Implement prefixed-destructuring assignment
https://bugs.webkit.org/show_bug.cgi?id=121930
Reviewed by Mark Hahnenberg.
Source/JavaScriptCore:
Relanding with fix after rollout - it helps to not completely destroy
optimisations for no reason.
LayoutTests:
Relanding with fix after rollout - it helps to not completely destroy
optimisations for no reason.
git-svn-id: http://svn.webkit.org/repository/webkit/trunk@156785 268f45cc-cd09-0410-ab3c-d52691b4dbfc
diff --git a/LayoutTests/js/destructuring-assignment-expected.txt b/LayoutTests/js/destructuring-assignment-expected.txt
new file mode 100644
index 0000000..c73ad63
--- /dev/null
+++ b/LayoutTests/js/destructuring-assignment-expected.txt
@@ -0,0 +1,69 @@
+basic tests for destructuring assignment
+
+On success, you will see a series of "PASS" messages, followed by "TEST COMPLETE".
+
+
+PASS var [a,b]=['1','2']; var r=a+b; r is '12'
+Function as String: (function([a,b]) { return a+b;})
+PASS (function([a,b]) { return a+b;})(['1','2']) is '12'
+PASS (function ([a,b]) { return a+b;})(['1','2']) is '12'
+PASS var {a,b}={a:'1',b:'2'}; var r=a+b; r is '12'
+Function as String: (function({a,b}) { return a+b;})
+PASS (function({a,b}) { return a+b;})({a:'1',b:'2'}) is '12'
+PASS (function ({a:a,b:b}) { return a+b;})({a:'1',b:'2'}) is '12'
+PASS var {c:a,d:b}={c:'1',d:'2'}; var r=a+b; r is '12'
+Function as String: (function({c:a,d:b}) { return a+b;})
+PASS (function({c:a,d:b}) { return a+b;})({c:'1',d:'2'}) is '12'
+PASS (function ({c:a,d:b}) { return a+b;})({c:'1',d:'2'}) is '12'
+PASS var {c:b,d:a}={c:'1',d:'2'}; var r=a+b; r is '21'
+Function as String: (function({c:b,d:a}) { return a+b;})
+PASS (function({c:b,d:a}) { return a+b;})({c:'1',d:'2'}) is '21'
+PASS (function ({c:b,d:a}) { return a+b;})({c:'1',d:'2'}) is '21'
+PASS var {true:a,false:b,undefined:c,null:d,in:e,for:f,1.5:g,'foo bar':h}={true:'a',false:'b',undefined:'c',null:'d',in:'e',for:'f',1.5:'g','foo bar':'h'}; var r=a+b+c+d+e+f+g+h; r is 'abcdefgh'
+Function as String: (function({true:a,false:b,undefined:c,null:d,in:e,for:f,1.5:g,'foo bar':h}) { return a+b+c+d+e+f+g+h;})
+PASS (function({true:a,false:b,undefined:c,null:d,in:e,for:f,1.5:g,'foo bar':h}) { return a+b+c+d+e+f+g+h;})({true:'a',false:'b',undefined:'c',null:'d',in:'e',for:'f',1.5:'g','foo bar':'h'}) is 'abcdefgh'
+PASS (function ({true:a,false:b,undefined:c,null:d,in:e,for:f,1.5:g,"foo bar":h}) { return a+b+c+d+e+f+g+h;})({true:'a',false:'b',undefined:'c',null:'d',in:'e',for:'f',1.5:'g','foo bar':'h'}) is 'abcdefgh'
+PASS var [{c:a,d:b}]=[{c:'1',d:'2'}]; var r=a+b; r is '12'
+Function as String: (function([{c:a,d:b}]) { return a+b;})
+PASS (function([{c:a,d:b}]) { return a+b;})([{c:'1',d:'2'}]) is '12'
+PASS (function ([{c:a,d:b}]) { return a+b;})([{c:'1',d:'2'}]) is '12'
+PASS var {x:[{c:a,d:b}]}={x:[{c:'1',d:'2'}]}; var r=a+b; r is '12'
