@@ -40,9 +40,9 @@
<key>caret</key>
<dict>
<key>column</key>
- <integer>25</integer>
+ <integer>22</integer>
<key>line</key>
- <integer>3</integer>
+ <integer>246</integer>
</dict>
<key>firstVisibleColumn</key>
<integer>0</integer>
engglog.tmproj
@@ -324,10 +324,115 @@ $(document).ready(myFeature.init);
></li
></ul
></div
+ ><div id="advanced-javascript"
+ ><h2
+ >Advanced Javascript</h2
+ ><div id="references-2"
+ ><h3
+ >References</h3
+ ><ul
+ ><li
+ ><a href="http://ejohn.org/apps/learn/#24"
+ >Advanced Javascript by John Resig</a
+ ></li
+ ><li
+ ><a href="http://news.ycombinator.com/item?id=846365"
+ >Hacker News discussion on <code
+ >this</code
+ > keyword</a
+ ></li
+ ><li
+ ><a href="http://justin.harmonize.fm/index.php/2009/09/an-introduction-to-javascripts-this/"
+ >Another post on <code
+ >this</code
+ > keyword</a
+ ></li
+ ></ul
+ ></div
+ ><div id="function-context"
+ ><h3
+ >Function Context</h3
+ ><p
+ ><code
+ >this</code
+ > in a a function refers to the context. If a function is defined globally like below, <code
+ >this</code
+ > refers to the global context</p
+ ><pre
+ ><code
+ >function katana(){
+ this.isSharp = true;
+}
+katana();
+assert( isSharp === true, "A global object now exists with that name and value." );
+</code
+ ></pre
+ ><p
+ >However, if it is defined as an object variable like below, it refers to the object</p
+ ><pre
+ ><code
+ >var katana = {
+ isSharp: true,
+ use: function(){
+ this.isSharp = !this.isSharp;
+ }
+};
+katana.use()
+assert( !katana.isSharp, "Verify the value of isSharp has been changed." );
+</code
+ ></pre
+ ><p
+ >The context can be changed by using <code
+ >call</code
+ > on the function</p
+ ><pre
+ ><code
+ >var object = {};
+function fn(){
+ return this;
+}
+assert( fn() == this, "The context is the global object." );
+assert( fn.call(object) == object, "The context is changed to a specific object." );
+
+// Example 2 (using apply)
+function add(a, b){
+ return a + b;
+}
+assert( add.call(this, 1, 2) == 3, ".call() takes individual arguments" );
+assert( add.apply(this, [1, 2]) == 3, ".apply() takes an array of arguments" );
+</code
+ ></pre
+ ></div
+ ><div id="using-new"
+ ><h3
+ >Using <code
+ >new</code
+ ></h3
+ ><p
+ >In the code below, a simple call to <code
+ >Ninja</code
+ > returns the value of the evaluated function, whereas using <code
+ >new Ninja</code
+ > returns the function object.</p
+ ><pre
+ ><code
+ >function Ninja(){
+ this.name = "Ninja";
+}
+
+var ninjaA = Ninja();
+assert( !ninjaA, "Is undefined, not an instance of Ninja." );
+
+var ninjaB = new Ninja();
+assert( ninjaB.name == "Ninja", "Property exists on the ninja instance." );
+</code
+ ></pre
+ ></div
+ ></div
><div id="bloom-filters-in-haskell"
><h2
>Bloom Filters in Haskell</h2
- ><div id="references-2"
+ ><div id="references-3"
><h3
>References</h3
><ol style="list-style-type: decimal;"
log.html
@@ -244,6 +244,77 @@ $(document).ready(myFeature.init);
* [Algorithm Design Manual](http://www.amazon.com/dp/0387948600)
+## Advanced Javascript
+
+### References
+
+* [Advanced Javascript by John Resig](http://ejohn.org/apps/learn/#24)
+* [Hacker News discussion on `this` keyword](http://news.ycombinator.com/item?id=846365)
+* [Another post on `this` keyword](http://justin.harmonize.fm/index.php/2009/09/an-introduction-to-javascripts-this/)
+
+### Function Context
+
+`this` in a a function refers to the context. If a function is defined
+globally like below, `this` refers to the global context
+
+~~~~~~
+function katana(){
+ this.isSharp = true;
+}
+katana();
+assert( isSharp === true, "A global object now exists with that name and value." );
+~~~~~~
+
+However, if it is defined as an object variable like below, it refers to the
+object
+
+~~~~~~
+var katana = {
+ isSharp: true,
+ use: function(){
+ this.isSharp = !this.isSharp;
+ }
+};
+katana.use()
+assert( !katana.isSharp, "Verify the value of isSharp has been changed." );
+~~~~~~
+
+The context can be changed by using `call` on the function
+
+~~~~~~
+var object = {};
+function fn(){
+ return this;
+}
+assert( fn() == this, "The context is the global object." );
+assert( fn.call(object) == object, "The context is changed to a specific object." );
+
+// Example 2 (using apply)
+function add(a, b){
+ return a + b;
+}
+assert( add.call(this, 1, 2) == 3, ".call() takes individual arguments" );
+assert( add.apply(this, [1, 2]) == 3, ".apply() takes an array of arguments" );
+~~~~~~
+
+### Using `new`
+
+In the code below, a simple call to `Ninja` returns the value of the evaluated
+function, whereas using `new Ninja` returns the function object.
+
+~~~~~~
+function Ninja(){
+ this.name = "Ninja";
+}
+
+var ninjaA = Ninja();
+assert( !ninjaA, "Is undefined, not an instance of Ninja." );
+
+var ninjaB = new Ninja();
+assert( ninjaB.name == "Ninja", "Property exists on the ninja instance." );
+~~~~~~
+
+
## Bloom Filters in Haskell
### References
log.txt
ce8a818d5d10e2d15507dba891e01bcfe7437bab
Deepak Jois
deepak.jois@gmail.com
http://github.com/deepakjois/engglog/commit/d2fcce77bef20320cf6c813ff7429a83d8d13a9c
d2fcce77bef20320cf6c813ff7429a83d8d13a9c
2009-09-28T10:22:07-07:00
2009-09-28T10:22:07-07:00
Adding JS stuff
b4cb0a7146419feb8cd6b771c3e4f9d39ef3f540
Deepak Jois
deepak.jois@gmail.com