Firefox spell check requires dictionary

Maria H.'s version of Firefox didn't highlight misspelt words in multi-line fields, although the Check my spelling as I type option is checked. I found that I had a English / United States dictionary installed (probably from a previous installation) while she didn't, so the spell check worked on my PC but not on hers. It seems that the Firefox spell checker only works after you install a dictionary; another one of those things that are obvious in hindsight.

Microsoft Visio 2003 insert page annoyance

When you insert a new page in MS Visio 2003, the page added in the right-most position, after all other page tabs. This behaviour is different from MS Excel, where a sheet is added before the current sheet. Visio's behaviour is annoying because after I create a new page, I have to move it to the position I want.

Microsoft Word 2003 symbol dialog

By accident, I found that if you double-click on a symbol character in your document in Microsoft Word 2003, the Symbol dialog is displayed. However, how does MS Word define a symbol? For instance, the dialog doesn't appear if you click on a copyright symbol but it appears if you click on a smiley face symbol.

References

• 6 tips for adding international characters and symbols to your document

Dispatch, Static versus Dynamic, Single versus Double or Multiple

I read Stuart Holloway's Java.Next #3 Dispatch and decided to make clear to myself the concept of Dispatch and how it is used.

Dispatch means to call a method of an object and is normally applicable in the context of object-oriented programming. The rest of this summary assumes that there is more than one function with the same name and revolves around selecting the function (or method) to call (see Multiple Dispatch).

Static Dispatch that the system can pick the function to call at compile-time, as opposed to Dynamic Dispatch where the system has to choose the function to call at run-time. Dynamic dispatch can be supported by the programming language (e.g. polymorphism) or implemented in a program (e.g. case-statement).

Single Dispatch means that the system picks the function to call based on one parameter. In common object-oriented languages (e.g. C++, Java or C#), that parameter is the type of the object (see Dynamic Dispatch). For example:

class A { fn(); }
class B { fn(); }

A a;
B b;

a.fn();

When the system encounters a.fn(), the system calls the function fn() in class A because the object a is of the type A.

Multiple Dispatch (or Multimethods) means that more than one parameter is considered when calling a function. Multiple Dispatch gives mentions some languages the support this feature but I'm only familiar with Groovy, so I found this example by Danno Ferrin where the function chosen depends on the types of the object and function argument.

Double Dispatch is a special case of multiple dispatch (see Double Dispatch) where two parameters are considered and it is often implemented using the Visitor Pattern in single dispatch languages.

References

• Java.Next #3 Dispatch
• Dynamic Dispatch
• Multiple Dispatch
• Groovy and (Dynamic Dispatch|Multiple Dispatch|MultiMethods): A Simpler Example
• Double Dispatch
• Visitor Pattern