+Function as String: (function({x:[{c:a,d:b}]}) { return a+b;})
+PASS (function({x:[{c:a,d:b}]}) { return a+b;})({x:[{c:'1',d:'2'}]}) is '12'
+PASS (function ({x:[{c:a,d:b}]}) { return a+b;})({x:[{c:'1',d:'2'}]}) is '12'
+PASS var [a,b]=anArray; var r=a+b; r is '12'
+Function as String: (function([a,b]) { return a+b;})
+PASS (function([a,b]) { return a+b;})(anArray) is '12'
+PASS (function ([a,b]) { return a+b;})(anArray) is '12'
+PASS var {a,b}=anArray; var r=a+b; r is '34'
+Function as String: (function({a,b}) { return a+b;})
+PASS (function({a,b}) { return a+b;})(anArray) is '34'
+PASS (function ({a:a,b:b}) { return a+b;})(anArray) is '34'
+PASS var {a:a,b:b}=anArray; var r=a+b; r is '34'
+Function as String: (function({a:a,b:b}) { return a+b;})
+PASS (function({a:a,b:b}) { return a+b;})(anArray) is '34'
+PASS (function ({a:a,b:b}) { return a+b;})(anArray) is '34'
+PASS var {a,b}=anObject; var r=a+b; r is '12'
+Function as String: (function({a,b}) { return a+b;})
+PASS (function({a,b}) { return a+b;})(anObject) is '12'
+PASS (function ({a:a,b:b}) { return a+b;})(anObject) is '12'
+PASS var {a:a,b:b}=anObject; var r=a+b; r is '12'
+Function as String: (function({a:a,b:b}) { return a+b;})
+PASS (function({a:a,b:b}) { return a+b;})(anObject) is '12'
+PASS (function ({a:a,b:b}) { return a+b;})(anObject) is '12'
+PASS var {0:a,1:b}=anObject; var r=a+b; r is '34'
+Function as String: (function({0:a,1:b}) { return a+b;})
+PASS (function({0:a,1:b}) { return a+b;})(anObject) is '34'
+PASS (function ({0:a,1:b}) { return a+b;})(anObject) is '34'
+PASS var {'a':a,'b':b}=anObject; var r=a+b; r is '12'
+Function as String: (function({'a':a,'b':b}) { return a+b;})
+PASS (function({'a':a,'b':b}) { return a+b;})(anObject) is '12'
+PASS (function ({"a":a,"b":b}) { return a+b;})(anObject) is '12'
+PASS a+b is '1122'
+PASS a+b is '2211'
+PASS testDeconstructArgs('1', '2') is '12'
+PASS testDeconstructArgLength('1', '2') is 2
+PASS successfullyParsed is true
+
+TEST COMPLETE
+
diff --git a/LayoutTests/js/destructuring-assignment.html b/LayoutTests/js/destructuring-assignment.html
new file mode 100644
index 0000000..a5ffe5b
--- /dev/null
+++ b/LayoutTests/js/destructuring-assignment.html
@@ -0,0 +1,10 @@
+<!DOCTYPE HTML PUBLIC "-//IETF//DTD HTML//EN">
+<html>
+<head>
+<script src="../resources/js-test-pre.js"></script>
+</head>
+<body>
+<script src="script-tests/destructuring-assignment.js"></script>
+<script src="../resources/js-test-post.js"></script>
+</body>
+</html>
diff --git a/LayoutTests/js/mozilla/strict/13.1-expected.txt b/LayoutTests/js/mozilla/strict/13.1-expected.txt
index c236524..817775136 100644
--- a/LayoutTests/js/mozilla/strict/13.1-expected.txt
+++ b/LayoutTests/js/mozilla/strict/13.1-expected.txt
@@ -10,8 +10,8 @@
PASS Function("'use strict'; function f(a,b,c,d,e,f,g,h,d) {}") threw exception of type SyntaxError.
