1 // AST walker module for Mozilla Parser API compatible trees
6 // A simple walk is one where you simply specify callbacks to be
7 // called on specific nodes. The last two arguments are optional. A
10 // walk.simple(myTree, {
11 // Expression: function(node) { ... }
14 // to do something with all expressions. All Parser API node types
15 // can be used to identify node types, as well as Expression,
16 // Statement, and ScopeBody, which denote categories of nodes.
18 // The base argument can be used to pass a custom (recursive)
19 // walker, and state can be used to give this walked an initial
21 exports.simple = function(node, visitors, base, state) {
22 if (!base) base = exports;
23 function c(node, st, override) {
24 var type = override || node.type, found = visitors[type];
25 if (found) found(node, st);
26 base[type](node, st, c);
31 // A recursive walk is one where your functions override the default
32 // walkers. They can modify and replace the state parameter that's
33 // threaded through the walk, and can opt how and whether to walk
34 // their child nodes (by calling their third argument on these
36 exports.recursive = function(node, state, funcs, base) {
37 var visitor = exports.make(funcs, base);
38 function c(node, st, override) {
39 visitor[override || node.type](node, st, c);
44 // Used to create a custom walker. Will fill in all missing node
45 // type properties with the defaults.
46 exports.make = function(funcs, base) {
47 if (!base) base = exports;
49 for (var type in base)
50 visitor[type] = funcs.hasOwnProperty(type) ? funcs[type] : base[type];
54 function skipThrough(node, st, c) { c(node, st); }
55 function ignore(node, st, c) {}
59 exports.Program = exports.BlockStatement = function(node, st, c) {
60 for (var i = 0; i < node.body.length; ++i)
61 c(node.body[i], st, "Statement");
63 exports.Statement = skipThrough;
64 exports.EmptyStatement = ignore;
65 exports.ExpressionStatement = function(node, st, c) {
66 c(node.expression, st, "Expression");
68 exports.IfStatement = function(node, st, c) {
69 c(node.test, st, "Expression");
70 c(node.consequent, st, "Statement");
71 if (node.alternate) c(node.alternate, st, "Statement");
73 exports.LabeledStatement = function(node, st, c) {
74 c(node.body, st, "Statement");
76 exports.BreakStatement = exports.ContinueStatement = ignore;
77 exports.WithStatement = function(node, st, c) {
78 c(node.object, st, "Expression");
79 c(node.body, st, "Statement");
81 exports.SwitchStatement = function(node, st, c) {
82 c(node.discriminant, st, "Expression");
83 for (var i = 0; i < node.cases.length; ++i) {
84 var cs = node.cases[i];
85 if (cs.test) c(cs.test, st, "Expression");
86 for (var j = 0; j < cs.consequent.length; ++j)
87 c(cs.consequent[j], st, "Statement");
90 exports.ReturnStatement = function(node, st, c) {
91 if (node.argument) c(node.argument, st, "Expression");
93 exports.ThrowStatement = function(node, st, c) {
94 c(node.argument, st, "Expression");
96 exports.TryStatement = function(node, st, c) {
97 c(node.block, st, "Statement");
98 for (var i = 0; i < node.handlers.length; ++i)
99 c(node.handlers[i].body, st, "ScopeBody");
100 if (node.finalizer) c(node.finalizer, st, "Statement");
102 exports.WhileStatement = function(node, st, c) {
103 c(node.test, st, "Expression");
104 c(node.body, st, "Statement");
106 exports.DoWhileStatement = exports.WhileStatement;
107 exports.ForStatement = function(node, st, c) {
108 if (node.init) c(node.init, st, "ForInit");
109 if (node.test) c(node.test, st, "Expression");
110 if (node.update) c(node.update, st, "Expression");
111 c(node.body, st, "Statement");
