node, st, "Class"); };
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base.Class = function (node, st, c) {
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if (node.id) { c(node.id, st, "Pattern"); }
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if (node.superClass) { c(node.superClass, st, "Expression"); }
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c(node.body, st);
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};
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base.ClassBody = function (node, st, c) {
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for (var i = 0, list = node.body; i < list.length; i += 1)
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{
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var elt = list[i];
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c(elt, st);
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}
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};
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base.MethodDefinition = base.PropertyDefinition = base.Property = function (node, st, c) {
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if (node.computed) { c(node.key, st, "Expression"); }
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if (node.value) { c(node.value, st, "Expression"); }
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};
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export { ancestor, base, findNodeAfter, findNodeAround, findNodeAt, findNodeBefore, full, fullAncestor, make, recursive, simple };
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