PASS !!Function("function f(a,b,c,d,e,f,g,h,d) {}") is true
PASS true === true
-PASS Function("'use strict'; function f([x,y]) {}") threw exception of type SyntaxError.
-PASS Function("function f([x,y]) {}") threw exception of type SyntaxError.
+PASS !!Function("'use strict'; function f([x,y]) {}") is true
+PASS !!Function("function f([x,y]) {}") is true
PASS true === true
PASS Function("'use strict'; function f([x,x]){}") threw exception of type SyntaxError.
PASS Function("function f([x,x]){}") threw exception of type SyntaxError.
@@ -38,10 +38,10 @@
PASS !!Function("function f(eval){}") is true
PASS true === true
PASS Function("'use strict'; function f([eval]){}") threw exception of type SyntaxError.
-PASS Function("function f([eval]){}") threw exception of type SyntaxError.
+PASS !!Function("function f([eval]){}") is true
PASS true === true
PASS Function("'use strict'; function f({x:eval}){}") threw exception of type SyntaxError.
-PASS Function("function f({x:eval}){}") threw exception of type SyntaxError.
+PASS !!Function("function f({x:eval}){}") is true
PASS true === true
PASS Function("'use strict'; function eval(){}") threw exception of type SyntaxError.
PASS !!Function("function eval(){}") is true
@@ -62,10 +62,10 @@
PASS !!Function("(function f(eval){})") is true
PASS true === true
PASS Function("'use strict'; (function f([eval]){})") threw exception of type SyntaxError.
-PASS Function("(function f([eval]){})") threw exception of type SyntaxError.
+PASS !!Function("(function f([eval]){})") is true
PASS true === true
PASS Function("'use strict'; (function f({x:eval}){})") threw exception of type SyntaxError.
-PASS Function("(function f({x:eval}){})") threw exception of type SyntaxError.
+PASS !!Function("(function f({x:eval}){})") is true
PASS true === true
PASS Function("'use strict'; (function eval(){})") threw exception of type SyntaxError.
PASS !!Function("(function eval(){})") is true
@@ -98,10 +98,10 @@
PASS !!Function("({set x(eval){}})") is true
PASS true === true
PASS Function("'use strict'; ({set x([eval]){}})") threw exception of type SyntaxError.
-PASS Function("({set x([eval]){}})") threw exception of type SyntaxError.
+PASS !!Function("({set x([eval]){}})") is true
PASS true === true
PASS Function("'use strict'; ({set x({x:eval}){}})") threw exception of type SyntaxError.
-PASS Function("({set x({x:eval}){}})") threw exception of type SyntaxError.
+PASS !!Function("({set x({x:eval}){}})") is true
PASS true === true
PASS Function("'use strict'; ({set x(eval){\"use strict\";}})") threw exception of type SyntaxError.
PASS Function("({set x(eval){\"use strict\";}})") threw exception of type SyntaxError.
@@ -116,10 +116,10 @@
PASS !!Function("function f(arguments){}") is true
PASS true === true
PASS Function("'use strict'; function f([arguments]){}") threw exception of type SyntaxError.
-PASS Function("function f([arguments]){}") threw exception of type SyntaxError.
+PASS !!Function("function f([arguments]){}") is true
PASS true === true
PASS Function("'use strict'; function f({x:arguments}){}") threw exception of type SyntaxError.
-PASS Function("function f({x:arguments}){}") threw exception of type SyntaxError.
+PASS !!Function("function f({x:arguments}){}") is true
PASS true === true
PASS Function("'use strict'; function arguments(){}") threw exception of type SyntaxError.
PASS !!Function("function arguments(){}") is true
@@ -140,10 +140,10 @@
PASS !!Function("(function f(arguments){})") is true
PASS true === true
PASS Function("'use strict'; (function f([arguments]){})") threw exception of type SyntaxError.
