Add an AST walker utility

This commit is contained in:
Marijn Haverbeke 2012-11-05 22:32:39 +01:00
parent 16f8259dab
commit b660ff6d1c

183
util/walk.js Normal file
View File

@ -0,0 +1,183 @@
(function(exports) {
"use strict";
exports.simple = function(node, visitors, base, state) {
if (!base) base = exports;
function c(node, st, override) {
var type = override || node.type, found = visitors[type];
if (found) found(node, st);
base[type](node, st, c);
}
c(node, state);
};
exports.recursive = function(node, state, funcs, base) {
var visitor = exports.make(funcs, base);
function c(node, st, override) {
visitor[override || node.type](node, st, c);
}
c(node, state);
};
exports.make = function(funcs, base) {
if (!base) base = exports;
var visitor = {};
for (var type in base)
visitor[type] = funcs.hasOwnProperty(type) ? funcs[type] : base[type];
return visitor;
};
function skipThrough(node, st, c) { c(node, st); }
function ignore(node, st, c) {}
exports.Program = exports.BlockStatement = function(node, st, c) {
for (var i = 0; i < node.body.length; ++i)
c(node.body[i], st, "Statement");
};
exports.Statement = skipThrough;
exports.EmptyStatement = ignore;
exports.ExpressionStatement = function(node, st, c) {
c(node.expression, st, "Expression");
};
exports.IfStatement = function(node, st, c) {
c(node.test, st, "Expression");
c(node.consequent, st, "Statement");
if (node.alternate) c(node.alternate, st, "Statement");
};
exports.LabeledStatement = function(node, st, c) {
c(node.body, st, "Statement");
};
exports.BreakStatement = exports.ContinueStatement = ignore;
exports.WithStatement = function(node, st, c) {
c(node.object, st, "Expression");
c(node.body, st, "Statement");
};
exports.SwitchStatement = function(node, st, c) {
c(node.discriminant, st, "Expression");
for (var i = 0; i < node.cases.length; ++i) {
var cs = node.cases[i];
if (cs.test) c(cs.test, st, "Expression");
for (var j = 0; j < cs.consequent.length; ++j)
c(cs.consequent[j], st, "Statement");
}
};
exports.ReturnStatement = function(node, st, c) {
if (node.argument) c(node.argument, st, "Expression");
};
exports.ThrowStatement = function(node, st, c) {
c(node.argument, st, "Expression");
};
exports.TryStatement = function(node, st, c) {
c(node.block, st, "Statement");
for (var i = 0; i < node.handlers.length; ++i)
c(node.handlers[i].body, st, "ScopeBody");
if (node.finalizer) c(node.finalizer, st, "Statement");
};
exports.WhileStatement = function(node, st, c) {
c(node.test, st, "Expression");
c(node.body, st, "Statement");
};
exports.DoWhileStatement = exports.WhileStatement;
exports.ForStatement = function(node, st, c) {
if (node.init) c(node.init, st, "ForInit");
if (node.test) c(node.test, st, "Expression");
if (node.update) c(node.update, st, "Expression");
c(node.body, st, "Statement");
};
exports.ForInStatement = function(node, st, c) {
c(node.left, st, "ForInit");
c(node.right, st, "Expression");
c(node.body, st, "Statement");
};
exports.ForInit = function(node, st, c) {
if (node.type == "VariableDeclaration") c(node, st);
else c(node, st, "Expression");
};
exports.DebuggerStatement = ignore;
exports.FunctionDeclaration = function(node, st, c) {
c(node, st, "Function");
};
exports.VariableDeclaration = function(node, st, c) {
for (var i = 0; i < node.declarations.length; ++i) {
var decl = node.declarations[i];
if (decl.init) c(decl.init, st, "Expression");
}
};
exports.Function = function(node, st, c) {
c(node.body, st, "ScopeBody");
};
exports.ScopeBody = skipThrough;
exports.Expression = skipThrough;
exports.ThisExpression = ignore;
exports.ArrayExpression = function(node, st, c) {
for (var i = 0; i < node.elements.length; ++i) {
var elt = node.elements[i];
if (elt) c(elt, st, "Expression");
}
};
exports.ObjectExpression = function(node, st, c) {
for (var i = 0; i < node.properties.length; ++i)
c(node.properties[i].value, st, "Expression");
};
exports.FunctionExpression = exports.FunctionDeclaration;
exports.SequenceExpression = function(node, st, c) {
for (var i = 0; i < node.expressions.length; ++i)
c(node.expressions[i], st, "Expression");
};
exports.UnaryExpression = exports.UpdateExpression = function(node, st, c) {
c(node.argument, st, "Expression");
};
exports.BinaryExpression = exports.AssignmentExpression = exports.LogicalExpression = function(node, st, c) {
c(node.left, st, "Expression");
c(node.right, st, "Expression");
};
exports.ConditionalExpression = function(node, st, c) {
c(node.test, st, "Expression");
c(node.consequent, st, "Expression");
c(node.alternate, st, "Expression");
};
exports.NewExpression = exports.CallExpression = function(node, st, c) {
c(node.callee, st, "Expression");
if (node.arguments) for (var i = 0; i < node.arguments.length; ++i)
c(node.arguments[i], st, "Expression");
};
exports.MemberExpression = function(node, st, c) {
c(node.object, st, "Expression");
if (node.computed) c(node.property, st, "Expression");
};
exports.Identifier = exports.Literal = ignore;
function makeScope(prev) {
return {vars: Object.create(null), prev: prev};
}
exports.scopeVisitor = exports.make({
Function: function(node, scope, c) {
var inner = makeScope(scope);
for (var i = 0; i < node.params.length; ++i)
inner.vars[node.params[i].name] = "argument";
if (node.type == "FunctionDeclaration")
scope.vars[node.id.name] = "function";
else if (node.id)
inner.vars[node.id.name] = "function'";
c(node.body, inner, "ScopeBody");
},
TryStatement: function(node, scope, c) {
c(node.block, scope, "Statement");
for (var i = 0; i < node.handlers.length; ++i) {
var handler = node.handlers[i], inner = makeScope(scope);
inner.vars[handler.param.name] = "catch";
c(handler.body, inner, "ScopeBody");
}
if (node.finalizer) c(node.finalizer, scope, "Statement");
},
VariableDeclaration: function(node, scope, c) {
for (var i = 0; i < node.declarations.length; ++i) {
var decl = node.declarations[i];
scope.vars[decl.id.name] = "var";
if (decl.init) c(decl.init, scope, "Expression");
}
}
});
})(typeof exports == "undefined" ? acorn.walk = {} : exports);