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Support AssignmentPattern
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This is used for default values.
After that, we need to drop default parameter support.
CAUTION: There's no fully supported TDZ scope yet.
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@Constellation
Constellation committed Mar 11, 2015
1 parent dcb3231 commit b713c53
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Showing 2 changed files with 125 additions and 47 deletions.
96 changes: 49 additions & 47 deletions src/referencer.js
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Original file line number Diff line number Diff line change
Expand Up @@ -21,64 +21,69 @@
(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
import estraverse from 'estraverse';
import { Syntax } from 'estraverse';
import esrecurse from 'esrecurse';
import Reference from './reference';
import Variable from './variable';
import { ParameterDefinition, Definition } from './definition';
import assert from 'assert';

const Syntax = estraverse.Syntax;
class PatternVisitor extends esrecurse.Visitor {
constructor(rootPattern, referencer, callback) {
super(this);
this.referencer = referencer;
this.callback = callback;
}

function traverseIdentifierInPattern(rootPattern, callback) {
estraverse.traverse(rootPattern, {
enter(pattern, parent) {
var i, iz, element, property;
perform(pattern) {
if (pattern.type === Syntax.Identifier) {
this.callback(pattern, true);
return;
}
this.visit(pattern);
}

switch (pattern.type) {
case Syntax.Identifier:
// Toplevel identifier.
if (parent === null) {
callback(pattern, true);
}
break;
Identifier(pattern) {
this.callback(pattern, false);
}

case Syntax.SpreadElement:
if (pattern.argument.type === Syntax.Identifier) {
callback(pattern.argument, false);
}
break;

case Syntax.ObjectPattern:
for (i = 0, iz = pattern.properties.length; i < iz; ++i) {
property = pattern.properties[i];
if (property.shorthand) {
callback(property.key, false);
continue;
}
if (property.value.type === Syntax.Identifier) {
callback(property.value, false);
continue;
}
}
break;

case Syntax.ArrayPattern:
for (i = 0, iz = pattern.elements.length; i < iz; ++i) {
element = pattern.elements[i];
if (element && element.type === Syntax.Identifier) {
callback(element, false);
}
}
break;
ObjectPattern(pattern) {
var i, iz, property;
for (i = 0, iz = pattern.properties.length; i < iz; ++i) {
property = pattern.properties[i];
if (property.shorthand) {
this.visit(property.key);
continue;
}
this.visit(property.value);
}
}

ArrayPattern(pattern) {
var i, iz, element;
for (i = 0, iz = pattern.elements.length; i < iz; ++i) {
element = pattern.elements[i];
if (element) {
this.visit(element);
}
}
});
}

AssignmentPattern(pattern) {
this.visit(pattern.left);
// FIXME: Condier TDZ scope.
this.referencer.visit(pattern.right);
}
}

function traverseIdentifierInPattern(rootPattern, referencer, callback) {
var visitor = new PatternVisitor(rootPattern, referencer, callback);
visitor.perform(rootPattern);
}

function isPattern(node) {
var nodeType = node.type;
return nodeType === Syntax.Identifier || nodeType === Syntax.ObjectPattern || nodeType === Syntax.ArrayPattern || nodeType === Syntax.SpreadElement;
return nodeType === Syntax.Identifier || nodeType === Syntax.ObjectPattern || nodeType === Syntax.ArrayPattern || nodeType === Syntax.SpreadElement || nodeType === Syntax.RestElement || nodeType === Syntax.AssignmentPattern;
}

// Importing ImportDeclaration.
Expand Down Expand Up @@ -178,7 +183,7 @@ export default class Referencer extends esrecurse.Visitor {
}

visitPattern(node, callback) {
traverseIdentifierInPattern(node, callback);
traverseIdentifierInPattern(node, this, callback);
}

visitFunction(node) {
Expand Down Expand Up @@ -332,9 +337,6 @@ export default class Referencer extends esrecurse.Visitor {

decl = node.declarations[index];
init = decl.init;
// FIXME: Don't consider initializer with complex patterns.
// Such as,
// var [a, b, c = 20] = array;
this.visitPattern(decl.id, (pattern, toplevel) => {
variableTargetScope.__define(pattern,
new Definition(
Expand Down
76 changes: 76 additions & 0 deletions test/es6-destructuring-assignments.coffee
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Expand Up @@ -23,6 +23,7 @@

expect = require('chai').expect
harmony = require '../third_party/esprima'
espree = require '../third_party/espree'
escope = require '..'

describe 'ES6 destructuring assignments', ->
Expand Down Expand Up @@ -703,4 +704,79 @@ describe 'ES6 destructuring assignments', ->
expect(scope.variables[index].name).to.be.equal name
expect(scope.references).to.have.length 0

it 'default values and patterns in var', ->
ast = espree """
(function () {
var [a, b, c, d = 20 ] = array;
}());
"""

scopeManager = escope.analyze ast, ecmaVersion: 6
expect(scopeManager.scopes).to.have.length 2

scope = scopeManager.scopes[0]
globalScope = scope
expect(scope.type).to.be.equal 'global'
expect(scope.variables).to.have.length 0
expect(scope.references).to.have.length 0

scope = scopeManager.scopes[1]
expect(scope.type).to.be.equal 'function'
expect(scope.variables).to.have.length 5
for name, index in [
'arguments'
'a'
'b'
'c'
'd'
]
expect(scope.variables[index].name).to.be.equal name
expect(scope.references).to.have.length 5
for name, index in [
'a'
'b'
'c'
'd'
'array'
]
expect(scope.references[index].identifier.name).to.be.equal name

it 'default values containing references and patterns in var', ->
ast = espree """
(function () {
var [a, b, c, d = e ] = array;
}());
"""

scopeManager = escope.analyze ast, ecmaVersion: 6
expect(scopeManager.scopes).to.have.length 2

scope = scopeManager.scopes[0]
globalScope = scope
expect(scope.type).to.be.equal 'global'
expect(scope.variables).to.have.length 0
expect(scope.references).to.have.length 0

scope = scopeManager.scopes[1]
expect(scope.type).to.be.equal 'function'
expect(scope.variables).to.have.length 5
for name, index in [
'arguments'
'a'
'b'
'c'
'd'
]
expect(scope.variables[index].name).to.be.equal name
expect(scope.references).to.have.length 6
for name, index in [
'a'
'b'
'c'
'd'
'e'
'array'
]
expect(scope.references[index].identifier.name).to.be.equal name

# vim: set sw=4 ts=4 et tw=80 :

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