-PASS Function("(function f([arguments]){})") threw exception of type SyntaxError.
+PASS !!Function("(function f([arguments]){})") is true
PASS true === true
PASS Function("'use strict'; (function f({x:arguments}){})") threw exception of type SyntaxError.
-PASS Function("(function f({x:arguments}){})") threw exception of type SyntaxError.
+PASS !!Function("(function f({x:arguments}){})") is true
PASS true === true
PASS Function("'use strict'; (function arguments(){})") threw exception of type SyntaxError.
PASS !!Function("(function arguments(){})") is true
@@ -176,10 +176,10 @@
PASS !!Function("({set x(arguments){}})") is true
PASS true === true
PASS Function("'use strict'; ({set x([arguments]){}})") threw exception of type SyntaxError.
-PASS Function("({set x([arguments]){}})") threw exception of type SyntaxError.
+PASS !!Function("({set x([arguments]){}})") is true
PASS true === true
PASS Function("'use strict'; ({set x({x:arguments}){}})") threw exception of type SyntaxError.
-PASS Function("({set x({x:arguments}){}})") threw exception of type SyntaxError.
+PASS !!Function("({set x({x:arguments}){}})") is true
PASS true === true
PASS Function("'use strict'; ({set x(arguments){\"use strict\";}})") threw exception of type SyntaxError.
PASS Function("({set x(arguments){\"use strict\";}})") threw exception of type SyntaxError.
diff --git a/LayoutTests/js/mozilla/strict/regress-532254-expected.txt b/LayoutTests/js/mozilla/strict/regress-532254-expected.txt
index 8d40268..184e589 100644
--- a/LayoutTests/js/mozilla/strict/regress-532254-expected.txt
+++ b/LayoutTests/js/mozilla/strict/regress-532254-expected.txt
@@ -1,5 +1,5 @@
PASS Function("'use strict'; function f(eval,[x]){}") threw exception of type SyntaxError.
-FAIL !!Function("function f(eval,[x]){}") should be true. Threw exception SyntaxError: Expected an identifier but found '[' instead
+PASS !!Function("function f(eval,[x]){}") is true
PASS true === true
PASSED!
PASS successfullyParsed is true
diff --git a/LayoutTests/js/mozilla/strict/script-tests/13.1.js b/LayoutTests/js/mozilla/strict/script-tests/13.1.js
index e7e1b09..c1c5e6e 100644
--- a/LayoutTests/js/mozilla/strict/script-tests/13.1.js
+++ b/LayoutTests/js/mozilla/strict/script-tests/13.1.js
@@ -39,8 +39,8 @@
*/
// Destructuring is not valid ES5 syntax.
assertEq(testLenientAndStrict('function f([x,y]) {}',
- parseRaisesException(SyntaxError),
- parseRaisesException(SyntaxError)),
+ parsesSuccessfully,
+ parsesSuccessfully),
true);
assertEq(testLenientAndStrict('function f([x,x]){}',
parseRaisesException(SyntaxError),
@@ -118,12 +118,12 @@
true);
// Destructuring is not valid ES5 syntax.
assertEq(testLenientAndStrict('function f([eval]){}',
- parseRaisesException(SyntaxError),
+ parsesSuccessfully,
parseRaisesException(SyntaxError)),
true);
// Destructuring is not valid ES5 syntax.
assertEq(testLenientAndStrict('function f({x:eval}){}',
- parseRaisesException(SyntaxError),
+ parsesSuccessfully,
parseRaisesException(SyntaxError)),
true);
assertEq(testLenientAndStrict('function eval(){}',
@@ -154,12 +154,12 @@
true);
// Destructuring is not valid ES5 syntax.
assertEq(testLenientAndStrict('(function f([eval]){})',
- parseRaisesException(SyntaxError),
+ parsesSuccessfully,
parseRaisesException(SyntaxError)),
true);
// Destructuring is not valid ES5 syntax.