113 exports.ForInStatement = function(node, st, c) {
114 c(node.left, st, "ForInit");
115 c(node.right, st, "Expression");
116 c(node.body, st, "Statement");
118 exports.ForInit = function(node, st, c) {
119 if (node.type == "VariableDeclaration") c(node, st);
120 else c(node, st, "Expression");
122 exports.DebuggerStatement = ignore;
124 exports.FunctionDeclaration = function(node, st, c) {
125 c(node, st, "Function");
127 exports.VariableDeclaration = function(node, st, c) {
128 for (var i = 0; i < node.declarations.length; ++i) {
129 var decl = node.declarations[i];
130 if (decl.init) c(decl.init, st, "Expression");
134 exports.Function = function(node, st, c) {
135 c(node.body, st, "ScopeBody");
137 exports.ScopeBody = function(node, st, c) {
138 c(node, st, "Statement");
141 exports.Expression = skipThrough;
142 exports.ThisExpression = ignore;
143 exports.ArrayExpression = function(node, st, c) {
144 for (var i = 0; i < node.elements.length; ++i) {
145 var elt = node.elements[i];
146 if (elt) c(elt, st, "Expression");
149 exports.ObjectExpression = function(node, st, c) {
150 for (var i = 0; i < node.properties.length; ++i)
151 c(node.properties[i].value, st, "Expression");
153 exports.FunctionExpression = exports.FunctionDeclaration;
154 exports.SequenceExpression = function(node, st, c) {
155 for (var i = 0; i < node.expressions.length; ++i)
156 c(node.expressions[i], st, "Expression");
158 exports.UnaryExpression = exports.UpdateExpression = function(node, st, c) {
159 c(node.argument, st, "Expression");
161 exports.BinaryExpression = exports.AssignmentExpression = exports.LogicalExpression = function(node, st, c) {
162 c(node.left, st, "Expression");
163 c(node.right, st, "Expression");
165 exports.ConditionalExpression = function(node, st, c) {
166 c(node.test, st, "Expression");
167 c(node.consequent, st, "Expression");
168 c(node.alternate, st, "Expression");
170 exports.NewExpression = exports.CallExpression = function(node, st, c) {
171 c(node.callee, st, "Expression");
172 if (node.arguments) for (var i = 0; i < node.arguments.length; ++i)
173 c(node.arguments[i], st, "Expression");
175 exports.MemberExpression = function(node, st, c) {
176 c(node.object, st, "Expression");
177 if (node.computed) c(node.property, st, "Expression");
179 exports.Identifier = exports.Literal = ignore;
181 // A custom walker that keeps track of the scope chain and the
182 // variables defined in it.
183 function makeScope(prev) {
184 return {vars: Object.create(null), prev: prev};
186 exports.scopeVisitor = exports.make({
187 Function: function(node, scope, c) {
188 var inner = makeScope(scope);
189 for (var i = 0; i < node.params.length; ++i)
190 inner.vars[node.params[i].name] = {type: "argument", node: node.params[i]};
192 var decl = node.type == "FunctionDeclaration";
193 (decl ? scope : inner).vars[node.id.name] =
194 {type: decl ? "function" : "function name", node: node.id};
196 c(node.body, inner, "ScopeBody");
198 TryStatement: function(node, scope, c) {
199 c(node.block, scope, "Statement");
200 for (var i = 0; i < node.handlers.length; ++i) {
201 var handler = node.handlers[i], inner = makeScope(scope);
202 inner.vars[handler.param.name] = {type: "catch clause", node: handler.param};
203 c(handler.body, inner, "ScopeBody");
205 if (node.finalizer) c(node.finalizer, scope, "Statement");
207 VariableDeclaration: function(node, scope, c) {
208 for (var i = 0; i < node.declarations.length; ++i) {
209 var decl = node.declarations[i];
210 scope.vars[decl.id.name] = {type: "var", node: decl.id};
211 if (decl.init) c(decl.init, scope, "Expression");
216 })(typeof exports == "undefined" ? acorn.walk = {} : exports);