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comparison core-javascript/core-javascript-work/tutorial.js @ 135:f9f6684f9b32 core-javascript

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$ hg mv tutorial.js core-javascript-work/ # and amend the rst files also
author jf3243
date Mon, 31 Oct 2011 11:07:46 +0000
parents core-javascript/tutorial.js@31a94b4c8687
children 20d76c716c9d
comparison
equal deleted inserted replaced
134:31a94b4c8687 135:f9f6684f9b32
1 var telltail = 'global';
2
3 var TEST = function(title, code){
4 print( 'Testing: ' + title );
5 code();
6 };
7
8 var assert = function(arg){
9 if(!arg){
10 ddt();
11 }
12 };
13
14 '0' == 0 || ddt;
15 0 == '' || ddt;
16 '0' != '' || ddt;
17 NaN != NaN || ddt;
18
19
20 // start closures
21 TEST('closures', function()
22 {
23 // A factory for creating get-set pairs.
24 var get_set_factory = function(){
25
26 var value;
27 var get = function(){
28 return value;
29 };
30 var set = function(new_value){
31 value = new_value;
32 };
33
34 return {
35 get: get,
36 set: set
37 };
38 };
39
40 // Create and unpack two get-set pairs.
41 var tmp;
42 tmp= get_set_factory();
43 var get_a = tmp.get;
44 var set_a = tmp.set;
45
46 tmp= get_set_factory();
47 var get_b = tmp.get;
48 var set_b = tmp.set;
49
50 // Test that both pairs work.
51 set_a(12);
52 assert( get_a() === 12 );
53
54 set_b(13);
55 assert( get_b() === 13 );
56
57 // Test that each pair has its own value.
58 assert( get_a() === 12 );
59
60 });
61 // end closures
62
63
64 // start return_this
65 TEST('return_this', function()
66 {
67 var return_this = function(){
68 return this;
69 };
70
71 var default_this = return_this();
72 assert( default_this.telltail === 'global' );
73
74 var obj = {};
75 obj.return_this = return_this;
76 assert( obj.return_this === return_this );
77
78 assert( obj.return_this() === obj );
79 assert( obj['return_this']() === obj );
80
81 assert( return_this.call(obj) === obj );
82 assert( return_this.apply(obj) === obj );
83
84 assert( return_this.call(undefined).telltail === 'global' );
85 assert( return_this.apply(undefined).telltail === 'global' );
86
87 });
88 // end return_this
89
90
91 // start transient-bind
92 TEST('transient-bind', function()
93 {
94 // Set up the test object.
95 var return_this = function(){
96 return this;
97 };
98 var obj = {
99 return_this : return_this
100 };
101
102 // Deferring method call changes the outcome.
103 var method_deferred = obj.return_this;
104 assert( method_deferred === obj.return_this );
105 assert( method_deferred() !== obj.return_this() );
106
107 // The two outcomes, precisely stated.
108 assert( obj.return_this() === obj );
109 assert( method_deferred().telltail === 'global' );
110
111 });
112 // end transient-bind
113
114
115 // start millers-device
116 TEST('millers-device', function()
117 {
118 var array = [];
119 var obj = {};
120 var fn = function(){};
121
122 assert( typeof array === 'object' );
123 assert( '' + obj === '[object Object]' );
124
125 assert( obj.toString() === '[object Object]' );
126
127 var object_toString = obj.toString;
128
129 assert( object_toString.call(array) === '[object Array]' );
130 assert( object_toString.call(fn) === '[object Function]' );
131
132 });
133 // end millers-device
134
135
136 // start return_arguments
137 TEST('return_arguments', function()
138 {
139 var return_arguments = function(){
140 return arguments;
141 };
142
143 var my_arguments = return_arguments(0, 1);
144
145 assert( my_arguments.length === 2 );
146
147 assert( my_arguments[0] === 0 );
148 assert( my_arguments[1] === 1 );
149
150 assert( '' + my_arguments === '[object Object]' );
151 assert( '' + [0, 1] === '0,1' );
152
153 var array_slice = [].slice;
154 var my_arguments_fixed = array_slice.call( my_arguments );
155
156 assert( '' + my_arguments_fixed === '0,1');
157
158 var obj = {};
159 assert( obj.toString.call( my_arguments_fixed ) === '[object Array]' );
160
161 });
162 // end return_arguments
163
164
165 // start new-operator
166 TEST('new-operator', function()
167 {
168 var this_in_Fn;
169
170 var Fn = function(){
171 this_in_Fn = this;
172 };
173
174 this_in_Fn = null;
175 var non_instance = Fn();
176 assert( non_instance === undefined );
177 assert( this_in_Fn.telltail === 'global');
178
179 this_in_Fn = null;
180 var instance = new Fn();
181 assert( instance === this_in_Fn );
182 assert( instance.telltail === undefined );
183
184 Fn.prototype.telltail = 'instance-of-Fn';
185 assert( instance.telltail === 'instance-of-Fn' );
186
187 Fn.prototype = {
188 telltail : 'prototype-is-changed'
189 };
190 var second_instance = new Fn();
191 assert( second_instance.telltail === 'prototype-is-changed' );
192
193 Fn.prototype = second_instance;
194 second_instance.i = 42;
195
196 var third_instance = new Fn();
197 assert( third_instance.telltail === 'prototype-is-changed' );
198 assert( third_instance.i === 42 );
199
200 });
201 // end new-operator