assertEq(testLenientAndStrict('(function f({x:eval}){})',
- parseRaisesException(SyntaxError),
+ parsesSuccessfully,
parseRaisesException(SyntaxError)),
true);
assertEq(testLenientAndStrict('(function eval(){})',
@@ -208,12 +208,12 @@
true);
// Destructuring is not valid ES5 syntax.
assertEq(testLenientAndStrict('({set x([eval]){}})',
- parseRaisesException(SyntaxError),
+ parsesSuccessfully,
parseRaisesException(SyntaxError)),
true);
// Destructuring is not valid ES5 syntax.
assertEq(testLenientAndStrict('({set x({x:eval}){}})',
- parseRaisesException(SyntaxError),
+ parsesSuccessfully,
parseRaisesException(SyntaxError)),
true);
assertEq(testLenientAndStrict('({set x(eval){"use strict";}})',
@@ -234,12 +234,12 @@
true);
// Destructuring is not valid ES5 syntax.
assertEq(testLenientAndStrict('function f([arguments]){}',
- parseRaisesException(SyntaxError),
+ parsesSuccessfully,
parseRaisesException(SyntaxError)),
true);
// Destructuring is not valid ES5 syntax.
assertEq(testLenientAndStrict('function f({x:arguments}){}',
- parseRaisesException(SyntaxError),
+ parsesSuccessfully,
parseRaisesException(SyntaxError)),
true);
assertEq(testLenientAndStrict('function arguments(){}',
@@ -269,12 +269,12 @@
true);
// Destructuring is not valid ES5 syntax.
assertEq(testLenientAndStrict('(function f([arguments]){})',
- parseRaisesException(SyntaxError),
+ parsesSuccessfully,
parseRaisesException(SyntaxError)),
true);
// Destructuring is not valid ES5 syntax.
assertEq(testLenientAndStrict('(function f({x:arguments}){})',
- parseRaisesException(SyntaxError),
+ parsesSuccessfully,
parseRaisesException(SyntaxError)),
true);
assertEq(testLenientAndStrict('(function arguments(){})',
@@ -323,12 +323,12 @@
true);
// Destructuring is not valid ES5 syntax.
assertEq(testLenientAndStrict('({set x([arguments]){}})',
- parseRaisesException(SyntaxError),
+ parsesSuccessfully,
parseRaisesException(SyntaxError)),
true);
// Destructuring is not valid ES5 syntax.
assertEq(testLenientAndStrict('({set x({x:arguments}){}})',
- parseRaisesException(SyntaxError),
+ parsesSuccessfully,
parseRaisesException(SyntaxError)),
true);
assertEq(testLenientAndStrict('({set x(arguments){"use strict";}})',
diff --git a/LayoutTests/js/regress/destructuring-arguments-expected.txt b/LayoutTests/js/regress/destructuring-arguments-expected.txt
new file mode 100644
index 0000000..308229bf
--- /dev/null
+++ b/LayoutTests/js/regress/destructuring-arguments-expected.txt
@@ -0,0 +1,10 @@
+JSRegress/destructuring-arguments
+
+On success, you will see a series of "PASS" messages, followed by "TEST COMPLETE".
+
+
+PASS no exception thrown
+PASS successfullyParsed is true
+
+TEST COMPLETE
+
diff --git a/LayoutTests/js/regress/destructuring-arguments-length-expected.txt b/LayoutTests/js/regress/destructuring-arguments-length-expected.txt
new file mode 100644
index 0000000..4138f83
--- /dev/null
+++ b/LayoutTests/js/regress/destructuring-arguments-length-expected.txt
@@ -0,0 +1,10 @@
+JSRegress/destructuring-arguments-length
+
+On success, you will see a series of "PASS" messages, followed by "TEST COMPLETE".
+
+
+PASS no exception thrown
+PASS successfullyParsed is true
+
+TEST COMPLETE
+
diff --git a/LayoutTests/js/regress/destructuring-arguments-length.html b/LayoutTests/js/regress/destructuring-arguments-length.html
new file mode 100644
index 0000000..7419ce8
--- /dev/null
+++ b/LayoutTests/js/regress/destructuring-arguments-length.html
@@ -0,0 +1,12 @@
+<!DOCTYPE HTML PUBLIC "-//IETF//DTD HTML//EN">
+<html>
+<head>
+<script src="../../resources/js-test-pre.js"></script>
+</head>
+<body>
+<script src="resources/regress-pre.js"></script>
+<script src="script-tests/destructuring-arguments-length.js"></script>
+<script src="resources/regress-post.js"></script>
+<script src="../../resources/js-test-post.js"></script>
+</body>
+</html>
diff --git a/LayoutTests/js/regress/destructuring-arguments.html b/LayoutTests/js/regress/destructuring-arguments.html
new file mode 100644
index 0000000..7fda8d8
--- /dev/null
+++ b/LayoutTests/js/regress/destructuring-arguments.html
@@ -0,0 +1,12 @@
+<!DOCTYPE HTML PUBLIC "-//IETF//DTD HTML//EN">
+<html>
+<head>
+<script src="../../resources/js-test-pre.js"></script>
+</head>
+<body>
+<script src="resources/regress-pre.js"></script>
+<script src="script-tests/destructuring-arguments.js"></script>
+<script src="resources/regress-post.js"></script>
+<script src="../../resources/js-test-post.js"></script>
+</body>
+</html>
diff --git a/LayoutTests/js/regress/destructuring-swap-expected.txt b/LayoutTests/js/regress/destructuring-swap-expected.txt
new file mode 100644
index 0000000..513f630
--- /dev/null
+++ b/LayoutTests/js/regress/destructuring-swap-expected.txt
@@ -0,0 +1,10 @@
+JSRegress/destructuring-swap
+
+On success, you will see a series of "PASS" messages, followed by "TEST COMPLETE".
+
+
+PASS no exception thrown
+PASS successfullyParsed is true
+
+TEST COMPLETE
+
diff --git a/LayoutTests/js/regress/destructuring-swap.html b/LayoutTests/js/regress/destructuring-swap.html
new file mode 100644
index 0000000..1505860
--- /dev/null
+++ b/LayoutTests/js/regress/destructuring-swap.html
@@ -0,0 +1,12 @@
+<!DOCTYPE HTML PUBLIC "-//IETF//DTD HTML//EN">
+<html>
+<head>
+<script src="../../resources/js-test-pre.js"></script>
+</head>
+<body>
+<script src="resources/regress-pre.js"></script>
+<script src="script-tests/destructuring-swap.js"></script>
+<script src="resources/regress-post.js"></script>
+<script src="../../resources/js-test-post.js"></script>
+</body>
+</html>
diff --git a/LayoutTests/js/regress/script-tests/destructuring-arguments-length.js b/LayoutTests/js/regress/script-tests/destructuring-arguments-length.js
new file mode 100644
index 0000000..967e340
--- /dev/null
+++ b/LayoutTests/js/regress/script-tests/destructuring-arguments-length.js
@@ -0,0 +1,13 @@
+//@ runDefault
+
+function foo() {
+ var {0: i, 1: j, length} = arguments;
+ return i + j + length;
+}
+
+var result = 0;
+for (var i = 0; i < 1000000; ++i)
+ result += foo(i, 1);
+
+if (result != 500002500000)
+ throw "Bad result: " + result;
diff --git a/LayoutTests/js/regress/script-tests/destructuring-arguments.js b/LayoutTests/js/regress/script-tests/destructuring-arguments.js
new file mode 100644
index 0000000..5c6dbee
--- /dev/null
+++ b/LayoutTests/js/regress/script-tests/destructuring-arguments.js
@@ -0,0 +1,13 @@
+//@ runDefault
+
+function foo() {
+ var [a, b] = arguments;
+ return a - b;
+}
+
+var result = 0;
+for (var i = 0; i < 1000000; ++i)
+ result += foo(42, i);
+
+if (result != -499957500000)
+ throw "Bad result: " + result;
diff --git a/LayoutTests/js/regress/script-tests/destructuring-swap.js b/LayoutTests/js/regress/script-tests/destructuring-swap.js
new file mode 100644
index 0000000..6f764c1
--- /dev/null
+++ b/LayoutTests/js/regress/script-tests/destructuring-swap.js
@@ -0,0 +1,13 @@
+//@ runDefault
+
+function foo(a, b) {
+ var [a, b] = [b, a];
+ return a - b;
+}
+
+var result = 0;
+for (var i = 0; i < 1000000; ++i)
+ result += foo(42, i);
+
+if (result != 499957500000)
+ throw "Bad result: " + result;
diff --git a/LayoutTests/js/script-tests/destructuring-assignment.js b/LayoutTests/js/script-tests/destructuring-assignment.js
new file mode 100644
index 0000000..9a860ef
--- /dev/null
+++ b/LayoutTests/js/script-tests/destructuring-assignment.js
@@ -0,0 +1,48 @@
+description("basic tests for destructuring assignment");
+
+function testDestructuring(pattern, expression, result, expr) {
+ if (!expr) expr = "a+b"
+ shouldBe("var " + pattern + "=" + expression + "; var r="+expr+"; r", result);
+ var functionString = "(function(" + pattern + ") { return "+expr+";})";
+ debug("Function as String: " + functionString);
+ shouldBe(functionString + "(" + expression + ")", result);
+ shouldBe("(" + eval(functionString) + ")(" + expression + ")", result);
+}
+
+testDestructuring("[a,b]", "['1','2']", "'12'");
+testDestructuring("{a,b}", "{a:'1',b:'2'}", "'12'");
+testDestructuring("{c:a,d:b}", "{c:'1',d:'2'}", "'12'");
+testDestructuring("{c:b,d:a}", "{c:'1',d:'2'}", "'21'");
+testDestructuring("{true:a,false:b,undefined:c,null:d,in:e,for:f,1.5:g,'foo bar':h}", "{true:'a',false:'b',undefined:'c',null:'d',in:'e',for:'f',1.5:'g','foo bar':'h'}", "'abcdefgh'", "a+b+c+d+e+f+g+h");
+testDestructuring("[{c:a,d:b}]", "[{c:'1',d:'2'}]", "'12'");
+testDestructuring("{x:[{c:a,d:b}]}", "{x:[{c:'1',d:'2'}]}", "'12'");
+
+var anArray = ['1', '2'];
+anArray.a = '3'
+anArray.b = '4'
+var anObject = {a:'1', b:'2', 0:'3',1:'4'}
+testDestructuring("[a,b]", "anArray", "'12'");
+testDestructuring("{a,b}", "anArray", "'34'");
+testDestructuring("{a:a,b:b}", "anArray", "'34'");
+testDestructuring("{a,b}", "anObject", "'12'");
+testDestructuring("{a:a,b:b}", "anObject", "'12'");
+testDestructuring("{0:a,1:b}", "anObject", "'34'");
+testDestructuring("{'a':a,'b':b}", "anObject", "'12'");
+var [a,b] = ['11','22']
+shouldBe("a+b", "'1122'")
+var [b,a] = [a,b];
+shouldBe("a+b", "'2211'")
+function testDeconstructArgs() {
+ var [a,b] = arguments;
+ return a+b;
+}
+
+function testDeconstructArgLength() {
+ var {length} = arguments;
+ return length;
+}
+shouldBe("testDeconstructArgs('1', '2')", "'12'");
+shouldBe("testDeconstructArgLength('1', '2')", "2");
+
+
+
